Prenatal Care — MCQs

Prenatal Care Indian Medical PG Practice Questions and MCQs

Question 171: What is the recommended timing for a pelvic assessment in a primigravida?

A. 32 weeks
B. 34 weeks
C. 36 weeks
D. 40 weeks (Correct Answer)

Explanation: **Explanation:** The clinical objective of a pelvic assessment (clinical pelvimetry) in a primigravida is to evaluate the adequacy of the bony pelvis and the relationship between the fetal head and the maternal pelvis. **Why 40 weeks is the correct answer:** In a primigravida, the fetal head typically engages between **37 and 38 weeks** of gestation. Performing a pelvic assessment before engagement is often inaccurate because the "best pelvimeter" is the fetal head itself. By **40 weeks**, the head should ideally be engaged; if it is not, a pelvic assessment (including the Müller-Munro Kerr maneuver) is performed to rule out Cephalopelvic Disproportion (CPD). Assessing earlier is premature as the pelvic ligaments have not reached maximum laxity, and the fetal head position is not finalized. **Analysis of Incorrect Options:** * **32 & 34 weeks (Options A & B):** These are too early. The fetal head is high and mobile, and the soft tissues/ligaments are not yet primed by the hormonal changes of late pregnancy. * **36 weeks (Option C):** While some older protocols suggested 36 weeks, modern obstetric practice (and standard NEET-PG textbooks like Dutta) emphasizes that engagement in primigravidae occurs closer to term. Assessing at 36 weeks may lead to a false diagnosis of CPD. **High-Yield Clinical Pearls for NEET-PG:** * **Engagement:** In primigravidae, engagement occurs at 38 weeks. In multigravidae, it often occurs only at the onset of labor. * **Müller-Munro Kerr Maneuver:** This is the clinical method used to assess CPD at term. It is a bimanual procedure where the fetal head is pushed into the pelvis while the internal fingers palpate for descent. * **Diagonal Conjugate:** This is the only diameter of the pelvic inlet that can be measured clinically during a pelvic exam. It is used to estimate the Obstetric Conjugate (Diagonal Conjugate minus 1.5–2 cm).

Question 172: What is the best time for detecting chorionicity in a twin pregnancy on ultrasound?

A. 8-12 weeks
B. 10-14 weeks (Correct Answer)
C. 14-18 weeks
D. 16-24 weeks

Explanation: **Explanation:** Determining chorionicity is the most critical step in managing twin pregnancies, as monochorionic twins carry significantly higher risks (e.g., TTTS). The **best time for detecting chorionicity is 10–14 weeks** (late first trimester). **Why 10–14 weeks is the Correct Answer:** During this window, the ultrasound signs are most distinct. The presence of the **'Lambda' (λ) sign** (or twin-peak sign) indicates a dichorionic pregnancy, where the thick chorion projects into the base of the inter-twin membrane. Conversely, the **'T' sign** indicates a monochorionic pregnancy, where a thin amnion meets the placenta without intervening chorionic tissue. After 14 weeks, the chorion frondosum regresses, and the layers of the inter-twin membrane fuse, making these signs difficult to visualize. **Analysis of Incorrect Options:** * **A (8–12 weeks):** While chorionicity can be seen as early as 7–8 weeks by counting the number of gestational sacs, the definitive membrane signs (Lambda vs. T) are best visualized after 10 weeks when the amniotic sac has expanded. * **C & D (14–24 weeks):** Beyond 14 weeks, the "Lambda sign" often disappears (the "vanishing" Lambda sign) as the chorion laeve regresses. Accuracy drops significantly in the second trimester, often requiring less reliable methods like fetal sex or placental location. **High-Yield Clinical Pearls for NEET-PG:** * **Lambda Sign:** Dichorionic Diamniotic (DCDA). * **T Sign:** Monochorionic Diamniotic (MCDA). * **Gold Standard:** Ultrasound in the first trimester is the gold standard for chorionicity. * **Membrane Thickness:** A membrane >2 mm usually suggests DCDA; <2 mm suggests MCDA. * **Timing of Division:** * 0–72 hours: DCDA * 4–8 days: MCDA * 8–13 days: MCMA (Monochorionic Monoamniotic) * >13 days: Conjoined twins

Question 173: Which of the following is NOT related with fertilization?

A. Sperm crosses corona radiata
B. Implantation occurs after 6 days
C. Zona pellucida facilitation by hyaluronidase
D. Zona reaction attracts the sperms (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Zona reaction attracts the sperms.** **Why Option D is incorrect (and thus the right answer):** The **Zona Reaction** is a defensive mechanism, not an attractive one. Once a single sperm penetrates the oocyte, cortical granules are released into the perivitelline space. This induces a structural change in the zona pellucida (the zona reaction) that makes it impermeable to other spermatozoa. Its primary function is to **prevent polyspermy** (fertilization by more than one sperm), ensuring a diploid zygote. It does not "attract" sperms; rather, it locks them out. **Analysis of other options:** * **Option A:** Capacitated sperms must pass through the **corona radiata** (the outer layer of follicular cells) using hyaluronidase and flagellar movement to reach the zona pellucida. * **Option B:** Fertilization occurs in the ampulla of the fallopian tube. The resulting zygote travels to the uterus, and **implantation** typically begins on the **6th day** after fertilization (the "implantation window"). * **Option C:** The acrosome of the sperm releases enzymes, primarily **hyaluronidase** and acrosin. Hyaluronidase helps disperse the cells of the corona radiata and facilitates the sperm's passage through the zona pellucida. **High-Yield NEET-PG Pearls:** * **Site of Fertilization:** Ampulla of the Fallopian tube (most common). * **Capacitation:** A 7-hour process in the female reproductive tract where the glycoprotein coat is removed from the sperm's plasma membrane. * **Acrosome Reaction:** Triggered when the sperm binds to the **ZP3 receptor** on the zona pellucida. * **Implantation:** Occurs in the **blastocyst stage**. The most common site is the upper posterior wall of the uterus.

Question 174: Which of the following is the most accurate biometric predictor of gestational age?

A. Head Circumference
B. Crown-rump length (Correct Answer)
C. Abdominal circumference
D. Gestational sac mean diameter

Explanation: **Explanation:** The **Crown-Rump Length (CRL)** is the most accurate biometric parameter for dating a pregnancy. It is measured via ultrasound between **7 and 13+6 weeks** of gestation. During this period, fetal growth is rapid and biological variation is minimal, allowing for a dating accuracy of **± 3 to 5 days**. It is the gold standard for establishing the Expected Date of Delivery (EDD). **Analysis of Options:** * **A. Head Circumference (HC):** This is a reliable parameter in the second trimester. However, as pregnancy progresses, biological variation increases, and the accuracy of gestational age estimation decreases (± 7–10 days in the second trimester). * **C. Abdominal Circumference (AC):** This is the most sensitive indicator of **fetal growth and nutrition** (IUGR or Macrosomia) but is the **least accurate** for dating gestational age due to its high variability. * **D. Gestational Sac Mean Diameter:** This is the first sonographic sign of pregnancy (visible at ~4.5–5 weeks), but it is less accurate than CRL because the sac shape can be influenced by bladder filling or uterine contractions. **High-Yield NEET-PG Pearls:** * **First Trimester:** CRL is the best predictor. If CRL is >84 mm, it is no longer used; BPD/HC takes over. * **Second Trimester:** Head Circumference (HC) is generally considered more reliable than BPD as it is not affected by head shape (dolichocephaly/brachycephaly). * **Third Trimester:** Accuracy of ultrasound for dating drops significantly (± 2–3 weeks). * **Rule of Thumb:** The earlier the ultrasound is performed, the more accurate the gestational age estimation.

Question 175: What is the treatment of choice for a pregnant patient with gonorrhea presenting with white discharge?

A. Ceftriaxone single dose intramuscular injection plus Metronidazole for 14 days
B. Ceftriaxone plus azithromycin single dose (Correct Answer)
C. Ceftriaxone plus Doxycycline 100 mg for 7 days plus Metronidazole for 14 days
D. Ceftriaxone single dose intramuscular injection

Explanation: **Explanation:** The treatment of choice for gonorrhea in pregnancy is a combination therapy of **Ceftriaxone (250 mg IM single dose)** and **Azithromycin (1 g orally single dose)**. **1. Why Option B is Correct:** * **Dual Therapy:** Gonorrhea is frequently co-infected with *Chlamydia trachomatis*. To prevent treatment failure and cover both organisms, dual therapy is mandatory. * **Safety in Pregnancy:** Ceftriaxone (a third-generation cephalosporin) and Azithromycin (a macrolide) are both considered safe during pregnancy (Category B). **2. Why Other Options are Incorrect:** * **Option A:** Metronidazole is used for Trichomoniasis or Bacterial Vaginosis, not as a standard adjunct for Gonorrhea/Chlamydia unless specifically indicated. * **Option C:** While Doxycycline is a standard treatment for Chlamydia in non-pregnant adults, it is **contraindicated in pregnancy** due to the risk of fetal dental staining and bone growth inhibition. * **Option D:** Monotherapy with Ceftriaxone is no longer recommended due to the high prevalence of co-infection and the rising threat of antimicrobial resistance. **3. High-Yield Clinical Pearls for NEET-PG:** * **Syndromic Management:** In the WHO/NACO syndromic approach, "Vaginal Discharge" (Green/Yellow) is treated with Kit 2 (Secnidazole + Fluconazole), but confirmed Gonorrhea requires the Ceftriaxone + Azithromycin regimen. * **Neonatal Complication:** Untreated maternal gonorrhea can lead to *Ophthalmia Neonatorum*, which presents within 2–5 days of birth. * **Partner Treatment:** Always treat the sexual partner to prevent reinfection (Ping-pong infection). * **Test of Cure:** In pregnant patients, a test-of-cure is recommended 3–4 weeks after treatment.

Question 176: What is the recommended daily intake of folic acid during the first trimester of a normal pregnancy?

A. 100 micrograms
B. 400 micrograms (Correct Answer)
C. 4 mg
D. 5 mg

Explanation: **Explanation:** The correct answer is **400 micrograms (0.4 mg)**. Folic acid is a critical B-vitamin required for DNA synthesis and amino acid metabolism. During the first trimester, it is essential for the proper closure of the neural tube, which occurs by the 28th day of gestation. **Why Option B is correct:** For a **low-risk (normal) pregnancy**, the WHO and standard obstetric guidelines recommend a daily supplementation of **400 mcg (0.4 mg)** of folic acid. Ideally, this should start at least one month prior to conception (pre-conceptionally) and continue through the first 12 weeks of pregnancy to effectively prevent Neural Tube Defects (NTDs) like spina bifida and anencephaly. **Why the other options are incorrect:** * **Option A (100 mcg):** This dose is insufficient to provide the protective effect required to prevent NTDs. * **Options C & D (4 mg / 5 mg):** These are **high doses**. A 4 mg or 5 mg dose is reserved for **high-risk pregnancies**, including women with a previous history of a child with an NTD, women on anti-epileptic drugs (e.g., Valproate), or those with pre-gestational diabetes or BMI > 35. **NEET-PG High-Yield Pearls:** * **Timing:** Neural tube closure happens between days 22–28 post-conception. Since many women don't know they are pregnant then, pre-conceptional start is vital. * **High-Risk Dose:** 4 mg (or 5 mg in some guidelines) is the standard for secondary prevention (previous NTD). * **Anemia:** In India, under the Anemia Mukt Bharat program, pregnant women are given **60 mg elemental Iron + 500 mcg Folic Acid** daily starting from the second trimester (13 weeks) for 180 days.

Question 177: Genetic disorders are diagnosed at 11 weeks of pregnancy by?

A. Chorionic villous biopsy (Correct Answer)
B. Amniocentesis
C. Endometrial biopsy
D. Placentography

Explanation: **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.

Question 178: What gestational sac diameter is suggestive of anembryonic pregnancy if an embryo is not visible?

A. 5 mm
B. 10 mm
C. 15 mm
D. 20 mm (Correct Answer)

Explanation: ### 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**.

Question 179: 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?

A. Triple screen test
B. Amniocentesis (Correct Answer)
C. Chorionic villous biopsy
D. Ultrasonography

Explanation: **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%).

Question 180: 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?

A. Sodium valproate is associated with open neural tube defects. (Correct Answer)
B. The risk of recurrence is 10%.
C. Amniocentesis should be performed.
D. Administer multivitamins.

Explanation: **Explanation:** **1. Why Option A is Correct:** Sodium Valproate is a known potent teratogen. It interferes with folate metabolism by inhibiting the enzyme dihydrofolate reductase and altering the expression of genes involved in neural tube closure. Epidemiological studies show that valproate exposure in the first trimester carries a 1–2% risk of neural tube defects (NTDs), specifically spina bifida aperta, which is significantly higher than the general population risk. **2. Why Other Options are Incorrect:** * **Option B:** The risk of recurrence after one affected child is approximately **2–3%** (not 10%). The risk increases to about 10% only after two affected siblings. * **Option C:** While amniocentesis can detect alpha-fetoprotein (AFP) and acetylcholinesterase, it is an invasive procedure. The current standard for screening/diagnosis is a **Maternal Serum Alpha-Fetoprotein (MSAFP)** test at 15–20 weeks followed by a high-resolution **Targeted Level II Ultrasound** (Anomaly scan) at 18–20 weeks. * **Option D:** While multivitamins are beneficial, the specific management for a high-risk patient (previous NTD) is **high-dose Folic Acid (5 mg/day)**. Standard multivitamins do not contain enough folic acid to prevent recurrence in high-risk cases. **High-Yield Clinical Pearls for NEET-PG:** * **Preconception Prophylaxis:** For low-risk mothers, the dose is **400 mcg (0.4 mg)**; for high-risk mothers (previous NTD, on anticonvulsants, or diabetic), the dose is **4 mg to 5 mg**. * **Timing:** Folic acid must be started at least **1 month prior to conception** and continued through the first trimester (12 weeks). * **Lemon & Banana Signs:** On ultrasound, the "Lemon sign" (scalloping of frontal bones) and "Banana sign" (curved cerebellum) are classic markers for spina bifida.

Practice by Chapter

Preconception Counseling

Practice Questions

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

Practice Questions

Fetal Growth Assessment

Practice Questions

High-Risk Pregnancy Identification

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Antenatal Complications Management

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Psychosocial Aspects of Pregnancy

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