Prenatal Care Practice Questions

Q: Prenatal diagnosis at 16 weeks of pregnancy can be performed using which of the following methods?

Amniocentesis for amniotic fluid. ### Explanation The correct answer is **A. Amniocentesis for amniotic fluid**. **1. Why Amniocentesis is Correct:** Amniocentesis is the gold-standard invasive prenatal diagnostic procedure performed between **15 and 20 weeks** of gestation (ideally at 16 weeks). At this stage, there is sufficient amniotic fluid (approx. 150-200 mL) to safely withdraw 15-20 mL for fetal karyotyping, biochemical analysis, and DNA studies. The procedure involves ultrasound-guided needle aspiration of fluid containing desquamated fetal cells (amniocytes). **2. Why the Other Options are Incorrect:** * **B. Maternal blood for AFP levels:** This is a **screening test**, not a diagnostic test. While Maternal Serum Alpha-Fetoprotein (MSAFP) is measured between 15-20 weeks to screen for Neural Tube Defects (NTDs), a definitive diagnosis requires imaging or invasive testing. * **C. Chorionic Villus Sampling (CVS):** This is typically performed in the **first trimester**, between **10 and 13 weeks**. Performing it at 16 weeks is technically difficult and carries a higher risk of complications compared to amniocentesis. * **D. Fetal blood sampling (Cordocentesis):** Also known as Percutaneous Umbilical Blood Sampling (PUBS), this is usually performed **after 18 weeks** of gestation when the umbilical vein is large enough to be punctured safely. **3. High-Yield Clinical Pearls for NEET-PG:** * **Early Amniocentesis:** Performed before 15 weeks; it is generally avoided due to a higher risk of clubfoot (talipes equinovarus) and pregnancy loss. * **CVS vs. Amniocentesis:** CVS cannot diagnose Neural Tube Defects (as it doesn't measure AFP); Amniocentesis can. * **Most common complication:** For both procedures, the most common risk is fetal loss (approx. 0.5% for amniocentesis; 1% for CVS). * **Rh-Negative Mothers:** Always administer Anti-D immunoglobulin after any invasive prenatal procedure to prevent isoimmunization.

Q: Folic acid is typically recommended during which trimester of pregnancy?

First. **Explanation:** **Why the First Trimester is Correct:** Folic acid (Vitamin B9) is critical during the **first trimester**, specifically during the first 28 days of gestation, because this is the period of **organogenesis** and **neural tube closure**. The neural tube closes by the 28th day after conception—often before a woman realizes she is pregnant. Adequate folate levels are essential for DNA synthesis and amino acid metabolism; a deficiency leads to **Neural Tube Defects (NTDs)** such as spina bifida and anencephaly. To be most effective, supplementation should ideally begin **pre-conceptionally** (at least 1 month prior) and continue through the first 12 weeks of pregnancy. **Why Other Options are Incorrect:** * **Second and Third Trimesters:** While folic acid is often continued as part of Iron-Folic Acid (IFA) tablets to prevent maternal megaloblastic anemia, its primary role in preventing structural congenital malformations (NTDs) is over by the end of the first trimester. * **Throughout Pregnancy:** While not harmful, the "typical" recommendation specifically targeting the prevention of NTDs focuses on the peri-conceptional period and the first trimester. **High-Yield Clinical Pearls for NEET-PG:** * **Standard Dose:** 400 mcg (0.4 mg) daily for low-risk pregnancies. * **High-Risk Dose:** 4 mg (4000 mcg) daily if there is a previous history of a child with NTD, maternal diabetes, or use of anti-epileptic drugs (e.g., Valproate). * **IFA Prophylaxis (Government of India/Anemia Mukt Bharat):** 100 mg elemental iron + 500 mcg folic acid daily for 180 days, starting from the second trimester (14 weeks). * **Megaloblastic Anemia:** Folic acid deficiency is the most common cause of megaloblastic anemia in pregnancy.

Q: Alpha-fetoprotein (AFP) levels are associated with various clinical aspects in obstetrics. All of the following conditions are associated with high maternal serum AFP levels, EXCEPT:

Down syndrome (Trisomy 21). **Explanation:** Maternal Serum Alpha-Fetoprotein (MSAFP) is a glycoprotein produced initially by the yolk sac and later by the fetal liver. It peaks in maternal circulation between 16–18 weeks of gestation. Understanding the direction of AFP levels is crucial for prenatal screening. **Why Down Syndrome is the Correct Answer:** In pregnancies affected by **Down syndrome (Trisomy 21)**, MSAFP levels are characteristically **decreased** (usually <0.5 MoM). This is often accompanied by low unconjugated estriol (uE3) and elevated levels of Beta-hCG and Inhibin-A (the "Quadruple Test" pattern). **Analysis of Incorrect Options (Conditions with High AFP):** * **Multiple Pregnancy:** More than one fetus results in a higher cumulative production of AFP, leading to elevated maternal serum levels. * **Intrauterine Fetal Demise (IUFD):** Fetal death leads to the breakdown of fetal tissues and skin barriers, causing a massive leak of AFP into the amniotic fluid and subsequently into the maternal circulation. * **Congenital Renal Anomalies:** Conditions like Finnish-type nephrosis or posterior urethral valves cause excessive protein (AFP) to be excreted via fetal urine into the amniotic fluid, raising maternal levels. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of elevated MSAFP:** Underestimation of gestational age (wrong dates). * **Highest elevation of AFP:** Seen in **Anencephaly** and Open Neural Tube Defects (ONTD) due to direct exposure of fetal vessels/tissues. * **Low AFP levels:** Associated with Trisomy 21, Trisomy 18 (Edwards syndrome), Molar pregnancy, and Maternal Obesity. * **Abdominal Wall Defects:** Both Omphalocele and Gastroschisis cause high AFP, but levels are typically higher in Gastroschisis.

Q: At what gestational age can ultrasound detect cardiac activity?

5-6 weeks. **Explanation:** In early pregnancy, the detection of cardiac activity is a critical milestone for confirming a viable intrauterine pregnancy. On a high-resolution **Transvaginal Ultrasound (TVS)**, the fetal heart pole and cardiac flickering can typically be visualized when the embryo reaches a crown-rump length (CRL) of **2–4 mm**, which corresponds to a gestational age of **5.5 to 6 weeks**. * **Option A (5-6 weeks):** This is the correct window. By the end of the 5th week, the primitive heart tube begins to beat. TVS can reliably detect this activity between 5.5 and 6 weeks. * **Option B & C (6-8 weeks):** While cardiac activity is certainly visible during this time, these options are "late." By 6.5 to 7 weeks, cardiac activity should be visible even on Transabdominal Ultrasound (TAS). * **Option D (8-10 weeks):** This is well beyond the initial detection period. By this stage, the embryo has developed into a fetus with clearly identifiable limbs and movement. **High-Yield Clinical Pearls for NEET-PG:** 1. **Discriminatory Milestones (TVS):** * **Gestational Sac:** 4.5–5 weeks. * **Yolk Sac:** 5–5.5 weeks (First intragestational structure seen). * **Cardiac Activity:** 5.5–6 weeks. 2. **The "Rule of 10":** If using **Transabdominal Ultrasound (TAS)**, milestones are generally delayed by about 1 week compared to TVS. 3. **Diagnosis of Pregnancy Failure:** According to the SRU criteria, pregnancy is considered non-viable if there is a **CRL ≥ 7 mm** with no cardiac activity on TVS. 4. **Heart Rate:** In early pregnancy (6 weeks), the normal fetal heart rate is approximately 100–115 bpm, increasing to 140–170 bpm by 9 weeks.

Q: A 35-year-old female with a previous history of a child with Down's syndrome presents with 18 weeks of amenorrhea. What is the investigation of choice to rule out Down's syndrome in the present pregnancy?

Amniocentesis. **Explanation:** The patient is currently at **18 weeks of gestation** and has a high-risk history (previous child with Down’s syndrome). To "rule out" a chromosomal anomaly, a **diagnostic test** (karyotyping) is required rather than a screening test. **1. Why Amniocentesis is the Correct Answer:** Amniocentesis is the gold-standard diagnostic procedure performed between **15–20 weeks** of gestation. Since the patient is at 18 weeks, this is the most appropriate window. It involves aspirating amniotic fluid to obtain fetal desquamated cells for karyotyping, providing a definitive diagnosis of trisomy 21. **2. Why the other options are incorrect:** * **Triple Test (Option A):** This is a **screening test** (measuring AFP, hCG, and uE3). Screening tests only provide a risk probability and cannot "rule out" or confirm the diagnosis. * **Chorionic Villous Biopsy (CVS) (Option D):** While CVS is a diagnostic test, it is ideally performed between **10–13 weeks**. At 18 weeks, the placenta is more formed, and amniocentesis is technically safer and preferred over CVS. * **Cordocentesis (Option C):** Also known as Percutaneous Umbilical Blood Sampling (PUBS), it is usually performed after **18–20 weeks**. However, it carries a higher risk of fetal loss (1–2%) compared to amniocentesis (0.5%) and is generally reserved for rapid karyotyping or fetal blood disorders. **Clinical Pearls for NEET-PG:** * **Best time for Amniocentesis:** 15–20 weeks (Early amniocentesis <14 weeks is avoided due to risk of clubfoot/talipes). * **Most common complication of Amniocentesis:** Premature rupture of membranes (PROM) and fetal loss (0.5%). * **Combined Screening (1st Trimester):** Nuchal translucency (NT) + PAPP-A + hCG (performed at 11–13+6 weeks). * **Quadruple Test:** Triple test + Inhibin A (best screening sensitivity in the 2nd trimester).

Q: Screening for gestational diabetes mellitus (GDM) is not required for which of the following conditions?

Previous pre-eclampsia. **Explanation:** The screening for Gestational Diabetes Mellitus (GDM) is primarily targeted at identifying women with specific risk factors that suggest underlying insulin resistance or metabolic dysfunction. **Why Option D is correct:** While **Pre-eclampsia** is a *complication* of GDM, a history of pre-eclampsia in a previous pregnancy is not a standalone indication for GDM screening in the current pregnancy according to standard guidelines (like DIPSI or IADPSG). Pre-eclampsia is primarily a vascular and endothelial disorder. While it shares some metabolic risk factors with GDM (like obesity), it does not directly imply a high risk of glucose intolerance in the same way that fetal macrosomia or unexplained fetal loss does. **Why the other options are wrong:** * **A. Previous macrosomic infant (>4kg):** This is a classic hallmark of fetal hyperinsulinemia caused by maternal hyperglycemia. It indicates a high risk of recurrent GDM. * **B. Previous congenital malformation:** Poorly controlled pre-gestational or early gestational diabetes is teratogenic (e.g., Sacral agenesis, Cardiac defects). A history of malformation necessitates early screening to rule out undiagnosed Type 2 DM. * **C. Previous stillbirth:** Unexplained third-trimester stillbirth is a known complication of maternal hyperglycemia due to fetal acidemia and hypoxia. **High-Yield Clinical Pearls for NEET-PG:** * **DIPSI Guidelines (India):** Screening is performed at the first prenatal visit and repeated at 24–28 weeks. A single-step test using **75g glucose** is used; a 2-hour plasma glucose **≥140 mg/dL** is diagnostic of GDM, regardless of the fasting state. * **Risk Factors for GDM:** BMI >30 kg/m², Age >35, First-degree relative with DM, PCOS, and history of GDM in a previous pregnancy. * **Most common malformation in GDM:** Ventricular Septal Defect (VSD). * **Most specific malformation in GDM:** Caudal Regression Syndrome (Sacral Agenesis).

Question 1

A 31-year-old G3P2L2 presents at 34 weeks gestation with baseline blood pressures of 100-110/60-70 mmHg. She has bilateral pedal edema. Her urine dipstick shows trace protein, and her current blood pressure is 115/75 mmHg. On physical examination, there is pitting edema of both legs without any calf tenderness. What is the best management now?

Accepted Answer

This is a normal finding of pregnancy, and no treatment is needed.

Answer

Administer furosemide to reduce the swelling.

Answer

Perform urgent venous Doppler studies to rule out deep vein thrombosis.

Answer

Admit the patient and rule out preeclampsia.

Question 2

Prenatal diagnosis at 16 weeks of pregnancy can be performed using which of the following methods?

Accepted Answer

Amniocentesis for amniotic fluid

Answer

Maternal blood for AFP levels

Answer

Chorionic villus sampling

Answer

Fetal blood sampling

Question 3

While evaluating the heart of a 29-year old primigravida at term, you notice that there is an S2 and S3 which are easily audible and a systolic ejection murmur greater during inspiration. What do you recognize?

Accepted Answer

All findings recorded are normal changes in pregnancy.

Answer

The presence of S3 is abnormal.

Answer

The systolic ejection murmur is unusual in a pregnant woman at term.

Answer

Wide pulse pressure is rare in pregnant women.

Question 4

A health-conscious vegetarian patient regularly ingests mega doses of vitamins and herbal therapies daily. She is planning pregnancy and seeks advice on diet and nutrition. Which of the following statements regarding diet recommendations in pregnancy is true?

Accepted Answer

During pregnancy, the majority of consumed protein should be supplied from animal sources.

Answer

Herbal medications are natural, so there is no reason to avoid these dietary supplements during pregnancy.

Answer

Routine supplementation of vitamin A is necessary during pregnancy as dietary intake alone is insufficient.

Answer

During pregnancy, vegetarians obtain sufficient vitamin B12 in their diet for the fetus.

Question 5

Folic acid is typically recommended during which trimester of pregnancy?

Accepted Answer

First

Answer

Second

Answer

Third

Answer

Throughout pregnancy

Question 6

Alpha-fetoprotein (AFP) levels are associated with various clinical aspects in obstetrics. All of the following conditions are associated with high maternal serum AFP levels, EXCEPT:

Accepted Answer

Down syndrome (Trisomy 21)

Answer

Multiple pregnancy

Answer

Intrauterine fetal demise (IUFD)

Answer

Congenital renal anomalies

Question 7

A 21-year-old female presents with amenorrhea of 5 weeks. Her urine pregnancy test is positive. Ultrasound shows a gestational sac and yolk sac within the uterus. No fetal pole or cardiac activity is visible. Crown-rump length (CRL) is 8 mm and mean sac diameter (MSD) is 28 mm. What is the next best step?

Accepted Answer

High probability of nonviable pregnancy; repeat scan after 7 days to confirm.

Answer

Advise medical termination of pregnancy as it is a nonviable pregnancy.

Answer

Consider ectopic pregnancy; administer methotrexate.

Answer

High probability of viable pregnancy; repeat scan after 7 days.

Question 8

At what gestational age can ultrasound detect cardiac activity?

Accepted Answer

5-6 weeks

Answer

6-7 weeks

Answer

7-8 weeks

Answer

8-10 weeks

Question 9

A 35-year-old female with a previous history of a child with Down's syndrome presents with 18 weeks of amenorrhea. What is the investigation of choice to rule out Down's syndrome in the present pregnancy?

Accepted Answer

Amniocentesis

Answer

Triple test

Answer

Cordocentesis

Answer

Chorionic villous biopsy

Question 10

Screening for gestational diabetes mellitus (GDM) is not required for which of the following conditions?

Accepted Answer

Previous pre-eclampsia

Answer

Previous delivery of a macrosomic infant

Answer

Previous delivery with congenital malformation

Answer

Previous stillbirth

Prenatal Care — MCQs

Prenatal Care — MCQs

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