Prenatal Care Practice Questions

Q: All of the following antenatal screening tools indicate increased risk of Down syndrome EXCEPT?

Decreased nuchal fold thickness. **Explanation:** The correct answer is **A. Decreased nuchal fold thickness**. In Down syndrome (Trisomy 21), the characteristic finding is an **increased** nuchal fold thickness (measured in the second trimester) or increased nuchal translucency (measured in the first trimester), not a decrease. **Analysis of Options:** * **A. Decreased nuchal fold thickness:** This is the correct "Except" choice. A nuchal fold ≥ 6 mm between 15–20 weeks of gestation is a significant soft marker for Down syndrome. * **B. Increased Inhibin level:** In the second-trimester **Quadruple Screen**, both **Inhibin-A** and **hCG** are **elevated** ("HI" up), while AFP and unconjugated estriol (uE3) are decreased. * **C. Absence of nasal bone:** Hypoplasia or absence of the nasal bone during the 11–14 week ultrasound is a highly specific first-trimester marker for Down syndrome. * **D. Decreased PAPP-A level:** In the first-trimester screening, low levels of Pregnancy-Associated Plasma Protein-A (PAPP-A) combined with high free β-hCG are indicative of Trisomy 21. **High-Yield Clinical Pearls for NEET-PG:** * **First Trimester Screen (11–14 weeks):** Increased Nuchal Translucency (NT), low PAPP-A, and high β-hCG. * **Quadruple Screen (15–20 weeks):** * **Mnemonic "HI":** **H**CG and **I**nhibin-A are **High**. * **AFP and uE3:** Both are **Low**. * **Most sensitive USG marker:** Increased Nuchal Translucency (1st trimester) and Nuchal Fold (2nd trimester). * **Commonest Cardiac Anomaly:** Endocardial cushion defect (AV canal defect).

Q: A 30-year-old G1P0 woman complains of nausea and vomiting for the first 3 months of her pregnancy. She is noted to have a hemoglobin level of 9.0 g/dl and a mean corpuscular volume of 110 fL (normal 90-105 fL). Which of the following is the most likely etiology of the anemia?

Folate deficiency. **Explanation:** The patient presents with **macrocytic anemia** (Hemoglobin 9.0 g/dL, MCV 110 fL) in the first trimester of pregnancy, complicated by nausea and vomiting. **1. Why Folate Deficiency is correct:** Folate deficiency is the **most common cause of megaloblastic anemia** during pregnancy. Pregnancy increases folate requirements five-fold to support rapid fetal growth and placental development. In this case, the patient’s persistent nausea and vomiting (likely *Hyperemesis Gravidarum*) further deplete folate stores due to poor oral intake and malabsorption. Unlike Vitamin B12, folate stores in the body are limited (lasting only 3–4 months), making deficiency manifest quickly under physiological stress. **2. Why the other options are incorrect:** * **Iron Deficiency:** This is the most common cause of anemia in pregnancy overall, but it typically presents as **microcytic hypochromic** anemia (low MCV). * **Vitamin B12 Deficiency:** While it also causes macrocytic anemia, it is rare in pregnancy because B12 stores are vast (lasting 3–5 years) and are usually only depleted in strict vegans or patients with gastric bypass/pernicious anemia. * **Physiologic Anemia:** This occurs due to a disproportionate increase in plasma volume compared to red cell mass. However, it is a **normocytic** anemia (normal MCV) and usually manifests more significantly in the second trimester. **Clinical Pearls for NEET-PG:** * **MCV >100 fL** in pregnancy should always trigger a workup for Megaloblastic Anemia. * **Peripheral Smear:** Look for hypersegmented neutrophils (earliest sign). * **Prophylaxis:** The WHO recommends **400 µg (0.4 mg)** of folic acid daily for all pregnant women to prevent Neural Tube Defects (NTDs). * **High-risk dose:** Women with a previous child with NTD or those on anti-epileptics require **4 mg** daily.

Q: Which clotting factor is not increased in pregnancy?

Factor 11. **Explanation:** Pregnancy is a **hypercoagulable state** characterized by an increase in most procoagulant factors, a decrease in natural anticoagulants, and a reduction in fibrinolytic activity. This physiological adaptation serves to minimize blood loss during placental separation at delivery. **Why Factor 11 is the Correct Answer:** While most clotting factors rise during pregnancy, **Factor XI (11) and Factor XIII (13)** are notable exceptions. Factor XI levels actually **decrease** (by approximately 20-30%) or remain unchanged during pregnancy. Factor XIII also decreases significantly, reaching about 50% of non-pregnant levels by term. **Analysis of Incorrect Options:** * **Factor 2 (Prothrombin):** Levels of Factor II show a mild to moderate **increase** during pregnancy. * **Factor 7:** This factor shows the most dramatic rise among all clotting factors, often increasing by up to 100-200% of pre-pregnancy levels. * **Factor 10:** Along with Factors VII, VIII, IX, and XII, Factor X levels **increase** significantly to facilitate the clotting cascade. **High-Yield NEET-PG Pearls:** * **Factors that Increase:** I (Fibrinogen - increases by 50%), II, VII, VIII, IX, X, and XII. * **Factors that Decrease:** XI, XIII, and **Antithrombin III**. * **Protein S:** Levels of **Free Protein S decrease** significantly (a common exam trap), while Protein C remains relatively unchanged. * **Fibrinogen:** It is the most significantly increased factor by mass (reaching 400-600 mg/dL). * **ESR:** The Erythrocyte Sedimentation Rate (ESR) is physiologically **increased** in pregnancy due to the rise in fibrinogen.

Q: At what gestational age is the following procedure ideally performed?

10-13 weeks. ***10-13 weeks*** - **Chorionic Villus Sampling (CVS)** is ideally performed at 10-13 weeks gestation for early **genetic diagnosis** and **chromosomal abnormalities**. - This timing allows for **first-trimester screening** while avoiding **limb defects** associated with earlier procedures and ensuring adequate **chorionic villi** development. *13-15 weeks* - This timing is **too late** for optimal CVS as the **chorionic villi** begin to regress and become less accessible. - **Amniocentesis** is the preferred procedure during this period (15-20 weeks) rather than CVS. *20-24 weeks* - This gestational age is appropriate for **detailed anatomical ultrasound** and **amniocentesis** for genetic testing. - CVS performed this late would be **technically challenging** and **unnecessary** as amniocentesis provides better **amniotic fluid sampling**. *24 weeks onwards* - This timing is used for **cordocentesis (PUBS)** - **percutaneous umbilical blood sampling** for fetal blood analysis. - CVS at this stage is **not indicated** as the **placental architecture** has changed and other diagnostic methods are more appropriate.

Q: Which of the following statements is FALSE regarding chorionic villus sampling?

Strongly associated with faciomandibular defects. **Explanation:** Chorionic Villus Sampling (CVS) is a prenatal diagnostic procedure used to obtain placental tissue for genetic analysis. **1. Why Option A is the False Statement:** While early CVS (performed **before 9 weeks** of gestation) has been associated with limb reduction defects and oromandibular-hypogenesis syndromes, it is **not "strongly associated"** with these defects when performed at the standard clinical timing. Modern practice ensures CVS is done after 10 weeks, making the risk of such anomalies extremely low (comparable to the baseline population risk). Therefore, stating it is "strongly associated" is clinically inaccurate. **2. Analysis of Other Options:** * **Option B:** The standard window for CVS is **10–13 weeks** (often cited as 10–12 weeks in exams). Performing it earlier increases the risk of limb defects, while performing it later is technically feasible but usually replaced by amniocentesis. * **Option C:** CVS is an invasive procedure that carries a risk of feto-maternal hemorrhage. Therefore, **Anti-D prophylaxis** is mandatory for all Rh-negative, non-sensitized women to prevent isoimmunization. * **Option D:** The primary indication for CVS is the **diagnosis of genetic and chromosomal disorders** (e.g., Down syndrome, Thalassemia) via karyotyping or DNA analysis. Note: It cannot diagnose Neural Tube Defects (NTDs), as that requires amniotic fluid AFP levels. **High-Yield Clinical Pearls for NEET-PG:** * **CVS vs. Amniocentesis:** CVS provides earlier results (1st trimester) but cannot detect NTDs. * **Procedure-related pregnancy loss:** Approximately 0.5–1%. * **Techniques:** Can be performed Transabdominally (most common) or Transcervically. * **Confined Placental Mosaicism:** A unique pitfall of CVS where chromosomal abnormalities are found in the placenta but not in the fetus.

Q: At what value for a one-hour glucose challenge test would you recommend a standard glucose tolerance test?

140 mg/dL. **Explanation:** The screening for Gestational Diabetes Mellitus (GDM) typically follows a two-step approach. The first step is the **Glucose Challenge Test (GCT)**, which involves administering 50g of oral glucose regardless of the time of the last meal. 1. **Why 140 mg/dL is correct:** According to ACOG (American College of Obstetricians and Gynecologists) and standard obstetric guidelines, a plasma glucose value of **≥140 mg/dL (7.8 mmol/L)** measured one hour after the 50g load is considered a positive screen. This threshold identifies approximately 80% of women with GDM. If the GCT is positive, the patient must proceed to the diagnostic 3-hour 100g Oral Glucose Tolerance Test (OGTT). 2. **Analysis of Incorrect Options:** * **120 mg/dL:** This value is too low and would result in an excessive number of false positives, leading to unnecessary diagnostic testing. * **150 mg/dL:** While some clinicians use 130 or 135 mg/dL to increase sensitivity (detecting up to 90% of GDM cases), 150 mg/dL is too high as a starting threshold and would miss many cases of GDM. * **160 mg/dL:** This is significantly above the screening cutoff. However, it is worth noting that if a GCT value is **≥200 mg/dL**, GDM is often diagnosed directly without needing the second-step OGTT. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Screening is routinely performed between **24–28 weeks** of gestation. * **DIPSI Guidelines (India):** In India, the DIPSI (Diabetes in Pregnancy Study Group India) criteria are often used. It uses a **75g glucose load**, and a 2-hour value **≥140 mg/dL** is diagnostic of GDM in a single step. * **High-Risk Patients:** If risk factors are present (e.g., obesity, previous GDM, family history), screening should be done at the **first prenatal visit**.

Q: Which of the following embryonic structures is the earliest ultrasonographically visible indicator of pregnancy?

Gestational sac. **Explanation:** The earliest ultrasonographically visible indicator of an intrauterine pregnancy is the **Gestational Sac**. It typically appears at approximately **4.5 to 5 weeks** of gestational age (menstrual age) using transvaginal sonography (TVS). It is seen as a small, eccentric fluid collection within the thickened decidua, often characterized by the "Double Decidual Sac sign," which helps differentiate it from a pseudogestational sac. **Analysis of Options:** * **Gestational Sac (Correct):** The first sign, appearing at 4.5–5 weeks. It grows at a rate of approximately 1 mm per day. * **Fetal Pole:** Also known as the embryo, it is the next structure to appear after the yolk sac. It is usually visible at **5.5 to 6 weeks** via TVS. * **Fetal Heart Activity:** This is the first sign of a viable pregnancy. It is typically detected when the fetal pole reaches 2–4 mm in length, usually around **6 weeks** of gestation. * **Fetal Skeleton:** This is a late finding. Mineralization of the fetal skeleton begins at approximately 8 weeks but is generally not clearly visible on routine ultrasound until the **second trimester** (around 12–16 weeks). **High-Yield Clinical Pearls for NEET-PG:** * **Sequence of appearance (TVS):** Gestational Sac (5 wks) → Yolk Sac (5.5 wks) → Fetal Pole/Cardiac activity (6 wks). * **Discriminatory Zone:** The level of serum β-hCG at which a gestational sac should be visible. For TVS, this is typically **1,500–2,000 mIU/mL**. * **Yolk Sac:** The first structure visible *within* the gestational sac; its presence confirms an intrauterine pregnancy and rules out a pseudogestational sac.

Question 1

All of the following antenatal screening tools indicate increased risk of Down syndrome EXCEPT?

Accepted Answer

Decreased nuchal fold thickness

Answer

Increased Inhibin level

Answer

Absence of nasal bone

Answer

Decreased PAPP-A level

Question 2

A 37-year-old primigravida, Rh-negative patient at 16 weeks gestation is concerned about her pregnancy due to her age. She is HIV negative, hepatitis B surface antigen negative, Rubella nonimmune, and asymptomatic. Her triple test results are normal. Despite this, she insists on undergoing amniocentesis due to her age. What is the next best step in management?

Accepted Answer

Advise against amniocentesis as it could increase the risk of isoimmunization.

Answer

Carefully follow Rh antibody titers and administer Anti-D immunoglobulin if evidence of isoimmunization is present.

Answer

Administer Anti-D immunoglobulin at 28 weeks of gestation and after delivery if the baby is Rh-negative.

Answer

Administer Anti-D immunoglobulin prior to her amniocentesis.

Question 3

A 30-year-old G1P0 woman complains of nausea and vomiting for the first 3 months of her pregnancy. She is noted to have a hemoglobin level of 9.0 g/dl and a mean corpuscular volume of 110 fL (normal 90-105 fL). Which of the following is the most likely etiology of the anemia?

Accepted Answer

Folate deficiency

Answer

Iron deficiency

Answer

Vitamin B12 deficiency

Answer

Physiologic anemia of pregnancy

Question 4

Which of the following is NOT true about femur length used as a fetal biometric measure?

Accepted Answer

Femur length correlates well with both BPD and gestational age.

Answer

Femur length used for gestational age estimation has a variation of 7 to 11 days in the second trimester.

Answer

A shortened femur length suggests evaluation for skeletal dysplasia.

Answer

Femur length is measured excluding the epiphysis.

Question 5

Which clotting factor is not increased in pregnancy?

Accepted Answer

Factor 11

Answer

Factor 2

Answer

Factor 7

Answer

Factor 10

Question 6

At what gestational age is the following procedure ideally performed?

Accepted Answer

10-13 weeks

Answer

13-15 weeks

Answer

20-24 weeks

Answer

24 weeks onwards

Question 7

Which of the following statements is FALSE regarding chorionic villus sampling?

Accepted Answer

Strongly associated with faciomandibular defects

Answer

Performed between 10-12 weeks of gestation

Answer

Rh immunoglobulin prophylaxis is necessary for Rh-negative mothers

Answer

Performed to diagnose genetic disorders

Question 8

Which of the following changes that occur in the renal system during pregnancy is FALSE?

Accepted Answer

The kidneys become smaller compared to their pre-pregnant size.

Answer

The renal calyces and ureters show significant dilatation.

Answer

Pregnancy-induced changes are responsible for an increased risk of upper urinary tract infections.

Answer

There is an increased glomerular filtration rate.

Question 9

At what value for a one-hour glucose challenge test would you recommend a standard glucose tolerance test?

Accepted Answer

140 mg/dL

Answer

120 mg/dL

Answer

150 mg/dL

Answer

160 mg/dL

Question 10

Which of the following embryonic structures is the earliest ultrasonographically visible indicator of pregnancy?

Accepted Answer

Gestational sac

Answer

Fetal pole

Answer

Fetal heart activity

Answer

Fetal skeleton

Prenatal Care — MCQs

Prenatal Care — MCQs

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