Prenatal Care Practice Questions

Q: Genetic disorders are diagnosed at 11 weeks of pregnancy by?

Chorionic villous biopsy. **Explanation:** The correct answer is **Chorionic Villous Biopsy (CVS)**. **1. Why Chorionic Villous Biopsy (CVS) is correct:** CVS is the preferred invasive prenatal diagnostic test in the **first trimester**, typically performed between **10 and 13 weeks** of gestation. It involves taking a sample of the chorionic villi (placental tissue), which shares the same genetic makeup as the fetus. Because it can be performed earlier than other invasive tests, it allows for earlier diagnosis of chromosomal abnormalities (like Down Syndrome) or single-gene disorders, providing parents with earlier options for pregnancy management. **2. Why the other options are incorrect:** * **Amniocentesis:** This involves sampling amniotic fluid. It is traditionally performed in the **second trimester**, between **15 and 20 weeks**. Performing it before 14 weeks (early amniocentesis) is associated with higher risks of fetal loss and clubfoot (talipes equinovarus). * **Endometrial biopsy:** This is a gynecological procedure used to sample the uterine lining to investigate infertility or abnormal uterine bleeding; it is **contraindicated** in a known pregnancy. * **Placentography:** This is an obsolete radiological technique (X-ray) previously used to visualize the placenta. It is not used for genetic diagnosis. **High-Yield Clinical Pearls for NEET-PG:** * **Timing is Key:** CVS (10–13 weeks) vs. Amniocentesis (15–20 weeks). * **Risk of Limb Reduction:** If CVS is performed **before 9 weeks**, there is an increased risk of limb reduction defects. * **Mosaicism:** CVS has a 1–2% risk of "Confined Placental Mosaicism," where the placenta's genetic makeup differs from the fetus, sometimes requiring follow-up amniocentesis for confirmation. * **Procedure-related Loss:** The risk of miscarriage for both CVS and amniocentesis is now considered very low (approx. 0.1% to 0.5%) in experienced centers.

Q: What gestational sac diameter is suggestive of anembryonic pregnancy if an embryo is not visible?

20 mm. ### Explanation In early pregnancy, transvaginal ultrasonography (TVUS) is the gold standard for assessing viability. An **anembryonic pregnancy** (formerly known as a "blighted ovum") occurs when a gestational sac develops without a detectable embryo. **Why 20 mm is the correct answer:** According to standard obstetric guidelines (including the SRU criteria), a **Mean Sac Diameter (MSD) of ≥25 mm** without a visible embryo is definitive for pregnancy failure. However, in the context of NEET-PG and traditional textbooks like Williams Obstetrics, an **MSD of ≥20 mm** without an embryo (or yolk sac) is considered highly suggestive of anembryonic pregnancy. At this size, the absence of fetal poles indicates that the pregnancy is not progressing normally. **Analysis of Incorrect Options:** * **A (5 mm):** This is the size at which a gestational sac first becomes visible on TVUS (around 4.5–5 weeks). It is too early to expect an embryo. * **B (10 mm):** At this stage, a yolk sac should typically be visible, but the absence of an embryo is still considered normal. * **C (15 mm):** While a yolk sac should definitely be present, the absence of an embryo at 15 mm is suspicious but not yet diagnostic of failure. **High-Yield Clinical Pearls for NEET-PG:** * **Discriminatory Zone:** The hCG level at which a gestational sac should be seen (1500–2000 mIU/ml for TVUS; 6500 mIU/ml for TAS). * **Yolk Sac Rule:** If the MSD is **>8 mm**, a yolk sac should be visible. * **Cardiac Activity:** If the **Crown-Rump Length (CRL) is ≥7 mm**, fetal heart activity must be present; its absence confirms missed abortion. * **Growth Rate:** A normal gestational sac grows at approximately **1 mm per day**.

Q: Which of the following is the investigation of choice in a pregnant lady at 18 weeks of gestation with a past history of delivering a baby with Down's syndrome?

Amniocentesis. **Explanation:** The core concept here is the distinction between **screening** and **diagnostic** tests. A woman with a previous history of a child with Down’s syndrome is at a significantly higher risk for recurrence. In such high-risk scenarios, a definitive diagnosis is required rather than a probability-based screening. **Why Amniocentesis is correct:** Amniocentesis is the **investigation of choice (diagnostic test)** for chromosomal analysis at 18 weeks. It involves aspirating amniotic fluid to perform fetal karyotyping. It is typically performed between **15–20 weeks** of gestation. Since the patient is at 18 weeks, this is the most appropriate and safest invasive procedure available to confirm or rule out trisomy 21. **Why other options are incorrect:** * **Triple Screen Test:** This is a screening test (measuring AFP, hCG, and uE3). While it assesses risk, it does not provide a definitive diagnosis. In a patient with a known high-risk history, we bypass screening and proceed directly to diagnostic testing. * **Chorionic Villous Biopsy (CVS):** While diagnostic, CVS is ideally performed between **10–13 weeks**. At 18 weeks, the placenta is more developed, and the risk-to-benefit ratio favors amniocentesis. * **Ultrasonography:** USG can identify "soft markers" (like nuchal fold thickness), but it is not a definitive diagnostic tool for Down’s syndrome. **High-Yield Pearls for NEET-PG:** * **Gold Standard for Karyotyping:** Amniocentesis. * **Timing:** CVS (10–13 weeks); Amniocentesis (15–20 weeks); Cordocentesis (>20 weeks). * **Most common chromosomal abnormality** associated with increased maternal age/previous history: Trisomy 21 (Down’s Syndrome). * **Risk of miscarriage:** Amniocentesis carries a lower risk (~0.5%) compared to CVS (~1%).

Q: Chorionic villous sampling is useful in the diagnosis of all the following conditions except?

Spina bifida. **Explanation:** The correct answer is **Spina bifida**. **1. Why Spina bifida is the correct answer:** Chorionic Villous Sampling (CVS) involves obtaining a sample of placental tissue (chorionic villi) to analyze the fetal genome. It is used to detect **genetic, chromosomal, and metabolic disorders**. Spina bifida is a **Neural Tube Defect (NTD)**, which is a structural malformation, not a primary genetic sequence error. The diagnosis of NTDs relies on identifying elevated levels of **Alpha-fetoprotein (AFP)** in maternal serum or amniotic fluid, and visualization via **Targeted Ultrasonography**. Since CVS does not measure AFP levels, it cannot be used to diagnose Spina bifida. **2. Analysis of incorrect options:** * **Tay-Sachs disease:** This is an autosomal recessive lysosomal storage disorder. It can be diagnosed via CVS through DNA analysis or enzyme assay of the villi. * **Thalassemia:** As a single-gene disorder (hemoglobinopathy), it is diagnosed using DNA amplification (PCR) from the fetal cells obtained during CVS. * **Down syndrome:** This is a chromosomal aneuploidy (Trisomy 21). CVS allows for a full fetal karyotype or FISH analysis, making it a definitive diagnostic tool for chromosomal abnormalities. **3. NEET-PG High-Yield Pearls:** * **Timing:** CVS is typically performed between **10–13 weeks** of gestation (earlier than amniocentesis). * **Risk:** Performing CVS before 9 weeks is associated with **Limb Reduction Defects**. * **Advantage:** It provides earlier results compared to amniocentesis, allowing for safer first-trimester termination if necessary. * **Limitation:** It cannot detect NTDs and carries a small risk of **Confined Placental Mosaicism**, which may require follow-up amniocentesis.

Q: Which of the following is the most specific marker for Neural Tube Defects?

Acetylcholinesterase. **Explanation:** The correct answer is **Acetylcholinesterase (AChE)**. **1. Why Acetylcholinesterase is the Correct Answer:** While Alpha-fetoprotein (AFP) is the most common *screening* tool, **AChE is the most specific marker** for confirming Neural Tube Defects (NTDs). In a fetus with an open NTD (like anencephaly or open spina bifida), the fetal cerebrospinal fluid (CSF) leaks directly into the amniotic fluid. Since AChE is an enzyme found in high concentrations within the fetal central nervous system, its presence in the amniotic fluid (detected via amniocentesis and gel electrophoresis) is a definitive indicator of exposed neural tissue. **2. Analysis of Incorrect Options:** * **Alpha-fetoprotein (AFP):** This is highly sensitive but lacks specificity. Elevated levels are seen in NTDs, but also in abdominal wall defects (omphalocele/gastroschisis), multiple gestations, and fetal demise. It is used for screening, not definitive diagnosis. * **Pseudocholinesterase (Butyrylcholinesterase):** This is found in the liver and plasma. It is not a specific marker for neural tissue and does not help in diagnosing NTDs. * **Human Chorionic Gonadotropin (HCG):** This is a marker used in the "Triple" or "Quadruple" screen primarily to screen for chromosomal abnormalities like Down Syndrome (where HCG is elevated) or Edwards Syndrome (where HCG is decreased). **3. Clinical Pearls for NEET-PG:** * **Screening Sequence:** Maternal Serum AFP (MSAFP) $\rightarrow$ Ultrasound $\rightarrow$ Amniotic Fluid AFP $\rightarrow$ **Amniotic Fluid AChE (Gold Standard for confirmation).** * **False Positives:** If a sample is contaminated with fetal blood, AFP may be elevated, but the AChE test helps differentiate true NTDs from blood contamination. * **Folic Acid:** Supplementation (400mcg/day for low risk; 4mg/day for high risk) starting 1 month pre-conception reduces NTD incidence by 70%.

Q: A pregnant woman presents with red degeneration of a fibroid. What is the management?

Conservative management. **Explanation:** **Red degeneration** (necrobiosis) is the most common complication of fibroids during pregnancy, typically occurring in the second trimester. It is caused by rapid growth of the fibroid due to high estrogen levels, leading to the tumor outgrowing its blood supply. This results in venous thrombosis, hemorrhage, and infarction within the fibroid. **1. Why Conservative Management is Correct:** Red degeneration is a **self-limiting condition**. The primary goal is to manage the acute symptoms—severe abdominal pain, localized tenderness, low-grade fever, and leukocytosis—until the episode subsides, which usually takes 4–7 days. Management includes **bed rest, intravenous hydration, and analgesics** (NSAIDs or narcotics). Surgery is avoided because the increased pelvic vascularity during pregnancy poses a high risk of life-threatening hemorrhage. **2. Why Other Options are Incorrect:** * **Myomectomy:** Generally contraindicated during pregnancy due to the risk of massive hemorrhage and miscarriage/preterm labor. It is only considered in rare cases of pedunculated fibroid torsion. * **Hysterectomy:** This is an extreme measure and is not indicated for a benign, self-limiting condition like red degeneration. * **Termination of Pregnancy:** Red degeneration does not harm the fetus directly, and symptoms resolve with medical management; therefore, ending the pregnancy is unnecessary. **Clinical Pearls for NEET-PG:** * **Pathology:** Characterized by a "beefy red" appearance and a fishy odor due to the presence of peripheral hemolytic pigment. * **Investigation of Choice:** Ultrasound (shows a cystic/complex mass); however, diagnosis is primarily **clinical**. * **Analgesia:** While NSAIDs are used, they should be avoided after 32 weeks to prevent premature closure of the ductus arteriosus.

Q: A pregnant female infected with rubella virus at 22 weeks of gestation. What is the recommended management?

Reassurance. The correct answer is **D. Reassurance**. ### **Explanation** The risk of Congenital Rubella Syndrome (CRS) is highly dependent on the gestational age at the time of maternal infection. The period of maximum vulnerability is the first trimester (up to 12 weeks), where the risk of fetal infection is approximately 80–90%. After **20 weeks of gestation**, the risk of congenital malformations is virtually **zero**. While the virus can still cross the placenta, it does not cause the classic triad of CRS (cataracts, sensorineural deafness, and cardiac defects) because organogenesis is complete. Therefore, if a woman is infected at 22 weeks, the management is simple reassurance as the pregnancy can proceed normally without fear of teratogenicity. ### **Why Other Options are Incorrect** * **A. Rubella vaccination:** The Rubella vaccine (MMR) is a **live-attenuated vaccine** and is strictly contraindicated during pregnancy due to the theoretical risk of fetal infection. * **B. Rubella immunoglobulin:** Post-exposure prophylaxis with Ig does not prevent fetal infection and is only considered if a non-immune pregnant woman is exposed in early pregnancy and strictly refuses termination. It has no role at 22 weeks. * **C. Antiviral drug:** There is no specific effective antiviral therapy for Rubella infection. ### **NEET-PG High-Yield Pearls** * **Critical Period:** Risk of CRS is highest (<12 weeks: 80-90%), decreases (13–16 weeks: 15%), and becomes negligible after **20 weeks**. * **Gregg’s Triad:** Cataracts, Sensorineural hearing loss (most common), and PDA (Peripheral Pulmonary Artery Stenosis is also common). * **Diagnosis:** Maternal IgM antibodies or a four-fold rise in IgG titers. * **Vaccination Strategy:** If a woman is found to be non-immune during pregnancy, vaccinate in the **immediate postpartum period**. Advise avoiding pregnancy for 1 month (28 days) after vaccination.

Q: A mother with a history of antenatal fetal death due to neural tube defect in her first child presents for preconception counseling. What is the recommended daily dosage of folic acid (in micrograms/day) to be prescribed?

4000. **Explanation:** The primary goal of periconceptional folic acid supplementation is to prevent **Neural Tube Defects (NTDs)**. The dosage is determined by the patient's risk profile: 1. **High-Risk Patients (Correct Answer D):** Women with a **previous history** of a child with an NTD, or if either parent has an NTD, are at high risk for recurrence. The recommended dosage is **4 mg (4000 mcg) per day**. This should ideally start at least 1–3 months before conception and continue through the first trimester. 2. **Low-Risk Patients (Option C):** For women with no prior history of NTDs, the standard prophylactic dose is **0.4 mg (400 mcg) per day**. 3. **Options A and B:** These represent 4 mcg and 40 mcg respectively, which are sub-therapeutic doses and insufficient for preventing congenital malformations. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Folic acid is most effective when started **pre-conceptionally** because the neural tube closes by the **28th day** of gestation (often before a woman knows she is pregnant). * **Other High-Risk Indications for 4 mg:** Mothers with diabetes mellitus (pre-gestational) or those taking anti-epileptic drugs (e.g., Valproate, Carbamazepine) also require the higher 4 mg dose. * **Mechanism:** Folic acid is essential for DNA synthesis and methylation; deficiency leads to failure of the neural folds to fuse. * **Associated Lab Finding:** Elevated **Alpha-Fetoprotein (AFP)** in maternal serum or amniotic fluid is a marker for open NTDs.

Question 1

Genetic disorders are diagnosed at 11 weeks of pregnancy by?

Accepted Answer

Chorionic villous biopsy

Answer

Amniocentesis

Answer

Endometrial biopsy

Answer

Placentography

Question 2

What gestational sac diameter is suggestive of anembryonic pregnancy if an embryo is not visible?

Accepted Answer

20 mm

Answer

5 mm

Answer

10 mm

Answer

15 mm

Question 3

Which of the following is the investigation of choice in a pregnant lady at 18 weeks of gestation with a past history of delivering a baby with Down's syndrome?

Accepted Answer

Amniocentesis

Answer

Triple screen test

Answer

Chorionic villous biopsy

Answer

Ultrasonography

Question 4

A mother at 10 weeks of pregnancy has previously had a baby with an open neural tube defect. Which of the following statements is true?

Accepted Answer

Sodium valproate is associated with open neural tube defects.

Answer

The risk of recurrence is 10%.

Answer

Amniocentesis should be performed.

Answer

Administer multivitamins.

Question 5

Chorionic villous sampling is useful in the diagnosis of all the following conditions except?

Accepted Answer

Spina bifida

Answer

Tay-Sachs disease

Answer

Thalassemia

Answer

Down syndrome

Question 6

Regarding hemodynamic changes in pregnancy, which of the following is NOT true?

Accepted Answer

Hemodynamic changes start taking place after 12 weeks of gestation.

Answer

Venocaval compression begins at about 16 weeks of gestation.

Answer

There is a mid-trimester fall in blood pressure.

Answer

A systolic murmur may occur normally.

Question 7

Which of the following is the most specific marker for Neural Tube Defects?

Accepted Answer

Acetylcholinesterase

Answer

Pseudocholinesterase

Answer

Alpha fetoprotein (AFP)

Answer

Human chorionic Gonadotropin (HCG)

Question 8

A pregnant woman presents with red degeneration of a fibroid. What is the management?

Accepted Answer

Conservative management

Answer

Myomectomy

Answer

Hysterectomy

Answer

Termination of pregnancy

Question 9

A pregnant female infected with rubella virus at 22 weeks of gestation. What is the recommended management?

Accepted Answer

Reassurance

Answer

Rubella vaccination

Answer

Rubella immunoglobulin intramuscularly

Answer

Antiviral drug

Question 10

A mother with a history of antenatal fetal death due to neural tube defect in her first child presents for preconception counseling. What is the recommended daily dosage of folic acid (in micrograms/day) to be prescribed?

Accepted Answer

4000

Answer

4

Answer

40

Answer

400

Prenatal Care — MCQs

Prenatal Care — MCQs

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