Prenatal Care Practice Questions

Q: If a fetus has Down syndrome, what finding will NOT be shown on a quadruple marker screening test?

Low Inhibin A. In the **Quadruple Marker Screening** (performed between 15–20 weeks of gestation), maternal serum levels of four specific substances are measured to assess the risk of chromosomal abnormalities, most notably Trisomy 21 (Down syndrome). ### Why "Low Inhibin A" is the Correct Answer In a pregnancy affected by **Down syndrome**, the level of **Inhibin A is characteristically elevated (High)**, not low. Inhibin A is produced by the placenta, and its elevation is a key marker used to increase the sensitivity of the screening test compared to the triple marker test. ### Analysis of Incorrect Options * **A. High hCG:** This is a **correct** finding in Down syndrome. Along with Inhibin A, hCG levels are typically increased (mnemonic: **HI**gh = **H**CG and **I**nhibin A). * **C. Low AFP:** Alpha-fetoprotein (AFP) is typically **decreased** in Down syndrome. (High AFP is associated with neural tube defects). * **D. Low Estriol (uE3):** Unconjugated estriol is typically **decreased** in Down syndrome due to altered steroidogenesis in the fetal-placental unit. ### NEET-PG High-Yield Pearls * **Mnemonic for Down Syndrome (Quad Test):** Remember **"HI"** is **High** (**H**CG and **I**nhibin A). The others (AFP and Estriol) are **Low**. * **Trisomy 18 (Edwards Syndrome):** All markers (AFP, uE3, and hCG) are typically **decreased**. Inhibin A is usually normal or decreased. * **Timing:** The Quad test is best performed between **15–18 weeks** (though valid up to 22 weeks). * **Combined Test (1st Trimester):** Uses Nuchal Translucency (NT), PAPP-A (Low), and hCG (High). Low PAPP-A is a significant marker for Trisomy 21 in the first trimester.

Q: Which test has the fastest lab processing time for karyotype assessment?

Chorionic villus sampling (CVS). **Explanation:** The speed of karyotype assessment depends on the availability of actively dividing cells. **Chorionic Villus Sampling (CVS)** is the correct answer because it allows for a **"Direct Preparation" (Short-term culture).** Since the cytotrophoblast cells in the chorionic villi are naturally and rapidly dividing, they can be harvested and arrested in metaphase almost immediately. This allows for a preliminary karyotype result within **24 to 48 hours**. **Analysis of Options:** * **Amniocentesis:** This procedure collects fetal desquamated cells (amniocytes) from the amniotic fluid. These cells have a low mitotic index and must be cultured for **10 to 14 days** before enough cells are available for chromosomal analysis. * **Cordocentesis (Percutaneous Umbilical Blood Sampling):** While fetal lymphocytes are used, they still require stimulation with mitogens (like phytohemagglutinin) and culture for approximately **48 to 72 hours**. While fast, CVS direct preparation remains the quickest. * **Doppler flow ultrasound:** This is a functional imaging modality used to assess fetal-placental circulation (e.g., Middle Cerebral Artery or Umbilical Artery flow). It cannot provide a karyotype. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** CVS is performed at **10–13 weeks** (earliest invasive test); Amniocentesis at **15–20 weeks**; Cordocentesis after **18 weeks**. * **Risk:** CVS has a slightly higher risk of fetal loss (~0.5–1%) compared to amniocentesis (~0.5%). * **Limb Reduction Defects:** If CVS is performed before 9–10 weeks, there is a specific risk of oromandibular-limb hypogenesis. * **Confined Placental Mosaicism:** A known limitation of CVS where the placental karyotype does not match the fetal karyotype.

Q: Which of the following biochemical markers is useful in first-trimester screening for Down's syndrome?

PAPP-A. **Explanation:** First-trimester screening for Down syndrome (Trisomy 21) is typically performed between **11 and 13+6 weeks** of gestation. The "Combined Test" includes maternal age, fetal nuchal translucency (NT) via ultrasound, and two biochemical markers: **PAPP-A** (Pregnancy-Associated Plasma Protein-A) and **free β-hCG**. 1. **Why PAPP-A is correct:** In pregnancies affected by Down syndrome, maternal serum levels of **PAPP-A are significantly decreased**, while levels of free β-hCG are increased. PAPP-A is a metalloproteinase produced by the trophoblast; low levels indicate placental dysfunction associated with aneuploidy. **Analysis of Incorrect Options:** * **Inhibin A:** This is a marker used in the **Second-trimester Quadruple Screen** (15–20 weeks). It is elevated in Down syndrome. * **Estradiol:** Specifically, **Unconjugated Estriol (uE3)** is used in the second-trimester Triple or Quadruple screen. It is decreased in Down syndrome. (Note: Estradiol itself is not a standard screening marker). * **Acetylcholinesterase (AChE):** This is a highly specific marker used to confirm **Neural Tube Defects (NTDs)**. It is measured in amniotic fluid following an elevated maternal serum alpha-fetoprotein (MSAFP) result. **High-Yield Clinical Pearls for NEET-PG:** * **The "H-i" Rule:** In Down syndrome, only **H**CG and **I**nhibin-A are **High** (elevated) during second-trimester screening; all other markers (AFP, uE3, PAPP-A) are low. * **Best Time for NT:** 11 weeks to 13 weeks 6 days (CRL 45–84 mm). * **Integrated Screen:** Combines first-trimester (NT + PAPP-A) and second-trimester (Quadruple screen) results for the highest detection rate (~95%).

Q: Chorionic villus sampling is done for all the following indications EXCEPT?

Gastroschisis. **Explanation:** The correct answer is **Gastroschisis**. **1. Why Gastroschisis is the correct answer:** Chorionic Villus Sampling (CVS) is a technique used to obtain fetal tissue for **genetic, metabolic, and DNA analysis**. Gastroschisis is a structural ventral wall defect, not a chromosomal or genetic disorder. Structural anomalies like gastroschisis or neural tube defects (NTDs) are diagnosed via **maternal serum alpha-fetoprotein (MSAFP) screening** and confirmed by **detailed ultrasonography**. CVS cannot detect structural defects because it analyzes the chromosomal makeup, not the physical anatomy or protein markers in the amniotic fluid. **2. Analysis of incorrect options:** * **Options A & B (Down Syndrome / Trisomy 21):** These are chromosomal aneuploidies. CVS allows for a full karyotype or FISH (Fluorescence In Situ Hybridization) to definitively diagnose Trisomy 21. * **Option C (Phenylketonuria):** This is an autosomal recessive metabolic disorder. Since the genetic mutation is present in every cell of the conceptus, DNA analysis of the chorionic villi can identify the specific metabolic mutation. **3. High-Yield Clinical Pearls for NEET-PG:** * **Timing:** CVS is typically performed between **10–13 weeks** of gestation (First Trimester). * **Advantage:** It provides earlier results compared to amniocentesis (15–20 weeks). * **Limitation:** It cannot detect Neural Tube Defects (NTDs). * **Complications:** The most specific risk associated with CVS performed before 9 weeks is **Limb Reduction Defects**. * **Confirmatory Test:** CVS is a diagnostic test, whereas the Combined Test (nuchal translucency + PAPP-A + hCG) is only a screening test.

Q: A 25-year-old lady presents with a pregnancy of 6 weeks. Which of the following is NOT a sign of early pregnancy?

Cullen's sign. **Explanation:** The correct answer is **Cullen’s sign**. This question tests the ability to differentiate between physiological signs of early pregnancy and signs of pathological conditions like ruptured ectopic pregnancy. **1. Why Cullen’s Sign is the Correct Answer:** Cullen’s sign is defined as bluish discoloration or ecchymosis around the umbilicus. It is caused by the tracking of hemoperitoneum (blood in the peritoneal cavity) through the falciform ligament. While it can be seen in a **ruptured ectopic pregnancy**, it is not a physiological sign of a normal early pregnancy. It is also classically associated with acute hemorrhagic pancreatitis. **2. Analysis of Incorrect Options (Physiological Signs):** * **Goodell’s Sign (6–8 weeks):** Softening of the cervix due to increased vascularity and hypertrophy of the cervical glands. * **Hegar’s Sign (6–10 weeks):** Softening of the lower uterine segment (isthmus). On bimanual examination, the upper body of the uterus and the cervix seem like two separate regions because the isthmus is so soft it can be compressed almost paper-thin. * **Palmer’s Sign (4–8 weeks):** Regular, rhythmic, painless uterine contractions felt during a bimanual examination. **High-Yield Clinical Pearls for NEET-PG:** * **Chadwick’s Sign (6–8 weeks):** Bluish discoloration of the cervix, vagina, and labia due to venous congestion (also called Jacquemier’s sign). * **Osiander’s Sign (8 weeks):** Increased pulsations felt in the lateral vaginal fornices due to increased vascularity. * **Piskacek’s Sign:** Asymmetrical enlargement of the uterus if implantation occurs near one of the cornua. * **Ladins Sign (6 weeks):** Softening of the anterior midline of the uterus at the junction with the cervix.

Q: A pregnant woman presents for prenatal care. Her past medical history is significant for a severe illness 3 years ago characterized by fatigue, nausea, anorexia, vomiting, jaundice, joint pains, and generalized skin lesions that slowly disappeared. She has felt well recently. Which lab test should be ordered to investigate the patient's past illness?

Hepatitis B surface antigen (HBsAg). **Explanation:** The patient’s history of jaundice, fatigue, joint pains, and skin lesions (likely Gianotti-Crosti syndrome or urticaria associated with the prodromal phase) strongly suggests a past episode of **Acute Hepatitis B**. In the context of prenatal care, the primary concern is the risk of **Vertical Transmission** (mother-to-child). **1. Why HBsAg is the correct answer:** Hepatitis B surface antigen (HBsAg) is the first serological marker to appear in an infection and the standard screening test in pregnancy. If the patient failed to clear the virus after her illness 3 years ago, she would be a **chronic carrier** (defined by HBsAg persistence for >6 months). Identifying HBsAg-positive status is crucial because it dictates the need for neonatal immunoprophylaxis (HBV vaccine + HBIG) to prevent chronic infection in the newborn. **2. Why the other options are incorrect:** * **IgG CMV antibody:** While CMV is a TORCH infection, the patient’s specific history of jaundice and joint pain is more characteristic of viral hepatitis than CMV. * **IgM antibody to HBsAg:** This is not a standard clinical marker. We measure antibodies *against* the surface antigen (Anti-HBs) to check for immunity, not IgM. * **IgM antibody to HBcAg:** This marker is a sign of **acute** infection or a flare-up. Since her illness occurred 3 years ago and she is currently asymptomatic, this would likely be negative. **Clinical Pearls for NEET-PG:** * **Vertical Transmission Risk:** If a mother is HBsAg positive and **HBeAg positive**, the risk of transmission to the neonate is **90%**. If she is HBeAg negative, the risk drops to about 10-20%. * **Management:** Infants born to HBsAg+ mothers must receive the **HBV vaccine and Hepatitis B Immunoglobulin (HBIG)** within 12 hours of birth. * **Universal Screening:** All pregnant women are screened for HBsAg at the first prenatal visit, regardless of prior testing or vaccination status.

Q: What is the total iron requirement during pregnancy?

1000 mg. **Explanation:** The total iron requirement during a normal singleton pregnancy is approximately **1000 mg**. This requirement is driven by the physiological demands of both the mother and the developing fetus. The distribution of this 1000 mg is as follows: * **Fetus and Placenta:** ~300 mg * **Expansion of Maternal Red Cell Mass:** ~450 mg (to support increased oxygen delivery) * **Obligatory Losses (Skin, Gut, Urine):** ~200 mg * **Blood Loss during Delivery:** ~50 mg (net loss) **Analysis of Options:** * **Option A (1000 mg):** Correct. This represents the cumulative need across all three trimesters. * **Option B (35 mg):** Incorrect. This is roughly the daily iron requirement during the third trimester (approx. 6–7 mg/day), not the total pregnancy requirement. * **Option C (500 mg):** Incorrect. This only covers the maternal red cell expansion but ignores fetal needs and obligatory losses. * **Option D (800 mg):** Incorrect. While some older texts cited 800 mg, modern obstetric guidelines (Williams Obstetrics) standardize the total requirement at 1000 mg. **Clinical Pearls for NEET-PG:** * **Iron Absorption:** Iron absorption increases significantly as pregnancy progresses (minimal in the 1st trimester, peaking in the 3rd). * **Prophylactic Dose:** The Government of India (IFA program) recommends **60 mg elemental iron + 500 mcg folic acid** daily for 180 days starting from the second trimester. * **Therapeutic Dose:** For diagnosed anemia (Hb <11 g/dL), the dose is doubled (120 mg elemental iron daily). * **Net Gain:** Despite the 1000 mg requirement, the "net loss" to the mother is only about 500–600 mg because the iron used for red cell expansion is returned to maternal stores after delivery.

Q: What is the percentage increase seen in plasma volume during pregnancy?

40-50%. **Explanation:** The correct answer is **40-50%**. During pregnancy, the maternal body undergoes significant cardiovascular adaptations to meet the metabolic demands of the fetus and protect the mother against blood loss during delivery. **Why 40-50% is correct:** Plasma volume begins to increase as early as the 6th week of gestation, reaching its peak around **32–34 weeks**. This expansion is driven by the activation of the Renin-Angiotensin-Aldosterone System (RAAS), leading to sodium and water retention. While plasma volume increases by approximately **40–50%** (roughly 1.25 liters), the Red Blood Cell (RBC) mass only increases by about **20–30%**. This disproportionate rise leads to **physiological anemia of pregnancy** due to hemodilution. **Why other options are incorrect:** * **A & B (10-30%):** These values are too low for plasma volume but roughly correspond to the increase in **RBC mass** (20-30%). * **C (30-40%):** While closer, this underestimates the total expansion seen in a singleton pregnancy, which typically reaches the 45-50% mark by the third trimester. **High-Yield Clinical Pearls for NEET-PG:** 1. **Cardiac Output:** Increases by **30–50%**, peaking at 20–24 weeks. 2. **Stroke Volume:** Increases by 25–30%. 3. **Multiple Gestation:** In twin pregnancies, the plasma volume increase is even higher (up to 70%). 4. **Uterine Blood Flow:** Increases from 50 mL/min (pre-pregnancy) to approximately **500–750 mL/min** at term. 5. **Blood Pressure:** Diastolic BP decreases in the first and second trimesters (nadir at 24 weeks) due to decreased systemic vascular resistance (SVR) mediated by progesterone and nitric oxide.

Question 1

A 23-year-old female presents with a missed menstrual period of two cycles and a positive urine pregnancy test. Ultrasound confirms a 12-week gestation. She is concerned because she received the Measles Mumps Rubella (MMR) vaccine four months prior to conception, having been advised to wait three months before conceiving. The pregnancy is desired. What is the most appropriate next step?

Accepted Answer

The risk associated with the MMR vaccine is minimal and not a sufficient reason to terminate the pregnancy.

Answer

The risk associated with the MMR vaccine is nil, and termination is inappropriate.

Answer

The risk associated with the MMR vaccine is high, and termination should be strongly considered.

Answer

The risk associated with the MMR vaccine is high, and termination is mandated.

Question 2

If a fetus has Down syndrome, what finding will NOT be shown on a quadruple marker screening test?

Accepted Answer

Low Inhibin A

Answer

High hCG

Answer

Low AFP

Answer

Low Estriol

Question 3

Which test has the fastest lab processing time for karyotype assessment?

Accepted Answer

Chorionic villus sampling (CVS)

Answer

Amniocentesis

Answer

Cordocentesis

Answer

Doppler flow ultrasound

Question 4

Which of the following biochemical markers is useful in first-trimester screening for Down's syndrome?

Accepted Answer

PAPP-A

Answer

Inhibin

Answer

Estradiol

Answer

Acetylcholinesterase

Question 5

Chorionic villus sampling is done for all the following indications EXCEPT?

Accepted Answer

Gastroschisis

Answer

Down syndrome

Answer

Trisomy 21

Answer

Phenylketonuria

Question 6

A 25-year-old lady presents with a pregnancy of 6 weeks. Which of the following is NOT a sign of early pregnancy?

Accepted Answer

Cullen's sign

Answer

Goodell's sign

Answer

Hegar's sign

Answer

Palmer's sign

Question 7

A pregnant woman presents for prenatal care. Her past medical history is significant for a severe illness 3 years ago characterized by fatigue, nausea, anorexia, vomiting, jaundice, joint pains, and generalized skin lesions that slowly disappeared. She has felt well recently. Which lab test should be ordered to investigate the patient's past illness?

Accepted Answer

Hepatitis B surface antigen (HBsAg)

Answer

IgG cytomegalovirus (CMV) antibody levels

Answer

IgM antibody to HBsAg

Answer

IgM antibody to hepatitis B core antigen

Question 8

What is the total iron requirement during pregnancy?

Accepted Answer

1000 mg

Answer

35 mg

Answer

500 mg

Answer

800 mg

Question 9

What does Chadwick sign indicate?

Accepted Answer

Bluish discoloration or dusky hue of the vestibule and anterior vaginal wall

Answer

Pulsations felt through lateral fornices

Answer

Softening of the cervix

Answer

All of the above

Question 10

What is the percentage increase seen in plasma volume during pregnancy?

Accepted Answer

40-50%

Answer

10-20%

Answer

20-30%

Answer

30-40%

Prenatal Care — MCQs

Prenatal Care — MCQs

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