Prenatal Care — MCQs

Prenatal Care Indian Medical PG Practice Questions and MCQs

Question 71: What is Osiander's sign?

A. Pulsation in the lateral vaginal fornix (Correct Answer)
B. Bluish colour change in the vagina
C. Softening of the cervix
D. On bimanual palpation the fingers can be approximated as if nothing is in between

Explanation: **Explanation:** **Osiander’s sign** is a clinical sign of early pregnancy, typically appearing around the **8th week** of gestation. It is characterized by the perception of **increased pulsations in the lateral vaginal fornices** during a pelvic examination. This occurs due to the marked increase in vascularity and blood flow to the uterus (hyperemia) to support the developing fetus. **Analysis of Options:** * **Option A (Correct):** Osiander’s sign is specifically defined as the increased pulsation felt through the lateral fornices, resulting from the hypertrophy of the uterine arteries. * **Option B (Incorrect):** This describes **Chadwick’s sign** (or Jacquemier’s sign), which is a bluish discoloration of the cervix, vagina, and labia due to venous congestion. * **Option C (Incorrect):** This describes **Goodell’s sign**, which is the significant softening of the cervix (often compared to the feel of the lips rather than the nose) occurring around the 6th week. * **Option D (Incorrect):** This describes **Hegar’s sign**, where the softening of the uterine isthmus allows the fingers of the bimanual exam to nearly approximate. **High-Yield Clinical Pearls for NEET-PG:** * **Piskacek’s Sign:** Asymmetrical enlargement of the uterus if implantation occurs near one of the cornua. * **Palmer’s Sign:** Rhythmic uterine contractions felt during a bimanual examination (early pregnancy). * **Timeline:** Most of these "probable" signs of pregnancy (Hegar, Goodell, Chadwick, Osiander) appear between **6 to 10 weeks** of gestation. * **Vascularity:** Remember that Osiander’s sign is a direct result of the **uterine artery** supplying more blood to the gravid uterus.

Question 72: What is the detection rate of Down syndrome with first-trimester screening using NT, PAPP-A, and hCG?

A. 64-70%
B. 80-84% (Correct Answer)
C. 94-96%
D. 99%

Explanation: **Explanation:** The correct answer is **80-84%**. This screening method, known as the **Combined Test**, is performed between 11 and 13+6 weeks of gestation. It utilizes three markers: Nuchal Translucency (NT) via ultrasound, and maternal serum levels of Pregnancy-Associated Plasma Protein-A (PAPP-A) and free β-hCG. In a fetus with Down syndrome, the NT is typically increased, PAPP-A is decreased, and hCG is increased. When these three markers are combined, the detection rate for Trisomy 21 is approximately 82-87% (commonly cited as 80-84% in standard textbooks like Williams Obstetrics) for a 5% false-positive rate. **Analysis of Incorrect Options:** * **A (64-70%):** This is the detection rate for **NT alone**. While NT is the most sensitive ultrasound marker, it lacks the diagnostic power of the combined biochemical screen. * **C (94-96%):** This represents the detection rate of the **Integrated Test** (combining first-trimester NT/PAPP-A with the second-trimester Quadruple screen) or the **Sequential screening** protocols. * **D (99%):** This is the detection rate for **Cell-free DNA (cfDNA)** screening (Non-Invasive Prenatal Testing - NIPT), which is currently the most sensitive screening tool available but is not the "Combined Test." **High-Yield Clinical Pearls for NEET-PG:** * **Best time for NT:** 11 weeks to 13 weeks 6 days (CRL 45mm to 84mm). * **Down Syndrome Biochemical Profile:** ↓ PAPP-A, ↑ hCG (First Trimester); ↓ AFP, ↓ uE3, ↑ hCG, ↑ Inhibin A (Second Trimester Quad Screen). * **Nasal Bone:** Absence of the nasal bone in the first trimester significantly increases the risk of Down syndrome and is often added to the combined test to increase the detection rate to ~90%.

Question 73: What is the earliest ultrasound sign of pregnancy in a transabdominal ultrasound scan?

A. Visible gestational sac
B. Apparent embryonic structures
C. Fundal endometrial thickening (Correct Answer)
D. Identifiable cardiac movements

Explanation: **Explanation:** The earliest sonographic sign of pregnancy, particularly on a transabdominal scan (TAS), is **fundal endometrial thickening**. This occurs due to the decidual reaction—the hypertrophy and increased vascularity of the endometrial lining in preparation for implantation. This "decidual sign" appears as a thickened, echogenic endometrium before a distinct gestational sac can be visualized. **Analysis of Options:** * **A. Visible gestational sac:** While the gestational sac is the first *definitive* sign of an intrauterine pregnancy, it typically appears around 5 weeks of gestation on TAS (4.5 weeks on TVS). Endometrial thickening precedes this. * **B. Apparent embryonic structures:** The fetal pole (embryo) only becomes visible within the gestational sac at approximately 6 weeks of gestation. * **C. Fundal endometrial thickening (Correct):** This is the earliest non-specific sign, appearing in the late luteal phase/early pregnancy (approx. 3-4 weeks). * **D. Identifiable cardiac movements:** This is the first sign of a *viable* pregnancy, usually detected when the embryo reaches a crown-rump length (CRL) of 5mm (around 6-6.5 weeks). **High-Yield Clinical Pearls for NEET-PG:** * **Double Decidual Sign:** Two concentric echogenic rings surrounding the gestational sac; it helps differentiate a true gestational sac from a "pseudogestational sac" seen in ectopic pregnancy. * **Discriminatory Zone:** The serum β-hCG level at which a gestational sac should be visible (1500–2000 mIU/ml for TVS; 6500 mIU/ml for TAS). * **Mean Sac Diameter (MSD):** A gestational sac should be visible via TVS when the MSD is 2–3 mm.

Question 74: What is the most common cause of urinary tract infection in pregnancy?

A. Proteus mirabilis
B. Group B beta-hemolytic streptococcus
C. E. coli (Correct Answer)
D. Klebsiella

Explanation: **Explanation:** **Correct Answer: C. E. coli** *Escherichia coli* is the most common causative organism for Urinary Tract Infections (UTIs) in both pregnant and non-pregnant women, accounting for approximately **70–90% of cases**. In pregnancy, physiological changes such as progesterone-induced ureteral dilatation (hydroureter), decreased bladder tone, and glycosuria create an environment conducive to bacterial growth. *E. coli*, a commensal of the gastrointestinal tract, ascends the short female urethra to colonize the urinary tract. Its virulence is enhanced by **P-fimbriae**, which allow the bacteria to adhere to the uroepithelium. **Analysis of Incorrect Options:** * **A. Proteus mirabilis:** While a known cause of UTI, it is less common than *E. coli*. It is classically associated with **struvite (staghorn) stones** due to its urease-producing ability, which increases urinary pH. * **B. Group B Streptococcus (GBS):** GBS colonization is significant in pregnancy due to the risk of neonatal sepsis, but it is a less frequent cause of UTI compared to Gram-negative bacilli. Its presence in urine (even at low colony counts) indicates heavy vaginal colonization and necessitates intrapartum antibiotic prophylaxis. * **D. Klebsiella:** This is the second most common Gram-negative organism causing UTIs in pregnancy, but it lags significantly behind *E. coli* in prevalence. **High-Yield Clinical Pearls for NEET-PG:** * **Asymptomatic Bacteriuria (ASB):** Defined as >10⁵ CFU/mL in two consecutive clean-catch samples (or one catheterized sample) in an asymptomatic patient. It **must** be screened for and treated in pregnancy to prevent progression to pyelonephritis (20–40% risk if untreated). * **Most common site of Pyelonephritis:** Right side (due to dextrorotation of the uterus and the protective effect of the sigmoid colon on the left ureter). * **Drug of Choice:** Nitrofurantoin (avoid near term due to risk of neonatal hemolysis/G6PD) or Amoxicillin-Clavulanate.

Question 75: At what gestational age can the earliest fetal heart activity be detected?

A. 6.0-6.5 weeks (Correct Answer)
B. 6.5-7 weeks
C. 7.1-7.5 weeks
D. 8 weeks

Explanation: **Explanation:** The detection of fetal heart activity is a critical milestone in early pregnancy, serving as the definitive sign of a viable intrauterine pregnancy. **Why Option A is Correct:** The fetal heart is the first functional organ to develop. Spontaneous rhythmic contractions begin around the 22nd day of development (approximately 5 weeks of gestation). However, these are not consistently visible on imaging immediately. Using **Transvaginal Sonography (TVS)**, fetal heart activity can typically be detected when the Crown-Rump Length (CRL) reaches 1–2 mm, which corresponds to a gestational age of **6.0 to 6.5 weeks**. At this stage, the heart rate is relatively slow (approx. 100-110 bpm) before increasing. **Analysis of Incorrect Options:** * **Options B & C (6.5–7.5 weeks):** While heart activity is clearly visible during this window, it is not the *earliest* point of detection. By 7 weeks, the heart rate typically peaks around 175 bpm. * **Option D (8 weeks):** This is the timeframe when fetal heart activity can usually be detected via **Transabdominal Sonography (TAS)**. TAS has lower resolution than TVS and requires a larger embryo and more advanced gestation for accurate detection. **NEET-PG High-Yield Pearls:** * **TVS vs. TAS:** TVS can detect pregnancy milestones about 1 week earlier than TAS. * **Discriminatory Zone:** Fetal heart activity should always be visible by TVS when the CRL is **>7 mm**. If absent at this size, it suggests pregnancy failure (Missed Abortion). * **Mean Sac Diameter (MSD):** A yolk sac should be visible when the MSD is 20 mm (TVS); an embryo with a heartbeat should be visible when the MSD is **>25 mm**. * **Doppler:** While M-mode is used to document the rate, pulse-wave Doppler is generally avoided in the first trimester to prevent thermal bioeffects on the developing embryo.

Question 76: An obstetrician sees a pregnant patient who was exposed to rubella virus in the eighteenth week of pregnancy. She does not remember getting a rubella vaccination. What is the best immediate course of action?

A. Terminate the pregnancy
B. Order a rubella antibody titer to determine immune status (Correct Answer)
C. Reassure the patient because rubella is not a problem until after the thirtieth week
D. Administer rubella immune globulin

Explanation: The management of rubella exposure in pregnancy depends on the mother’s immune status and the gestational age at exposure. **Explanation of the Correct Answer:** The immediate priority is to determine if the mother is already immune. Many adults have immunity through childhood vaccination or prior subclinical infection. A **Rubella IgG antibody titer** should be ordered: * **If IgG is positive:** The patient is immune, and there is no risk of Congenital Rubella Syndrome (CRS). * **If IgG is negative:** The patient is susceptible. A second sample should be taken 2–3 weeks later to check for seroconversion (IgM/IgG), which would indicate an acute infection. **Analysis of Incorrect Options:** * **Option A:** Termination is not indicated without confirming maternal infection and assessing fetal risk. Furthermore, the risk of CRS decreases significantly after the first trimester. * **Option C:** This is factually incorrect. Rubella is most dangerous in the **first trimester** (up to 80% risk of CRS). While the risk drops after 16–18 weeks, exposure in the eighteenth week still requires investigation. * **Option D:** Rubella immune globulin does not reliably prevent fetal infection and is only considered if a susceptible woman refuses termination after a confirmed exposure. **NEET-PG High-Yield Pearls:** * **Maximum Risk:** The highest risk for CRS is during the first 12 weeks of gestation. * **Classic Triad of CRS:** Sensorineural deafness (most common), Cataracts (salt-and-pepper retinopathy), and Cardiac defects (Patent Ductus Arteriosus). * **Vaccination:** The Rubella vaccine (RA 27/3 strain) is a **live-attenuated vaccine** and is **contraindicated during pregnancy**. Women should avoid pregnancy for 1 month (28 days) after receiving the MMR vaccine. * **Postpartum:** If a pregnant woman is found to be non-immune, she should be vaccinated in the immediate postpartum period.

Question 77: Which of the following is considered the definitive sign of pregnancy?

A. Human chorionic gonadotropin (hCG) estimation
B. Quickening (fetal movements felt by the mother)
C. Chadwick sign (bluish discoloration of cervix and vagina)
D. Fetal skeleton visualized on X-ray (Correct Answer)

Explanation: In Obstetrics, signs of pregnancy are categorized into three groups: **Presumptive, Probable, and Positive (Definitive).** ### 1. Why the Correct Answer is Right **Fetal skeleton visualized on X-ray** is a **Positive (Definitive) sign** because it provides objective, undeniable evidence of a fetus. Positive signs are those that cannot be attributed to any other physiological or pathological condition. Other definitive signs include the visualization of the fetus by ultrasound and the detection of fetal heart sounds (FHS) by Doppler or fetoscope. *Note: While X-rays are avoided in modern practice due to radiation risks, they remain a classic textbook definitive sign.* ### 2. Analysis of Incorrect Options * **A. hCG estimation:** This is a **Probable sign**. While highly sensitive, elevated hCG can occur in pathological conditions like Gestational Trophoblastic Neoplasia (Molar pregnancy) or certain germ cell tumors. * **B. Quickening:** This is a **Presumptive sign**. It is a subjective sensation felt by the mother (usually at 18–20 weeks in primigravida). It can be confused with intestinal peristalsis or "pseudocyesis." * **C. Chadwick sign:** This is a **Probable sign**. The bluish discoloration is due to pelvic congestion. It can occasionally be seen in conditions causing intense pelvic hyperemia, such as pelvic tumors or endometriosis. ### 3. NEET-PG High-Yield Pearls * **Earliest Definitive Sign:** Visualization of the gestational sac via Transvaginal Ultrasound (TVS) at **4.5 to 5 weeks**. * **Hegar’s Sign:** Softening of the lower uterine isthmus (Probable sign), best felt between **6–10 weeks**. * **Fetal Heart Sounds:** Can be detected by TVS at **6 weeks**, Doppler at **10–12 weeks**, and Pinard’s fetoscope at **18–20 weeks**. * **Rule of Thumb:** If the sign is subjective (mother feels it), it's *Presumptive*. If the doctor sees/feels it but it could be a tumor, it's *Probable*. If it’s definitely a baby, it's *Positive*.

Question 78: In Down syndrome, which of the following markers is NOT typically measured in the second-trimester quadruple screening test performed between 14-20 weeks of gestation?

A. Alpha-fetoprotein
B. Human chorionic gonadotropin (hCG)
C. Inhibin A
D. Progesterone (Correct Answer)

Explanation: The **Quadruple Screening Test** (Quad Screen) is a prenatal screening tool performed between **15 and 20 weeks** (ideally 16–18 weeks) of gestation to assess the risk of chromosomal abnormalities like Down syndrome (Trisomy 21) and Trisomy 18, as well as neural tube defects. ### Why Progesterone is the Correct Answer: **Progesterone** is not a component of the Quad screen. While it is essential for maintaining pregnancy, its levels do not serve as a reliable predictive marker for fetal aneuploidy. The fourth marker added to the "Triple Screen" to create the "Quad Screen" is **Inhibin A**, which significantly increases the sensitivity for detecting Down syndrome. ### Explanation of Incorrect Options (The Quad Markers): In a pregnancy affected by **Down syndrome**, the markers typically show the following patterns: * **Alpha-fetoprotein (AFP):** Levels are **decreased**. (Low AFP is also seen in Trisomy 18). * **Human chorionic gonadotropin (hCG):** Levels are **increased**. * **Inhibin A:** Levels are **increased**. * **Unconjugated Estriol (uE3):** (Not listed in options but the 4th marker) Levels are **decreased**. ### High-Yield Clinical Pearls for NEET-PG: * **Mnemonic for Down Syndrome (HI):** **H**CG and **I**nhibin A are **HI**gh; the others (AFP and uE3) are low. * **Trisomy 18 (Edwards Syndrome):** All markers (AFP, hCG, uE3) are typically **decreased**. * **Neural Tube Defects (NTD):** Characterized by **elevated AFP** levels. * **First Trimester Screening (11–13.6 weeks):** Uses PAPP-A (decreased), β-hCG (increased), and Nuchal Translucency (increased) for Down syndrome. * **Confirmatory Test:** Screening tests are not diagnostic. If the Quad screen is positive, definitive diagnosis requires **Amniocentesis** or **CVS**.

Question 79: What is the marker for neural tube defects?

A. PAPP-A
B. hCG
C. Estriol
D. Acetylcholinesterase (Correct Answer)

Explanation: **Explanation:** The correct answer is **Acetylcholinesterase (AChE)**. Neural tube defects (NTDs), such as anencephaly and spina bifida, occur when the neural tube fails to close during embryogenesis. This results in an open communication between the fetal central nervous system and the amniotic fluid. **Why it is correct:** When an open NTD is present, **Alpha-fetoprotein (AFP)** leaks into the amniotic fluid and maternal serum. However, AFP is a screening marker and can be elevated in other conditions (e.g., abdominal wall defects, multiple gestations). **Acetylcholinesterase (AChE)** is a neurotransmitter enzyme that leaks specifically from exposed neural tissue. Its presence in the amniotic fluid is a **confirmatory diagnostic marker** for open NTDs, as it is not typically found in amniotic fluid unless neural tissue is exposed. **Analysis of Incorrect Options:** * **A. PAPP-A (Pregnancy-associated plasma protein A):** Used in first-trimester screening. Low levels are associated with Down syndrome (Trisomy 21) and fetal growth restriction. * **B. hCG (human Chorionic Gonadotropin):** Elevated levels are seen in Down syndrome (second-trimester Quadruple screen) and gestational trophoblastic disease. * **C. Estriol (uE3):** Unconjugated estriol is typically decreased in Down syndrome, Edwards syndrome, and conditions like placental sulfatase deficiency. **Clinical Pearls for NEET-PG:** * **Screening vs. Diagnosis:** Maternal Serum AFP (MSAFP) is the screening tool (done at 15–20 weeks); Amniotic fluid AChE is the confirmatory biochemical test. * **Prevention:** 400 mcg/day of Folic Acid for low-risk and 4 mg/day for high-risk (previous child with NTD) starting 1 month pre-conception. * **Lemon & Banana Signs:** Classic ultrasound findings in the fetal skull/cerebellum associated with Spina Bifida.

Question 80: What is the best marker of gestational age in the second trimester?

A. Biparietal diameter (Correct Answer)
B. Head circumference
C. Crown rump length
D. Femur length

Explanation: **Explanation:** The determination of gestational age (GA) via ultrasonography relies on different parameters depending on the trimester. In the **second trimester (13–26 weeks)**, the **Biparietal Diameter (BPD)** is considered the most reliable and classic marker for dating, with an accuracy of ±7–10 days. * **Why BPD is correct:** BPD measures the distance between the outer edge of the proximal skull table and the inner edge of the distal skull table at the level of the thalami and cavum septum pellucidum. During the second trimester, fetal growth is rapid and linear, making BPD highly reproducible and accurate for dating before biological growth variations (like IUGR or macrosomia) become significant in the third trimester. **Analysis of Incorrect Options:** * **Crown-Rump Length (CRL):** This is the **most accurate** overall method for pregnancy dating, but only in the **first trimester** (up to 13 weeks 6 days). After this, the fetus begins to curl/flex, making linear measurement inaccurate. * **Head Circumference (HC):** While HC is more reliable than BPD if the head shape is anomalous (e.g., dolichocephaly or brachycephaly), BPD remains the standard "best marker" in a normally shaped head during the second trimester. * **Femur Length (FL):** This is a useful parameter but is generally slightly less accurate than head measurements for dating. It is most valuable when head measurements are difficult to obtain. **High-Yield Clinical Pearls for NEET-PG:** * **Best overall dating:** CRL in the 1st Trimester (accuracy ±3–5 days). * **Best 2nd Trimester dating:** BPD (accuracy ±7–10 days). * **Best 3rd Trimester dating:** Femur Length (though accuracy drops significantly to ±21 days). * **Transcerebellar Diameter:** A unique marker that remains stable even in cases of Intrauterine Growth Restriction (IUGR).

Practice by Chapter

Preconception Counseling

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Pregnancy Diagnosis and Dating

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Routine Antenatal Assessments

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Maternal Physiological Changes

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Nutrition in Pregnancy

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Screening Tests in Pregnancy

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Fetal Growth Assessment

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High-Risk Pregnancy Identification

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Antenatal Complications Management

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Psychosocial Aspects of Pregnancy

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