Prenatal Care — MCQs

Prenatal Care Indian Medical PG Practice Questions and MCQs

Question 191: Which of the following is the most sensitive indicator for the detection of iron depletion in pregnancy?

A. Serum iron
B. Serum transferrin
C. Serum erythropoietin
D. Serum ferritin (Correct Answer)

Explanation: **Explanation:** **Serum ferritin** is the most sensitive and specific laboratory indicator for detecting iron depletion in pregnancy. It reflects the total body iron stores. In the early stages of iron deficiency (the "pre-latent" phase), ferritin levels drop before any changes occur in serum iron or hemoglobin levels. A serum ferritin level of **<15–30 µg/L** is diagnostic of depleted iron stores, even in the absence of anemia. **Analysis of Incorrect Options:** * **Serum iron (A):** This measures the iron currently bound to transferrin. It is a poor indicator because it fluctuates significantly based on recent dietary intake and shows diurnal variation. * **Serum transferrin (B):** Transferrin (measured via Total Iron Binding Capacity - TIBC) increases during iron deficiency. However, it is less sensitive than ferritin because it only rises significantly once iron stores are already exhausted. * **Serum erythropoietin (C):** This hormone increases in response to hypoxia or significant anemia to stimulate RBC production. It is not a specific or sensitive marker for iron stores. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Bone marrow aspiration (Prussian blue staining) is the gold standard for assessing iron stores, but **Serum Ferritin** is the investigation of choice (most sensitive non-invasive test). * **The "Rule of 3" in Pregnancy:** * Hb < 11 g/dL (1st & 3rd Trimester) or < 10.5 g/dL (2nd Trimester) defines anemia. * Daily elemental iron requirement: **4–6 mg**. * Prophylactic dose (IFA): **60 mg** elemental iron + **500 µg** folic acid for 180 days. * **Note:** Ferritin is an acute-phase reactant; its levels may be falsely elevated in the presence of systemic infection or inflammation.

Question 192: A pregnant female infected with rubella virus at 22 weeks of gestation. What is the recommended management?

A. Rubella vaccination
B. Rubella immunoglobulin intramuscularly
C. Antiviral drug
D. Reassurance (Correct Answer)

Explanation: 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.

Question 193: 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?

A. 4
B. 40
C. 400
D. 4000 (Correct Answer)

Explanation: **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 194: What is the recommended treatment for pregnant women with syphilis?

A. Tetracycline
B. Oral penicillin
C. Parenteral penicillin (Correct Answer)
D. Aminoglycosides

Explanation: **Explanation:** The treatment of choice for syphilis in pregnancy is **Parenteral Penicillin G**. This is the only documented effective therapy that treats both the mother and the fetus (as it crosses the placenta) and prevents congenital syphilis. * **Why Parenteral Penicillin is correct:** Penicillin G is bactericidal against *Treponema pallidum*. For primary, secondary, or early latent syphilis, a single IM dose of **Benzathine Penicillin G (2.4 million units)** is recommended. For late latent syphilis or syphilis of unknown duration, three doses at weekly intervals are required. * **Why the others are incorrect:** * **Tetracycline/Doxycycline:** These are contraindicated in pregnancy as they are teratogenic (causing dental discoloration and affecting fetal bone growth). * **Oral Penicillin:** Oral formulations do not achieve the sustained, therapeutic serum levels necessary to reliably cure the infection or reach the fetus. * **Aminoglycosides:** These are ineffective against *T. pallidum* and carry risks of fetal ototoxicity. **High-Yield Clinical Pearls for NEET-PG:** 1. **Penicillin Allergy:** If a pregnant woman is allergic to penicillin, she **must** undergo **desensitization** followed by treatment with Penicillin G. No other alternative (like Erythromycin or Azithromycin) is considered reliable for preventing congenital syphilis. 2. **Jarisch-Herxheimer Reaction:** This is an acute febrile reaction occurring within 24 hours of starting treatment. In pregnancy, it can trigger preterm labor or fetal distress; however, treatment should not be delayed. 3. **Screening:** Universal screening is recommended at the first prenatal visit using non-treponemal tests (VDRL/RPR).

Question 195: What is the best investigation to diagnose fetal age?

A. Serial ultrasound (Correct Answer)
B. Amniocentesis
C. Fundal height measurement
D. X-ray

Explanation: **Explanation:** The determination of gestational age (GA) is a cornerstone of prenatal care. **Serial ultrasound (USG)** is the gold standard for diagnosing fetal age because it provides objective, reproducible measurements of fetal biometry. While a single early scan (especially in the first trimester) is the most accurate for dating, serial scans allow clinicians to track growth velocity and refine the estimated date of delivery (EDD) by correlating multiple parameters like Crown-Rump Length (CRL), Biparietal Diameter (BPD), and Femur Length (FL) over time. **Analysis of Incorrect Options:** * **Amniocentesis:** This is an invasive procedure used primarily for genetic testing (karyotyping) or assessing fetal lung maturity (L/S ratio). It does not provide information regarding fetal age. * **Fundal height measurement:** This is a clinical screening tool (McDonald’s rule). It is highly subjective and prone to error due to factors like maternal obesity, multiple gestations, polyhydramnios, or fetal growth restriction (IUGR). * **X-ray:** Historically used to visualize ossification centers (e.g., distal femoral epiphysis at 36 weeks), it is now obsolete for dating due to radiation risks and the superior precision of ultrasound. **High-Yield Clinical Pearls for NEET-PG:** * **Most accurate USG parameter:** Crown-Rump Length (CRL) measured between 7–12 weeks (error margin ± 3–5 days). * **Second trimester:** Biparietal Diameter (BPD) is the most reliable parameter (error margin ± 7–10 days). * **Naegele’s Rule:** EDD = LMP + 9 months + 7 days (only reliable if the patient has a regular 28-day cycle). * **Biological variability:** As pregnancy progresses, the accuracy of USG for dating decreases; third-trimester scans have an error margin of ± 3 weeks.

Question 196: Hypospadias in a baby is caused by maternal use of which of the following drugs?

A. Diethyl stilbesterol
B. Tolbutamide
C. Clomiphene (Correct Answer)
D. Clobazam

Explanation: **Explanation:** The correct answer is **Clomiphene (Option C)**. **Medical Concept:** Clomiphene citrate is a Selective Estrogen Receptor Modulator (SERM) commonly used for ovulation induction. While generally considered safe when used as directed, its use has been epidemiologically linked to an increased risk of **hypospadias** in male offspring. The underlying mechanism is thought to involve the drug's long half-life; residual clomiphene may interfere with the estrogen-androgen balance during the critical period of urethral fold fusion (usually between 8–14 weeks of gestation), leading to the displacement of the urethral meatus. **Analysis of Incorrect Options:** * **A. Diethylstilbestrol (DES):** Historically associated with **Clear Cell Adenocarcinoma of the vagina** and structural uterine anomalies (T-shaped uterus) in female offspring, and epididymal cysts or cryptorchidism in males, but not primarily hypospadias. * **B. Tolbutamide:** A first-generation sulfonylurea. While poorly controlled maternal diabetes is teratogenic, tolbutamide specifically is more associated with neonatal hypoglycemia rather than structural penile defects. * **D. Clobazam:** A benzodiazepine. Maternal use of benzodiazepines is more traditionally linked to "Floppy Infant Syndrome" or, controversially, orofacial clefts, but not hypospadias. **High-Yield NEET-PG Pearls:** * **Hypospadias** is the most common congenital anomaly of the penis. * **Clomiphene** is the first-line treatment for WHO Group II ovulation disorders (e.g., PCOS). * Other drugs linked to hypospadias include **Finasteride** (due to 5-alpha reductase inhibition) and maternal exposure to **Valproate**. * **Surgical correction** for hypospadias is ideally performed between **6 to 12 months** of age. Circumcision should be avoided as the prepuce is needed for repair.

Question 197: What is the best method for diagnosing Trisomy-21 during the second trimester of pregnancy?

A. Triple marker estimation
B. Nuchal skin fold thickness measurement
C. Chorionic villus sampling
D. Amniocentesis (Correct Answer)

Explanation: ### Explanation The diagnosis of chromosomal abnormalities like Trisomy 21 (Down Syndrome) is categorized into **Screening tests** (which calculate risk) and **Diagnostic tests** (which provide a definitive karyotype). **Why Amniocentesis is the Correct Answer:** Amniocentesis is the **gold standard diagnostic test** in the second trimester (typically performed between 15–20 weeks). It involves ultrasound-guided aspiration of amniotic fluid containing fetal desquamated cells. these cells are cultured for **karyotyping** or analyzed via **FISH/QF-PCR**, providing a definitive diagnosis with >99% accuracy. **Analysis of Incorrect Options:** * **A. Triple marker estimation:** This is a **screening test** performed between 15–20 weeks (measuring AFP, hCG, and uE3). It only provides a probability of risk, not a diagnosis. * **B. Nuchal skin fold thickness:** This is a second-trimester **soft marker** on ultrasound (significant if ≥6 mm). While it increases the suspicion of Down Syndrome, it is not diagnostic. (Note: Do not confuse this with *Nuchal Translucency*, which is measured in the first trimester). * **C. Chorionic villus sampling (CVS):** While CVS is a definitive diagnostic test, it is performed in the **first trimester** (10–13 weeks). It is generally avoided in the second trimester due to technical difficulty and the availability of amniocentesis. **High-Yield Clinical Pearls for NEET-PG:** * **Best Screening Test (Overall):** Combined Test (NT scan + PAPP-A + hCG) in the first trimester. * **Best Diagnostic Test (First Trimester):** Chorionic Villus Sampling (CVS). * **Most Common Ultrasound Marker (Second Trimester):** Increased Nuchal Fold thickness. * **Amniocentesis Risk:** The procedure-related risk of miscarriage is approximately 0.5% (1 in 200). * **Quadruple Marker:** Includes the Triple marker components plus **Inhibin-A** (increased in Trisomy 21).

Question 198: A 30-year-old woman presents with amenorrhoea of 6 weeks duration and a lump in the right iliac fossa. What is the investigation of choice?

A. Ultrasound abdomen (Correct Answer)
B. Laparoscopy
C. Shielded CT scan
D. X-ray

Explanation: **Explanation:** The clinical presentation of **amenorrhoea (6 weeks)** combined with a **lump in the right iliac fossa** in a woman of reproductive age is highly suspicious for an **Ectopic Pregnancy** or a **Corpus Luteum cyst**. **Why Ultrasound (USG) is the Investigation of Choice:** Ultrasound (specifically Transvaginal Sonography/TVS) is the gold standard first-line investigation for early pregnancy complications. It is non-invasive, cost-effective, and lacks ionizing radiation, making it safe for the fetus. It can accurately confirm intrauterine pregnancy, identify an adnexal mass (like a tubal pregnancy), and detect free fluid in the Pouch of Douglas (suggestive of rupture). **Analysis of Incorrect Options:** * **Laparoscopy (Option B):** While it is the **Gold Standard for diagnosis** and treatment of ectopic pregnancy, it is an invasive surgical procedure. It is reserved for cases where USG is inconclusive or the patient is hemodynamically unstable. * **Shielded CT scan (Option C):** CT involves high doses of ionizing radiation. Even with shielding, it is contraindicated in early pregnancy due to the risk of teratogenicity and is less sensitive than USG for pelvic structures. * **X-ray (Option D):** X-rays have no role in diagnosing early pregnancy or soft tissue pelvic masses and pose a radiation risk. **High-Yield Clinical Pearls for NEET-PG:** * **Discriminatory Zone:** The level of serum β-hCG at which an intrauterine gestational sac should be visible on USG (TVS: 1500–2000 mIU/ml; TAS: 6500 mIU/ml). * **Classic Triad of Ectopic Pregnancy:** Amenorrhoea, abdominal pain, and vaginal bleeding (present in only 50% of cases). * **Most common site of Ectopic Pregnancy:** Ampulla of the Fallopian tube.

Question 199: What is the earliest sign of pregnancy visualized on transvaginal sonography (TVS)?

A. Gestational sac (Correct Answer)
B. Fetal pole
C. Yolk sac
D. Fetal heart sounds

Explanation: The earliest sonographic evidence of pregnancy is the **Gestational Sac**. In a normal intrauterine pregnancy, it can be visualized via Transvaginal Sonography (TVS) as early as **4.5 to 5 weeks** of gestation (when the Mean Sac Diameter is approximately 2–3 mm). It appears as a small, eccentric fluid collection within the endometrium, often surrounded by the "double decidual sign." ### Why the other options are incorrect: * **Yolk Sac:** This is the first structure to appear *inside* the gestational sac. It is typically visible via TVS at **5 to 5.5 weeks**. Its presence confirms an intrauterine pregnancy and rules out a pseudogestational sac. * **Fetal Pole:** The embryo (fetal pole) becomes visible adjacent to the yolk sac at approximately **6 weeks** via TVS. * **Fetal Heart Sounds:** Cardiac activity is the first sign of a living embryo and is usually detected when the fetal pole reaches 5 mm in length, typically around **6 to 6.5 weeks** via TVS. ### High-Yield Clinical Pearls for NEET-PG: * **Discriminatory Zone:** This is the level of serum β-hCG at which a gestational sac should definitely be visible. For TVS, this is **1,500–2,000 mIU/mL** (for TAS, it is 6,500 mIU/mL). Failure to see a sac above these levels suggests ectopic pregnancy or miscarriage. * **Order of Appearance (TVS):** Gestational Sac (5 wks) → Yolk Sac (5.5 wks) → Fetal Pole/Heartbeat (6 wks). * **Rule of Thumb:** Transvaginal sonography (TVS) is generally **1 week ahead** of Transabdominal sonography (TAS) in detecting early pregnancy landmarks.

Question 200: Nuchal translucency is best measured at which gestational age?

A. 8-10 weeks
B. 11-13 weeks (Correct Answer)
C. 15-17 weeks
D. 18-20 weeks

Explanation: **Explanation:** Nuchal Translucency (NT) refers to the subcutaneous collection of fluid behind the fetal neck. It is a critical screening marker for chromosomal abnormalities (especially Trisomy 21) and structural defects like congenital heart disease. **Why 11–13 weeks is correct:** The optimal window for NT measurement is **11 weeks to 13 weeks and 6 days** (specifically when the Crown-Rump Length is between **45 mm and 84 mm**). * **Physiological Basis:** Before 11 weeks, the fetus is too small for technically accurate measurement. After 14 weeks, the fetal lymphatic system typically develops enough to drain the excess fluid, causing the translucency to disappear or evolve into a nuchal fold, rendering the test unreliable for first-trimester screening. **Analysis of Incorrect Options:** * **A (8–10 weeks):** The fetus is too small, and the lymphatic system is not yet sufficiently developed to reflect pathological fluid accumulation. * **C & D (15–20 weeks):** This is the window for the **Second Trimester Anomaly Scan**. During this period, we measure **Nuchal Fold Thickness** (abnormal if >6 mm), not Nuchal Translucency. **High-Yield Clinical Pearls for NEET-PG:** * **Cut-off Value:** An NT measurement **>3.5 mm** is generally considered abnormal and associated with Down Syndrome, Turner Syndrome, and Cardiac defects. * **Combined Screening:** NT is often combined with maternal serum markers (**PAPP-A and β-hCG**) to increase the detection rate for Down Syndrome to ~90%. * **Nasal Bone:** Absence of the nasal bone during the 11–13 week scan is another strong soft marker for Trisomy 21.

Practice by Chapter

Preconception Counseling

Practice Questions

Pregnancy Diagnosis and Dating

Practice Questions

Routine Antenatal Assessments

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Maternal Physiological Changes

Practice Questions

Nutrition in Pregnancy

Practice Questions

Screening Tests in Pregnancy

Practice Questions

Fetal Growth Assessment

Practice Questions

High-Risk Pregnancy Identification

Practice Questions

Antenatal Complications Management

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Psychosocial Aspects of Pregnancy

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