Prenatal Care — MCQs

Prenatal Care Indian Medical PG Practice Questions and MCQs

Question 51: Which vitamin is given to pregnant women to prevent neural tube defects?

A. Folic acid (Correct Answer)
B. Vitamin B12
C. Vitamin C
D. Vitamin A

Explanation: **Explanation:** **Folic acid (Vitamin B9)** is the correct answer because it is essential for DNA synthesis and amino acid metabolism. During the first few weeks of pregnancy, the neural tube (which becomes the brain and spinal cord) closes. Folic acid deficiency impairs cell division in the neural plate, leading to **Neural Tube Defects (NTDs)** such as spina bifida and anencephaly. **Analysis of Options:** * **Vitamin B12 (Cobalamin):** While B12 works closely with folate in DNA synthesis, it is not the primary supplement used for NTD prevention. Its deficiency is more commonly associated with megaloblastic anemia and neurological issues. * **Vitamin C (Ascorbic Acid):** This is an antioxidant that aids iron absorption and collagen synthesis but has no direct role in preventing structural neural defects. * **Vitamin A (Retinol):** Excessive intake of Vitamin A (specifically preformed retinol) is actually **teratogenic**, potentially causing craniofacial and cardiac defects. It is generally avoided in high doses during pregnancy. **Clinical Pearls for NEET-PG:** * **Timing:** Folic acid must be started **pre-conceptionally** (at least 1 month before) and continued through the **first trimester** (up to 12 weeks) to be effective, as the neural tube closes by the 28th day of gestation. * **Dosage:** * **Low risk:** 400 mcg (0.4 mg) daily. * **High risk** (previous child with NTD, mother on anti-epileptics like Valproate, or diabetic mothers): **5 mg daily.** * **Drug Interaction:** Anticonvulsants (Phenytoin, Carbamazepine) and Methotrexate act as folate antagonists, increasing the risk of NTDs.

Question 52: What is the best method for localizing the placenta?

A. Vaginal examination
B. Amniography
C. Uteroscopy
D. Ultrasonogram (Correct Answer)

Explanation: **Explanation:** The localization of the placenta is a critical step in prenatal care, primarily to rule out **Placenta Previa**. **Why Ultrasonogram (USG) is the best method:** Ultrasonography is the **gold standard** and the investigation of choice for placental localization. It is non-invasive, safe (no ionizing radiation), easily available, and highly accurate (95–98% sensitivity). Transvaginal Sonography (TVS) is considered superior to Transabdominal Sonography (TAS) as it provides better visualization of the internal os and the lower uterine segment, even in cases of a posterior placenta. **Why other options are incorrect:** * **Vaginal Examination:** This is **strictly contraindicated** in cases of suspected placenta previa (unless performed as a "Double Setup" in an OT) because it can provoke massive, life-threatening hemorrhage by disturbing the placental attachment. * **Amniography:** This involves injecting radiopaque dye into the amniotic sac. It is an obsolete, invasive technique that carries risks of infection, fetal injury, and radiation exposure. * **Uteroscopy:** This is not a standard tool for placental localization. It is invasive and carries a high risk of rupturing membranes or causing hemorrhage. **High-Yield Clinical Pearls for NEET-PG:** * **Investigation of Choice:** Transvaginal Ultrasound (TVS) is safer and more accurate than TAS for measuring the distance between the placental edge and the internal os. * **Placental Migration:** The placenta may appear "low-lying" in the second trimester but "move" away from the os as the lower uterine segment develops (Trohotropism). * **MRI:** Reserved for suspected **Placenta Accreta Spectrum** when USG results are inconclusive. * **Warning:** Never perform a per-vaginal (PV) exam in a pregnant woman with bleeding (APH) until placenta previa is ruled out by USG.

Question 53: What is the best serological marker for Down syndrome in the first trimester?

A. Nuchal translucency
B. Skeletal abnormalities
C. beta-hCG (Correct Answer)
D. Serum estriol

Explanation: **Explanation:** In the first trimester (11–13.6 weeks), the standard screening for Down syndrome (Trisomy 21) is the **Combined Test**, which includes maternal age, fetal nuchal translucency (NT), and two biochemical markers: **Pregnancy-associated plasma protein A (PAPP-A)** and **free beta-hCG**. **Why beta-hCG is correct:** Among the biochemical markers, **free beta-hCG is significantly elevated** in pregnancies affected by Down syndrome. Conversely, PAPP-A levels are characteristically decreased. While both are used, beta-hCG is the primary serological marker associated with an increased risk of Trisomy 21 in the first trimester. **Analysis of Incorrect Options:** * **A. Nuchal translucency (NT):** While NT is the most sensitive *ultrasound* marker for Down syndrome, the question specifically asks for a **serological** (blood) marker. * **B. Skeletal abnormalities:** These (such as a short femur or humerus) are "soft markers" typically identified during the second-trimester anomaly scan (18–20 weeks), not the first trimester. * **D. Serum estriol (uE3):** Unconjugated estriol is a component of the **Triple or Quadruple marker test**, which is performed in the **second trimester** (15–20 weeks). In Down syndrome, estriol levels are decreased. **High-Yield Clinical Pearls for NEET-PG:** * **First Trimester (Combined Test):** ↑ beta-hCG, ↓ PAPP-A, ↑ NT. * **Second Trimester (Quad Test):** ↑ beta-hCG, ↑ Inhibin A, ↓ AFP, ↓ uE3 (Mnemonic: **HI** is **High**—**H**CG and **I**nhibin are elevated). * **Confirmatory Test:** Chorionic Villus Sampling (10–13 weeks) or Amniocentesis (15–20 weeks). * **NIPT (Cell-free DNA):** The most sensitive screening tool overall (detection rate >99%), but it is not categorized as a traditional "serological marker" in this context.

Question 54: Which of the following is NOT a cause of first-trimester abortion?

A. Rubella infection
B. Syphilis infection
C. Defective germplasm
D. None of the above (Correct Answer)

Explanation: **Explanation:** The correct answer is **None of the above** because all the listed options (Rubella, Syphilis, and Defective Germplasm) are recognized causes of spontaneous abortion in the first trimester. 1. **Defective Germplasm (Option C):** This is the **most common cause** of first-trimester abortions (responsible for over 50-60% of cases). It refers to chromosomal abnormalities, most frequently **Autosomal Trisomies** (Trisomy 16 being the most common), followed by Monosomy X (Turner syndrome) and Polyploidy. 2. **Infections (Options A & B):** While many infections are associated with late-term complications, both **Rubella** and **Syphilis** can lead to early pregnancy loss. * **Rubella:** Known for its teratogenic effects, a primary infection in the first trimester can lead to severe fetal damage or death, resulting in a spontaneous abortion. * **Syphilis:** Classically associated with second-trimester miscarriages and stillbirths, *Treponema pallidum* can cross the placenta as early as 6–9 weeks of gestation, potentially causing first-trimester loss. **Clinical Pearls for NEET-PG:** * **Most common cause of spontaneous abortion:** Genetic/Chromosomal factors (Defective germplasm). * **Most common specific chromosomal anomaly:** Trisomy 16. * **Most common single chromosomal anomaly:** Monosomy X (45,X). * **Timing:** 80% of spontaneous abortions occur within the first 12 weeks (first trimester). * **Infections:** While Rubella and Syphilis cause abortion, **Ureaplasma urealyticum** and **Mycoplasma hominis** are the most frequently implicated vaginal organisms in recurrent early pregnancy loss.

Question 55: Which of the following is not a risk factor for a woman to develop gestational diabetes?

A. Previous macrosomic baby
B. Previous history of gestational diabetes
C. Both parents have diabetes
D. Working mother (Correct Answer)

Explanation: **Explanation:** Gestational Diabetes Mellitus (GDM) is defined as carbohydrate intolerance resulting in hyperglycemia with onset or first recognition during pregnancy. The development of GDM is primarily linked to maternal insulin resistance and genetic predisposition. **Why "Working mother" is the correct answer:** Occupational status or being a "working mother" is not an established medical risk factor for GDM. While high-stress environments or sedentary desk jobs can indirectly influence health, the act of being employed does not inherently alter glucose metabolism or insulin sensitivity in the way that biological and historical factors do. **Analysis of Incorrect Options (Risk Factors):** * **Previous macrosomic baby:** Delivering a baby weighing >4kg (macrosomia) is a classic indicator of past undiagnosed glucose intolerance. It significantly increases the risk of GDM in subsequent pregnancies. * **Previous history of GDM:** This is one of the strongest predictors. Women with a history of GDM have a 30–50% chance of recurrence in future pregnancies. * **Family history of diabetes (Both parents):** Type 2 Diabetes has a strong genetic component. Having a first-degree relative (especially both parents) with DM indicates a genetic predisposition to insulin resistance, which is exacerbated by the diabetogenic hormones of pregnancy (e.g., Human Placental Lactogen). **High-Yield Clinical Pearls for NEET-PG:** * **Screening:** In India, the **DIPSI (Diabetes in Pregnancy Study Group India)** guidelines recommend a single-step test: 75g oral glucose load regardless of last meal; GDM is diagnosed if 2-hour plasma glucose is **≥140 mg/dL**. * **Other Risk Factors:** Maternal age >35 years, BMI >30 kg/m², Polycystic Ovary Syndrome (PCOS), and belonging to high-risk ethnic groups (South Asians). * **Best Initial Management:** Medical Nutrition Therapy (MNT) and exercise for 1–2 weeks. If targets are not met, **Insulin** is the gold standard drug of choice.

Question 56: The bluish discoloration of vaginal mucosa in the 8th week of pregnancy is called?

A. Jacquemier's sign (Correct Answer)
B. Goodell's sign
C. Hegar's sign
D. Palmer's sign

Explanation: **Explanation:** The correct answer is **Jacquemier's sign**. This clinical finding refers to the bluish or purplish discoloration of the vaginal mucosa, which typically appears around the 8th week of pregnancy. It is caused by increased vascularity and venous congestion in the pelvic organs due to rising estrogen levels. **Why the other options are incorrect:** * **Goodell’s sign:** This refers to the **softening of the cervix**, which occurs around the 6th week of pregnancy. Before pregnancy, the cervix feels like the tip of the nose; during pregnancy, it feels like the lips. * **Hegar’s sign:** This is the softening of the **isthmus** (the lower uterine segment). On bimanual examination, the upper part of the uterus and the cervix feel like two separate entities because the intervening isthmus is so soft. It is usually detectable between 6–10 weeks. * **Palmer’s sign:** This refers to regular, rhythmic, and painless **uterine contractions** that can be felt during a bimanual examination as early as 4–8 weeks of gestation. **High-Yield Clinical Pearls for NEET-PG:** 1. **Chadwick’s Sign:** Often used interchangeably with Jacquemier's sign, it specifically refers to the bluish discoloration of the **vestibule and anterior vaginal wall**. 2. **Osiander’s Sign:** Increased pulsation felt through the lateral vaginal fornices due to increased vascularity (8th week). 3. **Piskacek’s Sign:** Asymmetrical enlargement of the uterus if implantation occurs near one of the cornua. 4. **Ladins Sign:** Softening of the anterior midline of the uterus at the cervico-uterine junction (6th week).

Question 57: Diagnosis of Down syndrome at 11 weeks gestation can be assessed by:

A. Ultrasonography
B. Aminocentesis
C. Chorionic villous biopsy (Correct Answer)
D. Doppler ultrasound

Explanation: **Explanation:** The diagnosis of Down syndrome (Trisomy 21) requires a **definitive genetic analysis** (karyotyping or FISH) to identify the extra chromosome 21. 1. **Why Chorionic Villous Biopsy (CVS) is correct:** CVS is an invasive diagnostic procedure performed between **10 and 13 weeks** of gestation. It involves taking a sample of placental tissue (chorionic villi), which shares the same genetic makeup as the fetus. Since the question specifies **11 weeks**, CVS is the gold-standard diagnostic tool available at this specific gestational age. 2. **Why other options are incorrect:** * **Ultrasonography:** While USG can detect "soft markers" like increased Nuchal Translucency (NT) at 11–13 weeks, it is a **screening tool**, not a diagnostic one. It suggests a risk but cannot confirm the diagnosis. * **Amniocentesis:** This is a definitive diagnostic test, but it is typically performed between **15 and 20 weeks**. Performing it before 15 weeks (early amniocentesis) is avoided due to higher risks of clubfoot (talipes) and pregnancy loss. * **Doppler Ultrasound:** This is used to assess blood flow in maternal and fetal vessels (e.g., Uterine or Umbilical artery) to monitor fetal well-being and growth restriction; it has no role in the primary diagnosis of chromosomal aneuploidies. **High-Yield Clinical Pearls for NEET-PG:** * **First Trimester Screening (Combined Test):** Includes NT scan + PAPP-A + β-hCG (performed between 11–13+6 weeks). * **Definitive Diagnosis:** CVS (10–13 weeks) or Amniocentesis (>15 weeks). * **NIPT (Non-Invasive Prenatal Testing):** Analyzes cell-free fetal DNA in maternal blood; it is the most sensitive screening test but still requires confirmation via CVS or Amniocentesis.

Question 58: What is a blighted ovum?

A. Synaptic knobs
B. Avascular villi (Correct Answer)
C. Intervillous hemorrhage
D. None of the above

Explanation: **Explanation:** A **blighted ovum**, also known as an **anembryonic pregnancy**, occurs when a fertilized egg attaches itself to the uterine wall, but the embryo fails to develop. While the gestational sac forms and grows, the fetal pole is absent. **Why "Avascular Villi" is correct:** In a blighted ovum, the primary defect is the failure of the embryo to develop or its early death. Because the circulatory system of the embryo never establishes or ceases to function almost immediately, there is no fetal blood flow to the chorionic villi. Histopathologically, this manifests as **avascular villi**. The trophoblastic tissue may continue to grow for a short period, but the villi remain fluid-filled and lack fetal capillaries, eventually leading to hydropic changes. **Analysis of Incorrect Options:** * **A. Synaptic knobs:** This is an anatomical term related to neurons (the terminal end of an axon), having no relevance to placental pathology or embryology. * **C. Intervillous hemorrhage:** This refers to bleeding between the chorionic villi in the intervillous space. While it can be seen in various types of abortions or placental abruptions, it is not the defining histopathological feature of a blighted ovum. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** On Ultrasound (TVUS), a blighted ovum is diagnosed when the **Mean Sac Diameter (MSD) is ≥25 mm** without a visible embryo. * **Karyotype:** The most common cause of a blighted ovum is chromosomal abnormalities (autosomal trisomies being the most frequent). * **Clinical Presentation:** Patients often present with "threatened abortion" symptoms (spotting) but have a gestational sac that is "empty" on scan. * **Management:** Options include expectant management, medical evacuation (Misoprostol), or MVA (Manual Vacuum Aspiration).

Question 59: Maternal serum Alpha-fetoprotein is raised in all the following conditions EXCEPT?

A. Spina bifida
B. Multiple pregnancy
C. Omphalocele
D. Down's syndrome (Correct Answer)

Explanation: **Explanation:** Maternal Serum Alpha-Fetoprotein (MSAFP) is a glycoprotein produced initially by the yolk sac and later by the fetal liver. It enters the maternal circulation via the placenta and amniotic fluid. **Why Down’s Syndrome is the Correct Answer:** In **Down’s Syndrome (Trisomy 21)**, MSAFP levels are characteristically **decreased** (usually <0.5 MoM), not raised. This is often associated with decreased levels of Unconjugated Estriol (uE3) and increased levels of hCG and Inhibin-A (the "Quadruple Test" profile). **Analysis of Incorrect Options (Conditions with Raised MSAFP):** * **Spina Bifida (Open Neural Tube Defects):** AFP leaks directly from the exposed fetal tissues into the amniotic fluid and subsequently into the maternal serum. * **Multiple Pregnancy:** Since AFP is produced by the fetus, multiple fetuses result in higher cumulative levels of AFP in the maternal blood. * **Omphalocele (Abdominal Wall Defects):** Similar to NTDs, the lack of skin integrity allows AFP to leak into the amniotic fluid, leading to elevated maternal levels. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most Common Cause of Raised MSAFP:** Underestimation of gestational age (wrong dates). 2. **Raised MSAFP (>2.5 MoM):** Seen in NTDs, abdominal wall defects (Gastroschisis > Omphalocele), multiple gestations, fetal demise, and renal anomalies (Finnish-type nephrosis). 3. **Low MSAFP (<0.5 MoM):** Seen in Down’s syndrome, Trisomy 18 (Edwards syndrome), gestational trophoblastic disease, and maternal obesity. 4. **Screening Window:** The ideal time for MSAFP screening is **15–20 weeks** of gestation.

Question 60: Which marker is increased in amniotic fluid in neural tube defects?

A. Alpha-fetoprotein (Correct Answer)
B. Acetylcholinesterase
C. Beta-hCG
D. All of the above

Explanation: **Explanation:** In neural tube defects (NTDs) such as anencephaly or spina bifida, there is a failure of the neural tube to close. This results in a direct communication between the fetal circulation/cerebrospinal fluid and the amniotic fluid. **Alpha-fetoprotein (AFP)**, a glycoprotein synthesized by the fetal yolk sac and liver (analogous to adult albumin), leaks through these open defects into the amniotic fluid, leading to significantly elevated levels. **Analysis of Options:** * **A. Alpha-fetoprotein (Correct):** It is the primary screening marker. Elevated levels in amniotic fluid (AFAFP) or maternal serum (MSAFP) are highly suggestive of open NTDs, abdominal wall defects (omphalocele/gastroschisis), or multiple gestations. * **B. Acetylcholinesterase (AChE):** While AChE is also increased in NTDs and is actually **more specific** than AFP, it is typically used as a **confirmatory test** rather than the primary marker for initial screening. In many standardized contexts, AFP remains the classic answer for the "marker increased." * **C. Beta-hCG:** This marker is used in the Triple/Quadruple screen for chromosomal anomalies. It is **increased in Down Syndrome** (Trisomy 21) but is not a marker for neural tube defects. **NEET-PG High-Yield Pearls:** 1. **Most common cause of elevated MSAFP:** Underestimation of gestational age (dating error). 2. **Specific Confirmatory Test:** If AFAFP is high, the presence of **Acetylcholinesterase (AChE)** in amniotic fluid confirms an open NTD. 3. **Low AFP levels:** Associated with Down Syndrome (Trisomy 21) and Trisomy 18. 4. **Folic Acid:** 0.4 mg/day (low risk) or 4 mg/day (high risk/previous NTD) prevents 70% of NTDs.

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

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Fetal Growth Assessment

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High-Risk Pregnancy Identification

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Antenatal Complications Management

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Psychosocial Aspects of Pregnancy

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