WHY WOULD A PREGNANCY TEST BE NEGATIVE IN A CRYPTIC PREGNANCY?

UNDERSTANDING FALSE-NEGATIVE PREGNANCY TESTS, hCG HORMONE, CRYPTIC PREGNANCY, URINE TEST LIMITATIONS, BLOOD β-hCG, ULTRASOUND CONFIRMATION, MANAGEMENT, HOME CARE, AND WHEN TO SEEK URGENT MEDICAL HELP

INTRODUCTION: HOW CAN A WOMAN BE PREGNANT IF THE PREGNANCY TEST IS NEGATIVE?

One of the most confusing situations in reproductive medicine occurs when a woman experiences pregnancy symptoms but repeatedly obtains a negative pregnancy test.

Questions immediately arise:

• Can a pregnancy test be wrong?
• Can I really be pregnant despite a negative test?
• Does a negative pregnancy test completely rule out pregnancy?
• Why do some women discover pregnancy months later after earlier negative tests?
• What exactly is a cryptic pregnancy?

These questions have generated enormous public interest, but they have also led to widespread myths and misinformation.

The scientific reality is reassuring:

Most pregnancy tests are highly accurate when used correctly at the appropriate time.

However, no medical test is perfect.

Although uncommon, false-negative pregnancy tests can occur under specific clinical circumstances.

Understanding why requires an appreciation of how pregnancy develops and how pregnancy tests work.

WHAT IS A CRYPTIC PREGNANCY?

A cryptic pregnancy is a real pregnancy that remains unrecognized until much later than expected.

Unlike false pregnancy (pseudocyesis), a cryptic pregnancy involves:

• Fertilization.
• Implantation.
• Placental development.
• Fetal growth.
• Production of pregnancy hormones.

The pregnancy is genuine.

The baby is real.

The challenge lies in recognizing the pregnancy early.

WHAT IS A FALSE-NEGATIVE PREGNANCY TEST?

A false-negative pregnancy test occurs when:

• A woman is actually pregnant.

but

• The pregnancy test reports a negative result.

This differs from a false-positive test, where the test indicates pregnancy despite the absence of one.

False-negative results are uncommon but medically recognized.

HOW DO PREGNANCY TESTS WORK?

Pregnancy tests do not detect the baby.

They detect a hormone.

That hormone is:

Human Chorionic Gonadotropin (hCG)

Shortly after implantation, specialized placental cells begin producing hCG.

As pregnancy progresses:

• Blood hCG rises.
• Urine hCG rises.
• Pregnancy tests become positive.

Without sufficient hCG, pregnancy tests remain negative.

WHAT IS hCG?

Human Chorionic Gonadotropin is one of the earliest hormones produced during pregnancy.

Its important functions include:

• Supporting the corpus luteum.
• Maintaining progesterone production.
• Preserving the uterine lining.
• Supporting early pregnancy until the placenta matures.

Because pregnancy tests detect hCG rather than the fetus itself, anything affecting hCG detection may influence test results.

HOW SOON DOES hCG APPEAR?

After fertilization:

• The embryo travels toward the uterus.
• Implantation usually occurs several days later.
• hCG production begins after implantation.
• hCG gradually increases over time.

Very early in pregnancy, hCG levels may still be too low for some urine tests to detect.

This is one reason early testing may produce false-negative results.

URINE PREGNANCY TESTS VERSUS BLOOD β-hCG TESTS

There are two principal methods of pregnancy testing.

URINE PREGNANCY TEST

Urine tests:

• Detect hCG in urine.
• Are convenient.
• Are inexpensive.
• Can be performed at home.

However, their accuracy depends on:

• Timing.
• Urine concentration.
• Correct technique.
• Test sensitivity.

QUANTITATIVE SERUM β-hCG

Blood testing:

• Measures the exact concentration of hCG.
• Detects much lower hormone levels.
• Is more sensitive.
• Detects pregnancy earlier than most urine tests.

When pregnancy is strongly suspected despite a negative urine test, doctors frequently request quantitative serum β-hCG.

WHY CAN A PREGNANCY TEST BE NEGATIVE IN A CRYPTIC PREGNANCY?

Several medically recognized situations may produce an initial false-negative result.

These include:

• Testing too early.
• Delayed implantation.
• Diluted urine.
• Incorrect testing technique.
• Low-sensitivity pregnancy kits.
• Rare laboratory limitations.
• Very rare high-dose hook effect.
• Incorrect interpretation of results.

Each deserves careful explanation.

TESTING TOO EARLY

This is the most common reason for a false-negative pregnancy test.

If testing occurs before enough hCG has accumulated:

• Urine hCG remains below the detection threshold.
• The test appears negative.

This does not necessarily mean pregnancy is absent.

Repeating the test after several days often clarifies the diagnosis.

DELAYED OVULATION

Many women assume ovulation occurs exactly halfway through every menstrual cycle.

In reality:

Ovulation may occur:

• Earlier.
• Later.
• Irregularly.

If ovulation occurs later than expected:

• Fertilization occurs later.
• Implantation occurs later.
• hCG production begins later.

Consequently, testing based on the expected menstrual date may be premature.

DELAYED IMPLANTATION

The embryo normally implants several days after fertilization.

Occasionally implantation occurs later than expected.

Since hCG production begins only after implantation:

Delayed implantation delays:

• Rising hCG.
• Positive pregnancy tests.

DILUTED URINE

Urine concentration greatly influences home pregnancy tests.

Women who drink large amounts of fluid before testing may produce diluted urine.

Diluted urine contains:

• Lower hCG concentration.

This may occasionally reduce the ability of some tests to detect pregnancy.

For this reason, many healthcare professionals recommend using the first urine passed in the morning, as it is usually the most concentrated.

INCORRECT TESTING TECHNIQUE

Home pregnancy tests require careful use.

Errors include:

• Not following instructions.
• Insufficient urine.
• Excess urine.
• Incorrect timing.
• Reading results too early.
• Reading results long after the recommended time.

Improper technique may affect interpretation.

EXPIRED OR DAMAGED TEST KITS

Pregnancy tests have expiration dates.

Exposure to:

• Heat.
• Moisture.
• Improper storage.

may reduce reliability.

Always check:

• Expiration date.
• Package integrity.
• Manufacturer instructions.

LOW-SENSITIVITY PREGNANCY TESTS

Different pregnancy tests detect different minimum concentrations of hCG.

Some tests identify pregnancy earlier than others.

Very early pregnancies may not yet reach the detection threshold of less sensitive tests.

THE RARE HIGH-DOSE HOOK EFFECT

In very uncommon situations, extremely high levels of hCG can interfere with certain immunoassays and produce an unexpectedly negative or weakly positive result. This phenomenon is known as the high-dose hook effect.

It has been reported in rare circumstances, such as some advanced pregnancies or certain abnormal pregnancies.

Healthcare professionals may suspect this when clinical findings strongly suggest pregnancy despite an unexpected test result. Additional laboratory methods, repeat testing, or dilution of the sample may help clarify the diagnosis.

LABORATORY FACTORS

Although uncommon, technical or laboratory issues may occasionally contribute to inaccurate results.

Examples include:

• Specimen handling errors.
• Analytical limitations.
• Equipment malfunction.

Clinical findings always take priority over a single laboratory result.

WHY SYMPTOMS ALONE CANNOT CONFIRM PREGNANCY

Symptoms such as:

• Nausea.
• Fatigue.
• Breast tenderness.
• Missed periods.
• Food cravings.
• Frequent urination.

may occur in:

• Normal pregnancy.
• Hormonal disorders.
• Thyroid disease.
• PCOS.
• Perimenopause.
• Certain medications.
• Gastrointestinal disorders.

Doctors therefore combine symptoms with laboratory investigations and ultrasound.

WHEN SHOULD A NEGATIVE TEST BE REPEATED?

Doctors commonly recommend repeating a urine pregnancy test when:

• Testing was performed very early.
• Menstruation has still not occurred.
• Pregnancy symptoms persist.
• The first test may have been affected by diluted urine or user error.

If symptoms continue despite repeated negative tests, medical evaluation—including quantitative serum β-hCG and, when appropriate, ultrasound—is recommended.

CONCLUSION 

A negative pregnancy test does not always exclude pregnancy, particularly when testing is performed very early or under circumstances that reduce the accuracy of urine hCG detection. Cryptic pregnancy is a genuine pregnancy that may remain unrecognized because of subtle symptoms, delayed testing, irregular menstrual cycles, or, less commonly, false-negative test results. Understanding how pregnancy tests detect hCG—and recognizing the limitations of home testing—helps explain why some pregnancies are diagnosed later than expected. When pregnancy is still suspected despite a negative urine test, repeat testing, quantitative serum β-hCG measurement, and ultrasound provide a more reliable pathway to diagnosis.

THE MOST COMMON REASONS FOR A FALSE-NEGATIVE PREGNANCY TEST

When a woman later discovers she is pregnant after receiving one or more negative pregnancy tests, she often wonders how this could have happened.

Although modern pregnancy tests are highly accurate when used correctly, certain biological, technical, and timing-related factors can occasionally produce a false-negative result.

Understanding these factors helps healthcare professionals diagnose pregnancy accurately while preventing unnecessary anxiety and delayed antenatal care.

TESTING TOO EARLY: THE MOST COMMON CAUSE OF A FALSE-NEGATIVE RESULT

The single most common reason for a false-negative pregnancy test is performing the test before enough human chorionic gonadotropin (hCG) has accumulated in the body.

Pregnancy begins with:

• Fertilization.
• Embryo development.
• Implantation into the uterine lining.

Only after implantation does the developing placenta begin producing hCG.

If a woman tests before sufficient hCG has entered the urine, the pregnancy test may remain negative despite an existing early pregnancy.

WHY EARLY TESTING CAN BE MISLEADING

Many women test immediately after:

• Missing a period.
• Experiencing breast tenderness.
• Feeling nauseated.
• Suspecting pregnancy.

However, menstrual cycles vary considerably.

If ovulation or implantation occurred later than expected, hCG production may not yet have reached detectable levels.

For this reason, healthcare professionals often recommend repeating the test after 48–72 hours if menstruation has not begun and pregnancy remains possible.

LATE OVULATION

Most textbooks describe ovulation occurring approximately midway through the menstrual cycle.

In reality, ovulation varies significantly.

It may occur:

• Earlier.
• Later.
• Irregularly.

Late ovulation shifts the entire reproductive timeline.

Consequently:

• Fertilization occurs later.
• Implantation occurs later.
• hCG production begins later.
• Pregnancy testing becomes positive later.

Women with irregular cycles are particularly affected.

DELAYED IMPLANTATION

Even after fertilization, implantation does not occur immediately.

Normally, implantation occurs several days after conception.

Occasionally implantation is delayed.

Because hCG production begins only after successful implantation:

Delayed implantation postpones:

• Detectable hCG.
• Positive urine tests.
• Positive blood tests during the earliest phase.

This explains why some women initially receive negative results before later testing positive.

IRREGULAR MENSTRUAL CYCLES

Women with irregular menstrual cycles often find pregnancy dating difficult.

Irregular cycles may result from:

• Polycystic Ovary Syndrome (PCOS).
• Thyroid disorders.
• Chronic stress.
• Significant weight changes.
• Intensive exercise.
• Perimenopause.
• Hypothalamic dysfunction.

Because ovulation becomes unpredictable, testing based on calendar dates may occur too early.

POLYCYSTIC OVARY SYNDROME (PCOS)

PCOS is one of the most common endocrine disorders affecting women of reproductive age.

Typical features include:

• Irregular menstruation.
• Delayed ovulation.
• Infertility.
• Acne.
• Weight gain.
• Excess facial hair.

Women with PCOS frequently struggle to identify the exact timing of ovulation.

Consequently, pregnancy tests performed according to expected menstrual dates may produce false-negative results simply because conception occurred later than assumed.

BREASTFEEDING AFTER CHILDBIRTH

Breastfeeding suppresses ovulation in many women.

However:

Ovulation may resume unexpectedly before menstruation returns.

A breastfeeding woman may therefore:

• Conceive.
• Remain unaware of ovulation.
• Misjudge pregnancy timing.
• Test too early.

This occasionally contributes to delayed pregnancy recognition.

PERIMENOPAUSE

Women approaching menopause often experience:

• Irregular periods.
• Missed cycles.
• Hormonal fluctuations.
• Hot flushes.
• Sleep disturbance.

Because menstrual irregularity becomes common, pregnancy may not initially be suspected.

If conception occurs unexpectedly, pregnancy testing may be delayed or incorrectly timed.

DILUTED URINE

The concentration of urine directly affects home pregnancy testing.

Large fluid intake before testing may dilute urinary hCG.

Examples include:

• Drinking several glasses of water.
• Excessive tea or coffee intake.
• Sports hydration.
• Intravenous fluids before testing.

Lower urinary hCG concentration may occasionally reduce the sensitivity of home pregnancy tests.

WHY FIRST-MORNING URINE IS RECOMMENDED

The first urine passed after waking is usually the most concentrated.

It contains:

• Higher hCG concentration.
• Less dilution.
• Greater likelihood of detecting early pregnancy.

For women testing very early, first-morning urine generally provides the best chance of obtaining an accurate result.

USER ERRORS

Incorrect use of home pregnancy tests remains an important cause of misleading results.

Common mistakes include:

• Using insufficient urine.
• Applying excessive urine.
• Reading instructions incorrectly.
• Reading results before the recommended time.
• Reading results long after the recommended time.
• Failing to repeat testing when appropriate.

Carefully following the manufacturer's instructions improves accuracy.

EXPIRED OR IMPROPERLY STORED TEST KITS

Pregnancy tests are medical diagnostic devices.

Their performance depends upon proper storage.

Problems include:

• Expired tests.
• Heat exposure.
• Moisture exposure.
• Damaged packaging.
• Manufacturing defects.

Women should always check:

• Expiration date.
• Package integrity.
• Storage recommendations.

LOW-SENSITIVITY PREGNANCY TESTS

Not all pregnancy tests detect the same minimum concentration of hCG.

Some tests identify pregnancy earlier than others.

Lower-sensitivity tests may require:

• Higher urinary hCG concentrations.
• More advanced pregnancy.

Consequently, early pregnancy may initially remain undetected.

THE HIGH-DOSE HOOK EFFECT

One of the rarest explanations for an unexpected negative pregnancy test is the high-dose hook effect.

In unusual situations involving extremely high concentrations of hCG, certain laboratory immunoassays or some urine pregnancy tests may produce a falsely negative or unexpectedly weak result because the very high hormone level interferes with the test reaction.

Although this phenomenon has been described in medical literature, it is very uncommon and should not be considered a routine explanation for negative pregnancy tests.

When clinical suspicion remains high despite an unexpected negative result, healthcare professionals may repeat testing, perform quantitative serum β-hCG measurements, or use additional laboratory techniques to clarify the diagnosis.

LABORATORY LIMITATIONS

Although modern laboratories maintain strict quality standards, no diagnostic test is completely free from technical limitations.

Rare issues include:

• Specimen labeling errors.
• Sample contamination.
• Analytical interference.
• Equipment malfunction.

Unexpected results should always be interpreted together with the woman's symptoms and examination findings.

WHY QUANTITATIVE SERUM β-hCG IS MORE RELIABLE

Blood β-hCG testing offers several important advantages.

It:

• Detects pregnancy earlier.
• Measures the exact hormone concentration.
• Allows serial monitoring.
• Helps diagnose ectopic pregnancy.
• Assists in Pregnancy of Unknown Location.
• Helps assess pregnancy progression.

When urine testing and clinical findings do not agree, quantitative serum β-hCG becomes an invaluable investigation.

WHY REPEAT TESTING IS SOMETIMES NECESSARY

Doctors frequently recommend repeat testing because pregnancy is a dynamic biological process.

A single negative result does not always provide the complete picture.

Repeating the test after an appropriate interval allows:

• Rising hCG to become detectable.
• Confirmation or exclusion of pregnancy.
• More accurate clinical decision-making.

Persistence of pregnancy symptoms despite repeated negative urine tests warrants further medical evaluation.

CLINICAL SCENARIO 1

A woman with irregular menstrual cycles performs a home pregnancy test one day after expecting her period.

The result is negative.

One week later she repeats the test.

It is positive.

The most likely explanation is that ovulation and implantation occurred later than expected, making the first test too early rather than indicating an error in the pregnancy itself.

CLINICAL SCENARIO 2

A breastfeeding mother with no menstrual periods develops fatigue and nausea.

She performs a home pregnancy test after drinking a large amount of water.

The result is negative.

Because symptoms persist, her doctor orders a quantitative serum β-hCG test and an ultrasound, which confirm an early intrauterine pregnancy.

This illustrates why persistent pregnancy symptoms should be evaluated even when an initial home test is negative.

CLINICAL SIGNIFICANCE

False-negative pregnancy tests are uncommon but clinically important because they can delay recognition of pregnancy and postpone appropriate antenatal care. The most frequent causes are testing too early, late ovulation, delayed implantation, diluted urine, irregular menstrual cycles, and user-related errors. Less commonly, low-sensitivity test kits, laboratory limitations, or the rare high-dose hook effect may contribute. When pregnancy is still suspected despite a negative urine test, repeat testing, quantitative serum β-hCG measurement, and ultrasound provide a more accurate and reliable diagnostic approach.

CONCLUSION 

Most false-negative pregnancy tests occur because the test is performed before urinary hCG has reached detectable levels or because factors such as irregular ovulation, delayed implantation, diluted urine, incorrect test technique, or less sensitive test kits reduce the likelihood of detection. Rare laboratory limitations and the high-dose hook effect may also contribute in exceptional circumstances. Recognizing these possibilities helps clinicians avoid premature exclusion of pregnancy and ensures that women with persistent pregnancy symptoms receive appropriate follow-up through repeat testing, quantitative serum β-hCG measurement, and ultrasound evaluation.

WHY DO SOME WOMEN NOT REALIZE THEY ARE PREGNANT?

One of the defining features of cryptic pregnancy is that the pregnancy goes unrecognized for weeks or even months despite the presence of a developing baby.

This delayed recognition rarely results from a single cause.

Instead, it usually reflects a combination of subtle symptoms, irregular menstrual patterns, physiological differences, and, in some cases, psychological factors.

Understanding these situations helps explain why pregnancy may remain hidden despite modern diagnostic tests.

VERY MILD PREGNANCY SYMPTOMS

Many women expect pregnancy to produce unmistakable symptoms such as:

• Severe morning sickness.
• Marked breast enlargement.
• Extreme fatigue.
• Rapid abdominal enlargement.
• Frequent vomiting.

However, pregnancy symptoms vary greatly from one woman to another.

Some women experience only:

• Mild nausea.
• Occasional tiredness.
• Slight breast tenderness.
• Minimal weight gain.
• Very subtle abdominal enlargement.

Because these symptoms are easily attributed to stress, work, diet, or hormonal changes, pregnancy may not be suspected.

BLEEDING MISTAKEN FOR MENSTRUAL PERIODS

One of the most important reasons cryptic pregnancy goes unrecognized is vaginal bleeding that resembles a menstrual period.

Bleeding may occur because of:

• Implantation bleeding early in pregnancy.
• Cervical ectropion.
• Cervical irritation.
• Subchorionic hematoma.
• Other pregnancy-related causes requiring medical assessment.

Some women mistake these bleeding episodes for normal menstruation.

As a result, they believe pregnancy is impossible and do not seek testing or antenatal care.

It is important to remember that bleeding during pregnancy is not a true menstrual period, even if it occurs around the expected time of menstruation.

OBESITY OR LARGER BODY HABITUS

Body shape can influence how obvious a pregnancy appears.

Women with overweight or obesity may notice:

• Less obvious abdominal enlargement.
• Slower recognition of uterine growth.
• Difficulty distinguishing pregnancy-related weight gain from existing body weight.

Although pregnancy can be less apparent externally, the fetus continues to develop normally.

Ultrasound remains the most reliable method of confirming pregnancy.

ANTERIOR PLACENTA

An anterior placenta develops on the front wall of the uterus.

Because the placenta lies between the fetus and the abdominal wall:

• Early fetal movements may be less noticeable.
• Kicks may feel softer.
• Quickening may be recognized later than usual.

Delayed perception of fetal movement can contribute to later recognition of pregnancy, although it does not affect fetal development.

MISINTERPRETING FETAL MOVEMENTS

Early fetal movements are often subtle.

Women may mistake them for:

• Gas.
• Intestinal activity.
• Muscle twitching.
• Digestive movements.

As pregnancy advances, movements usually become stronger, but delayed recognition may already have occurred.

PREGNANCY DENIAL

Pregnancy denial is a recognized psychological condition in which a woman does not recognize or accept that she is pregnant despite objective evidence.

It is important to distinguish pregnancy denial from intentional concealment.

In pregnancy denial:

• The pregnancy is real.
• The fetus is present.
• The woman genuinely does not recognize or psychologically accept the pregnancy.

Not every cryptic pregnancy involves pregnancy denial, and not every woman with pregnancy denial has the same psychological background.

Compassionate assessment is essential.

BREASTFEEDING AND DELAYED RECOGNITION

Women who are breastfeeding may:

• Have irregular or absent menstrual periods.
• Experience breast fullness related to lactation.
• Feel fatigued because of infant care.

These normal postpartum changes may overlap with early pregnancy symptoms, making recognition more difficult.

Because ovulation can resume before menstruation returns, pregnancy is possible even in the absence of regular periods.

PERIMENOPAUSE

Women approaching menopause often experience:

• Irregular menstrual cycles.
• Missed periods.
• Mood changes.
• Sleep disturbance.
• Weight fluctuations.

These symptoms may resemble pregnancy or mask it.

Consequently, pregnancy may not initially be considered, particularly in women who believe they are no longer fertile.

POLYCYSTIC OVARY SYNDROME (PCOS)

Women with PCOS frequently experience:

• Irregular ovulation.
• Infrequent menstruation.
• Unpredictable cycles.

Because missed periods are already common, pregnancy may not be suspected until much later.

Healthcare professionals therefore recommend pregnancy testing whenever pregnancy is possible, regardless of menstrual irregularity.

ECTOPIC PREGNANCY

Occasionally, pregnancy tests may initially be difficult to interpret in women with ectopic pregnancy, particularly very early in its course.

Ectopic pregnancy occurs when implantation takes place outside the uterus, most commonly within a fallopian tube.

Symptoms may include:

• Vaginal bleeding.
• One-sided pelvic pain.
• Shoulder-tip pain.
• Dizziness.
• Fainting.

Ectopic pregnancy is a medical emergency requiring immediate evaluation.

PREGNANCY OF UNKNOWN LOCATION (PUL)

Sometimes:

• Pregnancy tests are positive or borderline.
• Ultrasound cannot yet identify a pregnancy inside or outside the uterus.

This situation is called:

Pregnancy of Unknown Location

Possible explanations include:

• Very early intrauterine pregnancy.
• Ectopic pregnancy.
• Early pregnancy loss.

Doctors usually recommend:

• Serial quantitative β-hCG measurements.
• Repeat ultrasound.
• Close follow-up.

WHY ULTRASOUND BECOMES ESSENTIAL

When pregnancy symptoms continue despite uncertain test results, ultrasound becomes one of the most important diagnostic tools.

Ultrasound can demonstrate:

• Gestational sac.
• Yolk sac.
• Embryo.
• Fetal heartbeat.
• Placenta.
• Amniotic fluid.
• Gestational age.

Unlike urine testing, ultrasound directly visualizes the pregnancy.

WHY QUANTITATIVE SERUM β-hCG IS PREFERRED IN UNCERTAIN CASES

Blood β-hCG testing offers several advantages over home urine testing.

It can:

• Detect lower hormone concentrations.
• Confirm early pregnancy.
• Monitor changes over time.
• Assist in diagnosing ectopic pregnancy.
• Help evaluate Pregnancy of Unknown Location.

Serial measurements are often more informative than a single value.

COMMON CLINICAL PITFALLS

Doctors avoid relying on only one piece of information.

Potential pitfalls include:

• Assuming bleeding equals menstruation.
• Assuming one negative urine test excludes pregnancy.
• Ignoring persistent pregnancy symptoms.
• Overlooking irregular ovulation.
• Failing to repeat testing when indicated.
• Delaying ultrasound evaluation.

Comprehensive assessment minimizes diagnostic errors.

DIFFERENTIAL DIAGNOSS

When pregnancy symptoms persist despite a negative urine test, healthcare professionals consider several possible explanations, including:

• Very early intrauterine pregnancy.
• Cryptic pregnancy.
• Ectopic pregnancy.
• Pregnancy of Unknown Location.
• Early pregnancy loss.
• False pregnancy (pseudocyesis).
• Polycystic Ovary Syndrome.
• Thyroid disorders.
• Hyperprolactinemia.
• Perimenopause.
• Ovarian cysts.
• Medication-related hormonal changes.

Careful evaluation helps distinguish among these conditions.

WHEN SHOULD A WOMAN SEEK URGENT MEDICAL ATTENTION?

Immediate medical evaluation is necessary if a negative pregnancy test is accompanied by:

• Severe lower abdominal pain.
• One-sided pelvic pain.
• Heavy vaginal bleeding.
• Shoulder-tip pain.
• Fainting.
• Persistent dizziness.
• Fever.
• Severe vomiting.
• Continued absence of menstruation with worsening pregnancy symptoms.

These symptoms may indicate serious conditions such as ectopic pregnancy or significant pregnancy complications.

WHY DOCTORS NEVER RELY ON A SINGLE TEST

Modern obstetric care emphasizes that diagnosis is based on the whole clinical picture.

Doctors combine:

• Medical history.
• Menstrual history.
• Physical examination.
• Urine pregnancy testing.
• Quantitative serum β-hCG.
• Repeat β-hCG measurements when appropriate.
• Ultrasound findings.

This comprehensive approach provides the highest diagnostic accuracy.

CLINICAL SIGNIFICANCE

Cryptic pregnancy demonstrates that pregnancy recognition depends on more than a single home pregnancy test. Mild symptoms, irregular menstrual cycles, bleeding mistaken for menstruation, obesity, breastfeeding, perimenopause, PCOS, and other clinical factors may delay diagnosis. Although false-negative urine pregnancy tests are uncommon, they can occur under specific circumstances. Persistent pregnancy symptoms should therefore prompt further evaluation with quantitative serum β-hCG testing and ultrasound rather than reassurance based solely on a single negative urine result.

CONCLUSION 

Delayed recognition of cryptic pregnancy is usually multifactorial, involving subtle symptoms, irregular ovulation, bleeding mistaken for menstrual periods, physiological variations such as an anterior placenta, and, in some cases, psychological factors such as pregnancy denial. Conditions including PCOS, breastfeeding, perimenopause, ectopic pregnancy, and Pregnancy of Unknown Location may further complicate diagnosis. Because home urine tests have limitations, clinicians rely on quantitative serum β-hCG measurements, repeat testing when indicated, and ultrasound imaging to establish or exclude pregnancy with confidence. A careful, evidence-based diagnostic approach ensures timely antenatal care and protects both maternal and fetal health.

HOW DO DOCTORS EVALUATE A WOMAN WHO HAS PREGNANCY SYMPTOMS BUT A NEGATIVE PREGNANCY TEST?

When a woman continues to experience symptoms strongly suggestive of pregnancy despite one or more negative pregnancy tests, healthcare professionals do not rely on the test result alone.

Instead, they perform a comprehensive clinical assessment to determine whether:

• The pregnancy test was falsely negative.
• The pregnancy is extremely early.
• Another medical condition is causing the symptoms.
• The woman has a cryptic pregnancy.
• There is an ectopic pregnancy or another urgent condition requiring immediate treatment.

This systematic approach minimizes diagnostic errors and ensures timely, appropriate care.

STEP ONE: COMPREHENSIVE MEDICAL HISTORY

The first step is obtaining a detailed medical history.

Doctors ask questions about:

• The date of the last menstrual period.
• Regularity of menstrual cycles.
• Previous pregnancies.
• Miscarriages.
• Ectopic pregnancies.
• Fertility treatments.
• Contraceptive use.
• Sexual activity.
• Previous gynecological conditions.
• Current medications.
• Breastfeeding status.
• Perimenopausal symptoms.
• Family history of reproductive disorders.

A thorough history often provides the first clues to the diagnosis.

ASSESSMENT OF PREGNANCY SYMPTOMS

Doctors carefully evaluate symptoms such as:

• Missed periods.
• Nausea.
• Vomiting.
• Breast tenderness.
• Breast enlargement.
• Fatigue.
• Frequent urination.
• Food cravings.
• Abdominal enlargement.
• Perceived fetal movements.
• Weight changes.

Although these symptoms may suggest pregnancy, none of them alone confirms the diagnosis.

PHYSICAL EXAMINATION

A comprehensive examination includes assessment of:

• Blood pressure.
• Pulse.
• Respiratory rate.
• Temperature.
• Weight.
• Body Mass Index (BMI).
• Thyroid gland.
• Abdomen.
• Breasts.
• Pelvic organs when appropriate.

The examination helps identify pregnancy as well as other medical conditions that may mimic pregnancy.

ABDOMINAL EXAMINATION

Doctors assess:

• Abdominal enlargement.
• Uterine size.
• Tenderness.
• Pelvic masses.
• Fluid accumulation.

As pregnancy advances, uterine enlargement becomes easier to recognize.

However, obesity, uterine fibroids, ovarian masses, or abdominal distension may complicate the examination.

BREAST EXAMINATION

Breast examination evaluates:

• Enlargement.
• Tenderness.
• Milk production.
• Nipple discharge.
• Skin changes.
• Breast lumps.

These findings help determine whether hormonal changes are occurring and whether additional investigations are required.

REPEATING THE URINE PREGNANCY TEST

If the initial test was performed:

• Too early.
• With diluted urine.
• Incorrectly.

Doctors may recommend repeating it.

For the most reliable result:

• Use the first urine passed in the morning.
• Follow the manufacturer's instructions carefully.
• Check that the test has not expired.
• Read the result within the recommended time.

Repeating the test after 48–72 hours may detect a pregnancy that was previously too early to identify.

QUANTITATIVE SERUM β-HUMAN CHORIONIC GONADOTROPIN (β-hCG)

If pregnancy remains a possibility despite a negative urine test, doctors usually request a quantitative serum β-hCG test.

This blood test:

• Detects much lower levels of hCG.
• Confirms pregnancy earlier than most urine tests.
• Measures the exact concentration of the hormone.
• Helps determine whether pregnancy is progressing.

It is considered one of the most valuable investigations in uncertain cases.

SERIAL β-hCG MEASUREMENTS

A single β-hCG value provides useful information, but repeated measurements are often even more informative.

Doctors may repeat the blood test after approximately 48 hours to observe the trend.

They assess whether hCG levels are:

• Increasing appropriately.
• Increasing more slowly than expected.
• Plateauing.
• Declining.

These patterns help evaluate early pregnancy development and identify conditions such as ectopic pregnancy or early pregnancy loss when interpreted together with clinical findings and ultrasound.

ULTRASOUND EXAMINATION

Ultrasound is the definitive imaging method for confirming or excluding pregnancy.

Unlike pregnancy tests, ultrasound directly visualizes pelvic structures.

It can identify:

• Gestational sac.
• Yolk sac.
• Embryo.
• Fetal heartbeat.
• Placenta.
• Amniotic fluid.
• Ovaries.
• Uterus.

Ultrasound often resolves diagnostic uncertainty.

TRANSVAGINAL ULTRASOUND

During early pregnancy, transvaginal ultrasound provides excellent visualization of:

• Early gestational sac.
• Embryo.
• Cardiac activity.
• Cervix.
• Ovaries.

It is particularly valuable during the first trimester.

TRANSABDOMINAL ULTRASOUND

As pregnancy progresses, transabdominal ultrasound becomes increasingly useful.

Doctors assess:

• Fetal growth.
• Placental position.
• Fetal movements.
• Amniotic fluid volume.
• Umbilical cord.
• Maternal pelvic anatomy.

ASSESSMENT OF FETAL HEARTBEAT

The presence of fetal cardiac activity confirms fetal viability at the time of the examination.

Doctors evaluate:

• Heart rate.
• Rhythm.
• Overall fetal wellbeing.

Continuous fetal monitoring may be indicated later in pregnancy.

EXCLUDING ECTOPIC PREGNANCY

One of the most important responsibilities is excluding ectopic pregnancy.

Doctors become particularly concerned when a woman has:

• Persistent pelvic pain.
• One-sided abdominal pain.
• Vaginal bleeding.
• Shoulder-tip pain.
• Fainting.
• Positive or uncertain pregnancy tests without a confirmed intrauterine pregnancy.

Prompt diagnosis is essential because ectopic pregnancy may become life-threatening.

DIFFERENTIAL DIAGNOSIS

Pregnancy-like symptoms with a negative urine pregnancy test may result from several conditions.

Doctors consider:

• Very early pregnancy.
• Cryptic pregnancy.
• Ectopic pregnancy.
• Pregnancy of Unknown Location.
• Early pregnancy loss.
• False pregnancy (pseudocyesis).
• Polycystic Ovary Syndrome (PCOS).
• Thyroid disorders.
• Hyperprolactinemia.
• Perimenopause.
• Ovarian cysts.
• Uterine fibroids.
• Gastrointestinal disorders.
• Medication-related hormonal changes.

Each condition requires a different management strategy.

TREATMENT

Treatment depends entirely on the underlying diagnosis.

There is no single treatment for a negative pregnancy test with pregnancy-like symptoms.

Management may include:

IF PREGNANCY IS CONFIRMED

• Early antenatal care.
• Nutritional counseling.
• Prenatal vitamins.
• Ultrasound follow-up.
• Routine obstetric monitoring.

IF ECTOPIC PREGNANCY IS DIAGNOSED

Treatment may involve:

• Medication in carefully selected cases.
• Minimally invasive surgery or emergency surgery when clinically indicated.

The choice depends on the woman's condition and the characteristics of the ectopic pregnancy.

IF FALSE PREGNANCY (PSEUDOCYESIS) IS DIAGNOSED

Management focuses on:

• Compassionate communication.
• Treatment of underlying hormonal disorders if present.
• Psychological support.
• Counseling.
• Follow-up care.

IF ANOTHER MEDICAL CONDITION IS IDENTIFIED

Treatment targets the specific diagnosis, such as thyroid disease, PCOS, hyperprolactinemia, or other endocrine or gynecological disorders.

LIFESTYLE MODIFICATIONS

Women should support their reproductive health by:

• Eating a balanced diet.
• Maintaining a healthy body weight.
• Exercising regularly as appropriate.
• Getting adequate sleep.
• Managing stress effectively.
• Avoiding smoking.
• Avoiding recreational drugs.
• Limiting alcohol consumption.
• Attending scheduled medical appointments.

Healthy habits support overall wellbeing but do not replace medical evaluation.

ARE THERE HOME REMEDIES?

There are no scientifically proven home remedies that can:

• Confirm pregnancy.
• Exclude pregnancy.
• Treat cryptic pregnancy.
• Correct a false-negative pregnancy test.
• Replace ultrasound or blood β-hCG testing.

Women should avoid relying on unverified herbal remedies or internet myths when pregnancy remains uncertain.

PSYCHOLOGICAL SUPPORT

Receiving conflicting pregnancy test results can be emotionally distressing.

Some women experience:

• Anxiety.
• Confusion.
• Fear.
• Frustration.
• Emotional exhaustion.

Clear communication, reassurance, and professional counseling may be beneficial while investigations are ongoing.

PROGNOSIS

The outlook depends on the final diagnosis.

Women with confirmed cryptic pregnancy generally have good outcomes when appropriate antenatal care begins promptly.

Women with false-negative urine tests caused by early testing or technical factors usually experience no long-term harm once pregnancy is recognized.

Early diagnosis remains the key to protecting maternal and fetal health.

COMPREHENSIVE CONCLUSION 

When pregnancy symptoms persist despite a negative urine pregnancy test, doctors rely on a comprehensive, evidence-based evaluation rather than a single test result. Careful history taking, physical examination, repeat urine testing when appropriate, quantitative serum β-human chorionic gonadotropin (β-hCG), serial hormone measurements, and ultrasound imaging provide the most accurate pathway to diagnosis. This systematic approach allows clinicians to identify cryptic pregnancy, exclude potentially life-threatening conditions such as ectopic pregnancy, and diagnose other endocrine or gynecological disorders that may mimic pregnancy. Individualized treatment, healthy lifestyle measures, emotional support, and timely follow-up help ensure the best possible outcomes for women facing diagnostic uncertainty.

CAN FALSE-NEGATIVE PREGNANCY TESTS BE PREVENTED?

Although no diagnostic test is completely free from limitations, many false-negative pregnancy test results can be avoided through proper testing techniques, appropriate timing, and timely medical evaluation.

The most effective strategy is not simply repeating home pregnancy tests but ensuring that persistent pregnancy symptoms are assessed by qualified healthcare professionals using the appropriate investigations.

Women should remember that a single negative urine pregnancy test does not always provide the final answer when pregnancy is still clinically suspected.

DO NOT TEST TOO EARLY

Testing too soon after conception is the most common reason for a false-negative result.

Pregnancy tests require sufficient human chorionic gonadotropin (hCG) to be present before they become positive.

If testing is performed before adequate hCG has accumulated:

• Pregnancy may exist.
• The urine test may remain negative.

Waiting until after a missed menstrual period—or repeating the test after 48 to 72 hours if pregnancy is still suspected—improves accuracy.

USE FIRST-MORNING URINE

The first urine passed after waking is generally the most concentrated.

It usually contains the highest concentration of urinary hCG.

Testing with first-morning urine:

• Improves sensitivity.
• Reduces false-negative results caused by diluted urine.
• Is especially useful during very early pregnancy.

FOLLOW THE INSTRUCTIONS CAREFULLY

Home pregnancy tests should always be used according to the manufacturer's instructions.

Important recommendations include:

• Check the expiration date.
• Use the recommended amount of urine.
• Read the result within the specified time.
• Do not interpret the result after the recommended reading window.
• Store the test kit properly.

Correct technique improves reliability.

REPEAT THE TEST WHEN APPROPRIATE

If pregnancy symptoms continue despite a negative urine test:

Doctors may advise:

• Repeating the test after several days.
• Using first-morning urine.
• Obtaining a quantitative serum β-hCG test.
• Performing an ultrasound when indicated.

Repeat testing should never replace medical evaluation when concerning symptoms are present.

SEEK EARLY MEDICAL EVALUATION

Women should consult a healthcare professional if they have:

• Persistent missed periods.
• Recurrent nausea.
• Breast tenderness.
• Positive pregnancy symptoms.
• Persistent abdominal enlargement.
• Vaginal bleeding with pregnancy symptoms.
• Severe pelvic pain.

Early assessment allows timely diagnosis of:

• Cryptic pregnancy.
• Ectopic pregnancy.
• Pregnancy of Unknown Location.
• Hormonal disorders.
• Gynecological conditions.

ATTEND EARLY ANTENATAL CARE ONCE PREGNANCY IS CONFIRMED

Once pregnancy is diagnosed, early prenatal care provides numerous benefits.

Healthcare professionals can:

• Estimate gestational age.
• Confirm fetal viability.
• Assess maternal health.
• Identify multiple pregnancy.
• Detect complications early.
• Provide nutritional counseling.
• Recommend appropriate prenatal supplements.
• Monitor fetal growth.

Timely antenatal care improves outcomes for both mother and baby.

MANAGE UNDERLYING MEDICAL CONDITIONS

Women with chronic conditions should receive appropriate treatment before and during pregnancy.

Examples include:

• Polycystic Ovary Syndrome (PCOS).
• Thyroid disorders.
• Diabetes mellitus.
• Hyperprolactinemia.
• Hypertension.
• Obesity.

Good control of these conditions improves reproductive health and facilitates earlier pregnancy recognition.

MAINTAIN A HEALTHY LIFESTYLE

Healthy lifestyle habits support fertility, pregnancy, and overall wellbeing.

Women should:

• Eat a balanced diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats.
• Maintain a healthy body weight.
• Stay physically active according to medical advice.
• Get adequate sleep.
• Stay well hydrated.
• Avoid smoking.
• Avoid recreational drugs.
• Limit alcohol consumption.

While these measures do not prevent false-negative tests, they contribute to healthier pregnancies.

MYTHS VERSUS FACTS

Understanding the science behind pregnancy testing helps dispel common misconceptions.

MYTH 1: A NEGATIVE PREGNANCY TEST ALWAYS MEANS YOU ARE NOT PREGNANT

FACT

Most negative pregnancy tests correctly indicate that pregnancy is absent.

However, false-negative results can occur, particularly if the test is performed too early, urine is diluted, instructions are not followed correctly, or other uncommon factors interfere with detection.

Persistent pregnancy symptoms require further medical evaluation.

MYTH 2: CRYPTIC PREGNANCY MEANS THE BABY IS INVISIBLE

FACT

No.

The pregnancy is real.

The fetus develops normally.

The pregnancy is called "cryptic" because it is recognized late, not because the baby is hidden from ultrasound.

MYTH 3: IF A HOME TEST IS NEGATIVE, THERE IS NO NEED TO SEE A DOCTOR

FACT

If symptoms strongly suggest pregnancy or if concerning symptoms such as pain or bleeding occur, medical evaluation is important even after a negative home test.

Doctors may perform quantitative serum β-hCG testing and ultrasound to clarify the diagnosis.

MYTH 4: HOME REMEDIES CAN CONFIRM PREGNANCY

FACT

Traditional methods involving toothpaste, sugar, salt, bleach, baking soda, soap, vinegar, or other household substances have no scientific validity for diagnosing pregnancy.

Only validated medical tests should be used.

MYTH 5: THE HIGH-DOSE HOOK EFFECT IS A COMMON CAUSE OF NEGATIVE TESTS

FACT

The high-dose hook effect is extremely rare.

The vast majority of false-negative pregnancy tests result from:

• Testing too early.
• Delayed ovulation.
• Delayed implantation.
• Diluted urine.
• User-related factors.

MYTH 6: SYMPTOMS ALONE CAN CONFIRM PREGNANCY

FACT

Symptoms such as nausea, fatigue, breast tenderness, bloating, or missed periods may occur in many medical conditions.

Pregnancy should always be confirmed with appropriate laboratory testing and, when indicated, ultrasound.

FREQUENTLY ASKED QUESTIONS (FAQs)

CAN A BLOOD PREGNANCY TEST BE POSITIVE WHEN A URINE TEST IS NEGATIVE?

Yes.

Because quantitative serum β-hCG testing is more sensitive than most urine tests, it may detect pregnancy earlier, particularly in very early gestation.

HOW LONG SHOULD I WAIT BEFORE REPEATING A NEGATIVE TEST?

If pregnancy remains possible and menstruation has not started, many healthcare professionals recommend repeating the test after 48–72 hours or seeking medical evaluation, especially if symptoms persist.

CAN STRESS CAUSE A FALSE-NEGATIVE PREGNANCY TEST?

Stress itself does not directly cause a pregnancy test to become negative.

However, stress can influence menstrual cycles and ovulation, making pregnancy timing more difficult to estimate and potentially leading to testing too early.

CAN MEDICATIONS CAUSE FALSE-NEGATIVE RESULTS?

Most commonly used medications do not cause false-negative pregnancy tests.

However, certain medications and medical conditions may affect menstrual cycles or pregnancy symptoms.

Women should always inform their healthcare provider about all medications and supplements they are taking.

WHEN SHOULD I SEEK EMERGENCY MEDICAL CARE?

Seek urgent medical attention immediately if pregnancy symptoms are accompanied by:

• Severe one-sided pelvic pain.
• Heavy vaginal bleeding.
• Shoulder-tip pain.
• Fainting.
• Persistent dizziness.
• Fever.
• Severe abdominal pain.
• Persistent vomiting.
• Signs of shock.

These symptoms may indicate ectopic pregnancy or another medical emergency.

KEY TAKE-HOME MESSAGES

• Cryptic pregnancy is a genuine pregnancy that remains unrecognized until later than expected.
• Most home pregnancy tests are highly accurate when used correctly.
• Testing too early is the most common cause of a false-negative result.
• Late ovulation, delayed implantation, diluted urine, improper testing technique, and low-sensitivity test kits may also contribute.
• The high-dose hook effect is a very rare explanation for false-negative results.
• Persistent pregnancy symptoms should never be dismissed because of one negative urine test.
• Quantitative serum β-hCG testing is more sensitive than most urine tests.
• Ultrasound is the definitive imaging method for confirming pregnancy.
• Ectopic pregnancy must always be excluded when symptoms suggest pregnancy but the diagnosis remains uncertain.
• Early medical evaluation and antenatal care improve maternal and fetal outcomes.

COMPREHENSIVE FINAL CONCLUSION

A negative home pregnancy test does not always exclude pregnancy, particularly when testing is performed too early or under circumstances that reduce the ability of the test to detect human chorionic gonadotropin (hCG). Cryptic pregnancy is a genuine pregnancy that may remain unrecognized because of subtle symptoms, irregular ovulation, bleeding mistaken for menstruation, delayed implantation, or, in uncommon situations, false-negative test results. Modern obstetric practice emphasizes that pregnancy diagnosis should never rely solely on one urine test. Instead, healthcare professionals integrate clinical history, physical examination, repeat testing when appropriate, quantitative serum β-human chorionic gonadotropin (β-hCG), and ultrasound imaging to establish an accurate diagnosis. Timely recognition of pregnancy allows early antenatal care, improves maternal and fetal outcomes, and ensures that potentially life-threatening conditions such as ectopic pregnancy are identified without delay.

ABOUT THE AUTHOR

Dr. Abiazim Chima is a healthcare professional, maternal health advocate, public health educator, and founder of Mother Healthcare. He is committed to promoting evidence-based education in obstetrics, gynecology, reproductive medicine, fertility, maternal health, diagnostic ultrasound, newborn care, preventive medicine, and public health. Through comprehensive, research-informed publications, he equips patients, healthcare professionals, students, educators, and researchers with reliable, compassionate, and scientifically accurate medical information that supports informed healthcare decisions and advances maternal and reproductive health.

DISCLAIMER

This article is intended solely for educational and informational purposes and should not replace professional medical advice, diagnosis, or treatment. A negative home pregnancy test does not always exclude pregnancy, particularly in the earliest stages or under specific testing conditions. Women with persistent pregnancy symptoms, missed periods, abnormal vaginal bleeding, severe abdominal pain, shoulder-tip pain, fainting, fever, or any concerning symptoms should seek prompt evaluation from a qualified healthcare professional. Medical decisions should always be based on a comprehensive clinical assessment and appropriate investigations, including laboratory testing and ultrasound when indicated.

RELATED MOTHER HEALTHCARE ARTICLES

• What Is Cryptic Pregnancy?
• What Is the Difference Between False Pregnancy and Cryptic Pregnancy?
• What Causes a False-Negative Pregnancy Test?
• Can a Blood Pregnancy Test Be Positive Before a Urine Test?
• Why Do I Feel Pregnant but Every Test Is Negative?
• Can a Woman Be Pregnant and Still Have Bleeding Every Month?
• What Does Pregnancy of Unknown Location Mean?
• Why Is My Pregnancy Test Positive but Nothing Is Seen on Ultrasound?
• Why Do Doctors Repeat Early Pregnancy Scans Instead of Giving an Answer Immediately?
• How Is Pregnancy Confirmed by Ultrasound?
• Can PCOS Delay a Positive Pregnancy Test?
• Can Hormonal Imbalance Cause Pregnancy-Like Symptoms?
• Can Stress Make a Woman Feel Pregnant?
• What Is False Pregnancy (Pseudocyesis)?
• How Do Doctors Confirm False Pregnancy?
• What Does an Empty Gestational Sac Mean?
• Can You Ovulate Later Than Expected?
• What Causes Irregular Menstrual Cycles?
• Can Ectopic Pregnancy Cause a Negative Pregnancy Test?
• When Should I Repeat a Pregnancy Test?

RECOMMENDED ACADEMIC REFERENCES

This article is based on current evidence and recommendations from internationally recognized authorities, including:

• American College of Obstetricians and Gynecologists (ACOG)
• Royal College of Obstetricians and Gynaecologists (RCOG)
• National Institute for Health and Care Excellence (NICE)
• World Health Organization (WHO)
• American Society for Reproductive Medicine (ASRM)
• European Society of Human Reproduction and Embryology (ESHRE)
• Society for Maternal-Fetal Medicine (SMFM)
• American Institute of Ultrasound in Medicine (AIUM)
• American Journal of Obstetrics & Gynecology (AJOG)
• Obstetrics & Gynecology
• Human Reproduction
• Fertility and Sterility
• The Journal of Clinical Endocrinology & Metabolism
• The BMJ
• The Lancet
• The New England Journal of Medicine (NEJM)

END OF MASTER ARTICLE

WHY WOULD A PREGNANCY TEST BE NEGATIVE IN A CRYPTIC PREGNANCY?

This comprehensive Mother Healthcare cornerstone article explains why a real pregnancy may occasionally be associated with an initial negative pregnancy test, while emphasizing that such situations are uncommon and require careful medical evaluation. It explores the biology of hCG production, the limitations of urine pregnancy testing, the role of delayed ovulation, delayed implantation, irregular menstrual cycles, and rare laboratory phenomena such as the high-dose hook effect. It also outlines evidence-based diagnostic pathways using quantitative serum β-hCG and ultrasound, highlights conditions that may mimic or complicate pregnancy recognition, and provides practical guidance for patients and healthcare professionals. By combining scientific accuracy with compassionate patient education, this article serves as a valuable resource for expectant mothers, obstetricians, gynecologists, family physicians, emergency physicians, endocrinologists, sonographers, nurses, midwives, medical students, educators, and researchers.