Prenatal Care — MCQs

Prenatal Care Indian Medical PG Practice Questions and MCQs

Question 141: What is a hazard of chorionic villus sampling?

A. Limb abnormality
B. Spina bifida
C. Down's syndrome
D. Abortion (Correct Answer)

Explanation: **Explanation:** **Chorionic Villus Sampling (CVS)** is an invasive prenatal diagnostic procedure performed between **10 and 13 weeks** of gestation to detect chromosomal or genetic abnormalities. **Why Abortion is the Correct Answer:** The most significant and common hazard associated with CVS is **procedure-related pregnancy loss (abortion)**. While the risk has decreased with ultrasound guidance and operator experience, it remains approximately **0.5% to 1%** higher than the baseline risk. It is considered slightly higher than the risk associated with second-trimester amniocentesis. **Analysis of Incorrect Options:** * **Limb Abnormality (Limb Reduction Defects):** While historically associated with CVS, this is only a significant risk if the procedure is performed **before 9-10 weeks** of gestation (due to vascular disruption). When performed during the standard window (10–13 weeks), the risk is negligible. * **Spina Bifida:** This is a neural tube defect (NTD). CVS is used for genetic analysis (karyotyping/DNA) and **cannot** diagnose NTDs. Furthermore, CVS does not cause NTDs. * **Down’s Syndrome:** CVS is a diagnostic tool used to **detect** Down’s syndrome (Trisomy 21); it is not a hazard or a result of the procedure. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Standard CVS is performed at **10–13 weeks**. * **Advantage over Amniocentesis:** Provides results earlier in pregnancy, allowing for safer termination if needed. * **Disadvantage:** Cannot measure Alpha-fetoprotein (AFP); thus, it cannot screen for neural tube defects. * **Confined Placental Mosaicism:** A unique complication of CVS where the placenta has a different genetic makeup than the fetus, potentially leading to false-positive results. * **Rh Isoimmunization:** Anti-D immunoglobulin must be administered to Rh-negative unsensitized women following the procedure.

Question 142: A patient presents for her first initial OB visit, with her last menstrual period approximately 8 weeks ago. She is unsure of her dates due to a history of irregular menses. Which of the following is the most accurate method for dating this pregnancy?

A. Determination of uterine size on pelvic examination
B. Quantitative serum hCG levels
C. Crown-rump length on vaginal ultrasound (Correct Answer)
D. Determination of progesterone levels along with serum hCG levels

Explanation: **Explanation:** The most accurate method for dating a pregnancy, especially in the first trimester, is the **Crown-Rump Length (CRL)** measured via ultrasound. **1. Why Option C is Correct:** In early pregnancy, fetal growth is highly uniform across all pregnancies because it is minimally influenced by external factors (like genetics or placental insufficiency) at this stage. A transvaginal ultrasound (TVUS) can measure the CRL with a margin of error of only **+/- 3 to 5 days**. According to ACOG guidelines, if there is a discrepancy between the Last Menstrual Period (LMP) and the CRL, the ultrasound dating is preferred, particularly in patients with irregular menses where the date of ovulation is uncertain. **2. Why Other Options are Incorrect:** * **Option A:** Uterine size on pelvic exam is subjective and can be confounded by factors such as maternal obesity, uterine fibroids, a retroverted uterus, or multiple gestations. It is far less precise than imaging. * **Option B & D:** While serum hCG and progesterone levels are useful for confirming pregnancy viability or diagnosing an ectopic pregnancy, they cannot be used for dating. hCG levels have a massive "normal" range at any given gestational age, making them unreliable for determining the exact week of pregnancy. **3. NEET-PG Clinical Pearls:** * **First Trimester (up to 13+6 weeks):** CRL is the "Gold Standard" for dating. * **Second Trimester (14–22 weeks):** A composite of Biparietal Diameter (BPD), Head Circumference (HC), Abdominal Circumference (AC), and Femur Length (FL) is used (Accuracy: +/- 7–10 days). * **Third Trimester:** Accuracy drops significantly (+/- 21 days); dating should not be changed based on a third-trimester scan if an earlier scan is available. * **Rule of Thumb:** The earlier the ultrasound, the more accurate the dating.

Question 143: Leopold maneuver is used for what purpose?

A. Delivery of the fetal head
B. Mid-cavity forceps application
C. External podalic version
D. Examination of the maternal abdomen (Correct Answer)

Explanation: **Explanation:** **Leopold Maneuvers** are a systematic series of four manual palpations used to determine fetal lie, presentation, and position by **examining the maternal abdomen**. They are typically performed after 28 weeks of gestation when the fetus is large enough to be palpated. 1. **First Maneuver (Fundal Grip):** Determines which fetal pole (head or breech) occupies the fundus to identify the **lie**. 2. **Second Maneuver (Umbilical/Lateral Grip):** Locates the fetal back and small parts to determine **position**. 3. **Third Maneuver (Pawlik’s Grip):** Confirms the **presentation** and checks if the presenting part is engaged. 4. **Fourth Maneuver (Pelvic Grip):** Determines the **attitude** (flexion/extension) and the degree of descent into the pelvis. **Analysis of Incorrect Options:** * **Option A:** Delivery of the fetal head involves maneuvers like Ritgen’s maneuver, not Leopold’s. * **Option B:** Mid-cavity forceps application requires a vaginal examination to confirm cervical dilation and station, not abdominal palpation. * **Option C:** External Podalic Version (EPV) is a procedure to turn a fetus from breech to cephalic; while it involves abdominal manipulation, Leopold maneuvers are diagnostic, not therapeutic. **High-Yield Clinical Pearls for NEET-PG:** * **Best time to perform:** After 28–30 weeks. * **Prerequisite:** The patient should have an empty bladder to ensure comfort and accuracy. * **Key Distinction:** The **First** maneuver identifies the **Lie**, while the **Third** maneuver identifies the **Presentation**. * The Fourth maneuver is the only one where the examiner faces the patient's feet.

Question 144: A 24-year-old patient presents at 18 weeks of pregnancy with a previous history of a child with Down syndrome. What is the most appropriate next step?

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

Explanation: ### Explanation **1. Why Amniocentesis is the Correct Answer:** The patient is currently at **18 weeks of gestation**, which falls within the ideal window for **Amniocentesis (typically performed between 15–20 weeks)**. Since she has a high-risk history (a previous child with Down syndrome), she requires a **diagnostic test** rather than a screening test to confirm the fetal karyotype. Amniocentesis is the gold-standard diagnostic procedure for chromosomal analysis at this gestational age. **2. Why Other Options are Incorrect:** * **A. Triple Test:** This is a screening test (measuring AFP, hCG, and uE3). In a patient with a prior history of aneuploidy, diagnostic testing is preferred over screening because screening only provides a probability, not a definitive diagnosis. * **B. Chorionic Villous Biopsy (CVS):** While CVS is a diagnostic test, it is performed between **10–13 weeks**. At 18 weeks, the placenta is more developed, and the procedure is no longer the standard of care compared to the safer amniocentesis. * **D. Cordocentesis:** Also known as Percutaneous Umbilical Blood Sampling (PUBS), this is usually performed **after 18–20 weeks**. However, it carries a higher risk of fetal loss (1–2%) and is generally reserved for cases where rapid karyotyping is needed or when amniocentesis results are inconclusive. **3. Clinical Pearls for NEET-PG:** * **Diagnostic vs. Screening:** Always check the gestational age first. * **10–13 weeks:** CVS (Diagnostic) or Combined Test (Screening). * **15–20 weeks:** Amniocentesis (Diagnostic) or Quadruple Test (Screening). * **Risk of Fetal Loss:** Amniocentesis has a lower procedure-related risk (~0.5%) compared to CVS (~1%). * **Most Common Aneuploidy:** Down Syndrome (Trisomy 21). The recurrence risk after one affected child is approximately 1% or the age-specific risk, whichever is higher.

Question 145: Quickening can be felt at approximately how many weeks of gestation?

A. 14 weeks
B. 15 weeks
C. 16 weeks (Correct Answer)
D. 19 weeks

Explanation: **Explanation:** **Quickening** refers to the first perception of fetal movements by the pregnant woman. It is a subjective clinical milestone used to assess fetal well-being and corroborate gestational age. **1. Why 16 weeks is correct:** In clinical practice and for examination purposes, the onset of quickening depends heavily on parity. * **Multigravida** (women who have been pregnant before) typically feel movements earlier, between **16–18 weeks**, because they are familiar with the sensation. * **Primigravida** (first-time mothers) usually perceive it later, between **18–20 weeks**. Since 16 weeks represents the earliest standard clinical threshold for a multigravida to detect movement, it is the most appropriate answer among the choices provided. **2. Analysis of incorrect options:** * **A & B (14 & 15 weeks):** While the fetus begins moving as early as 7–8 weeks (visible on ultrasound), these movements are too weak to be felt through the uterine wall and abdominal muscles at this stage. * **D (19 weeks):** While a primigravida may feel movement at 19 weeks, it is not the *earliest* point at which quickening can be felt. In competitive exams, if a range is applicable, the lower limit for multigravida (16 weeks) is often the sought-after "starting point." **3. Clinical Pearls for NEET-PG:** * **Maternal Perception:** Described as "fluttering," "bubbles," or "butterflies." * **Significance:** If quickening is not felt by 20 weeks, an ultrasound is indicated to confirm fetal viability. * **Factors delaying perception:** Obesity, posterior placenta, and polyhydramnios. * **Rule of thumb:** For dating a pregnancy when the LMP is unknown, add 22 weeks to the date of quickening for primigravidae and 24 weeks for multigravidae.

Question 146: Which of the following is a recent marker for Down syndrome?

A. hCG
B. Alpha fetoprotein
C. Inhibin A (Correct Answer)
D. Estriol

Explanation: **Explanation:** The correct answer is **Inhibin A**. This question focuses on the evolution of maternal serum screening for Down syndrome (Trisomy 21). **1. Why Inhibin A is the correct answer:** Inhibin A is a glycoprotein secreted by the placenta. It was the last marker added to the "Triple Test" (hCG, AFP, and uE3) to create the **Quadruple Screen**, which is performed between 15–20 weeks of gestation. In pregnancies affected by Down syndrome, maternal serum levels of Inhibin A are **significantly elevated**. The addition of Inhibin A increased the detection rate of Down syndrome from approximately 60-70% (Triple Test) to 80-85%, making it the most "recent" standard marker in second-trimester biochemical screening. **2. Why the other options are incorrect:** * **hCG (Human Chorionic Gonadotropin):** This is a classic marker used since the 1980s. While levels are **increased** in Down syndrome, it is not a "recent" addition. * **Alpha-fetoprotein (AFP):** One of the earliest markers identified. Levels are **decreased** in Down syndrome (but increased in neural tube defects). * **Estriol (uE3 - Unconjugated Estriol):** A component of the original Triple Test. Levels are **decreased** in Down syndrome. **Clinical Pearls for NEET-PG:** * **The "HI" Rule:** In Down syndrome, **H**CG and **I**nhibin A are **High**, while the others (AFP, uE3) are low. * **First Trimester Screening:** Includes **PAPP-A** (decreased) and **fβ-hCG** (increased), combined with **Nuchal Translucency (NT)** on ultrasound. * **Combined Test:** NT + PAPP-A + fβ-hCG (Detection rate ~90%). * **Best Screening Tool:** Cell-free DNA (cfDNA/NIPT) is the most sensitive screening method (>99% detection), though it is not a "biochemical marker" in the traditional sense of the Quadruple screen.

Question 147: A woman has previously had 2 anencephalic babies. What is her risk of having a third baby with anencephaly?

A. 0%
B. 10% (Correct Answer)
C. 25%
D. 50%

Explanation: Neural Tube Defects (NTDs), such as anencephaly and spina bifida, follow a **multifactorial inheritance** pattern. This means they result from a complex interaction between multiple genes and environmental factors (like folic acid deficiency). **Explanation of the Correct Answer:** In multifactorial inheritance, the recurrence risk increases with the number of previously affected siblings. * After **one** child with an NTD, the recurrence risk is approximately **2-5%**. * After **two** children with an NTD, the risk significantly increases to approximately **10%**. This 10% risk represents a high-risk category, necessitating aggressive preconception counseling and high-dose folic acid supplementation. **Analysis of Incorrect Options:** * **0%:** Incorrect, as NTDs have a strong genetic predisposition; a history of affected offspring significantly elevates future risk. * **25%:** This risk is characteristic of **Autosomal Recessive** disorders (e.g., Thalassemia). While some rare syndromes involving NTDs (like Meckel-Gruber syndrome) follow this pattern, isolated anencephaly does not. * **50%:** This risk is characteristic of **Autosomal Dominant** disorders (if one parent is affected) or X-linked carriers. **High-Yield Clinical Pearls for NEET-PG:** * **Prevention:** To prevent recurrence in high-risk women (those with a previous affected child), **4 mg (4000 µg)** of Folic Acid is recommended daily, starting 1–3 months before conception. * **Low-risk prophylaxis:** For women with no prior history, the standard dose is **0.4 mg (400 µg)**. * **Screening:** Maternal Serum Alpha-Fetoprotein (**MSAFP**) is elevated in open NTDs like anencephaly. * **Diagnosis:** Ultrasound is the gold standard; anencephaly can be detected as early as 11–14 weeks (the "frog-eye" appearance).

Question 148: At what stage of pregnancy is quickening typically felt?

A. Second month
B. Fifth month (Correct Answer)
C. 10 weeks
D. 12 weeks

Explanation: **Explanation:** **Quickening** refers to the first perception of active fetal movements by the mother. It is a subjective clinical sign used to assess fetal well-being and estimate gestational age. 1. **Why Option B is correct:** In clinical practice, quickening typically occurs between **18 to 20 weeks** of gestation in primigravida (first-time mothers) and slightly earlier, around **16 to 18 weeks**, in multigravida (due to prior experience). Since the fifth month of pregnancy spans from 17 to 20 weeks, it is the most accurate timeframe for the onset of these movements. 2. **Why other options are incorrect:** * **Option A (Second month):** At 8 weeks, the embryo is just becoming a fetus; movements are microscopic and cannot be felt. * **Option C & D (10 & 12 weeks):** While fetal movements can be visualized on ultrasound as early as 8–10 weeks, the fetus is too small and the muscular contractions too weak for the mother to perceive them through the uterine wall and abdominal layers at this stage. **High-Yield Clinical Pearls for NEET-PG:** * **Primigravida:** Quickening at **18–20 weeks**. * **Multigravida:** Quickening at **16–18 weeks**. * **Significance:** Quickening is a "presumptive" sign of pregnancy. It helps in calculating the Expected Date of Delivery (EDD) if the Last Menstrual Period (LMP) is unknown (Add 22 weeks for primigravida; 24 weeks for multigravida). * **Differential Diagnosis:** Intestinal peristalsis or gas bubbles can sometimes be mistaken for quickening (pseudocyesis).

Question 149: What is the typical bitemporal diameter of a fetus?

A. 10.5 weeks
B. 8 weeks (Correct Answer)
C. 11.5 weeks
D. 9.5 weeks

Explanation: **Explanation:** The **Bitemporal Diameter (BTD)** is the distance between the two temporal fossae of the fetal skull. In fetal biometry, it is a specific measurement used primarily in the late first trimester and early second trimester to assess gestational age. **Why 8.0 cm is the correct answer:** In the context of fetal skull dimensions at **term** (full-term fetus), the Bitemporal Diameter typically measures **8.0 cm to 8.2 cm**. It is the shortest transverse diameter of the fetal skull. This measurement is clinically significant because it allows the head to engage in the maternal pelvis more easily compared to the larger Biparietal Diameter (BPD). **Analysis of Incorrect Options:** * **Option A (10.5 cm):** This is the measurement of the **Occipitofrontal diameter (OFD)**, which extends from the root of the nose (glabella) to the external occipital protuberance. * **Option C (11.5 cm):** This corresponds to the **Submentobregmatic diameter**, seen when the head is incomplete extension (face presentation). * **Option D (9.5 cm):** This is the measurement of the **Biparietal Diameter (BPD)**, the largest transverse diameter of the fetal skull, measured between the two parietal eminences. **High-Yield Clinical Pearls for NEET-PG:** * **Shortest Transverse Diameter:** Bitemporal Diameter (8.0 cm). * **Largest Transverse Diameter:** Biparietal Diameter (9.5 cm). * **Shortest Longitudinal Diameter:** Suboccipitobregmatic (9.5 cm) – the presenting diameter in a well-flexed vertex presentation. * **Largest Longitudinal Diameter:** Mentovertical (13.5 cm) – seen in brow presentations, usually necessitating a C-section. * **Engagement:** Occurs when the Biparietal diameter (9.5 cm) crosses the pelvic inlet.

Question 150: What is the recommended dose of anti-D immunoglobulin for antenatal prophylaxis in Rh-negative, non-immunized females?

A. 1000 IU at 28 weeks
B. 1500 IU at 28 weeks (Correct Answer)
C. 500 IU at 28 weeks
D. 1500 IU at 32 weeks

Explanation: **Explanation:** The primary goal of antenatal prophylaxis in Rh-negative, non-immunized (indirect Coombs test negative) women is to prevent **Rh isoimmunization** caused by silent feto-maternal hemorrhages that typically occur in the third trimester. **Why Option B is Correct:** Current international guidelines (RCOG and NICE) and standard obstetric practice recommend a dose of **1500 IU (300 mcg)** of anti-D immunoglobulin. This is ideally administered at **28 weeks of gestation** because the risk of sensitization increases significantly after this period, and the half-life of the immunoglobulin ensures protection until delivery. This single-dose regimen is highly effective in reducing the incidence of maternal sensitization from ~1.5% to 0.2%. **Analysis of Incorrect Options:** * **Option A (1000 IU):** This is an insufficient dose for standard single-dose prophylaxis. While some protocols use two doses of 500 IU (at 28 and 34 weeks), 1000 IU as a single dose is not the standard recommendation. * **Option C (500 IU):** This dose is typically reserved for first-trimester sensitizing events (e.g., miscarriage or ectopic pregnancy before 12-20 weeks) but is inadequate for routine third-trimester prophylaxis. * **Option D (32 weeks):** Waiting until 32 weeks leaves a "window of vulnerability" between 28 and 32 weeks where sensitization could occur. **High-Yield Clinical Pearls for NEET-PG:** * **Standard Dose:** 300 mcg = 1500 IU (Conversion: 1 mcg = 5 IU). * **Postpartum Dose:** 1500 IU must be given within **72 hours** of delivery if the newborn is Rh-positive. * **Kleihauer-Betke Test:** Used to quantify feto-maternal hemorrhage to determine if additional anti-D doses are required (10 mcg covers 0.5 ml of fetal red cells or 1 ml of whole blood). * **Indirect Coombs Test (ICT):** Must be negative before administering prophylaxis; if ICT is positive, the woman is already sensitized, and anti-D is of no use.

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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