Maternal-Fetal Medicine Practice Questions

Q: A 25-year-old female, 5 months pregnant, presents for the first time without prior prenatal care. She is 168 cm tall, weighs 59 kg, and her blood pressure is 120/84 mm Hg. Fundal height is 17 cm, fetal movements are appreciated, and FHR is 140/min. Her past medical history is significant for hypertension, for which she takes enalapril. Dipstick results are negative. Which of the following tests should be performed?

Ultrasound of fetal kidneys. **Explanation:** The core issue in this clinical scenario is the use of **Enalapril**, an ACE inhibitor (ACEi), during pregnancy. ACE inhibitors are known teratogens, specifically categorized as FDA Category D. **1. Why Ultrasound of Fetal Kidneys is Correct:** ACE inhibitors interfere with the fetal renin-angiotensin-aldosterone system (RAAS), which is essential for normal fetal renal development and function. Exposure, particularly in the second and third trimesters, leads to **ACE inhibitor fetopathy**. This is characterized by fetal renal tubular dysgenesis, which results in **oligohydramnios** (due to decreased fetal urine production). This can further lead to pulmonary hypoplasia, limb contractures, and calvarial hypoplasia. Therefore, an ultrasound to assess fetal kidneys and amniotic fluid volume is the immediate priority. **2. Why Other Options are Incorrect:** * **A. Chorionic Villus Sampling (CVS):** CVS is typically performed between 10–13 weeks of gestation. At 5 months (approx. 20 weeks), it is too late for CVS. * **B. Group B Streptococcus (GBS) testing:** Screening for GBS is routinely performed between 36 0/7 and 37 6/7 weeks of gestation, not at 20 weeks. * **C. Triple test:** This screening for aneuploidies and neural tube defects is performed between 15–20 weeks. While the patient is in this window, the immediate risk posed by ACEi exposure (structural renal damage) takes precedence, and ultrasound is a better diagnostic tool for both anatomy and potential complications. **Clinical Pearls for NEET-PG:** * **ACEi/ARBs in Pregnancy:** Contraindicated. They cause renal agenesis, oligohydramnios, and "Potter-like" sequence. * **Antihypertensives of Choice:** Labetalol (1st line), Methyldopa, or Nifedipine. * **Critical Window:** While ACEi are most dangerous in the 2nd/3rd trimester for renal issues, 1st-trimester exposure is linked to cardiac and CNS malformations.

Q: What is the surest sign of intrauterine fetal death?

Gas in the aorta. **Explanation:** Intrauterine Fetal Death (IUFD) is diagnosed through various radiological and clinical signs. The **surest (most specific and earliest) sign** of fetal death is the presence of **gas in the fetal heart or great vessels (Aorta)**, known as **Robert’s Sign**. 1. **Why "Gas in the Aorta" is correct:** Robert’s Sign occurs due to the release of gases (mainly nitrogen) from the decomposition of fetal blood. It can appear on an X-ray or ultrasound as early as **6 to 12 hours** after death. Because gas cannot exist within the circulatory system of a living fetus, its presence is a pathognomonic and definitive indicator of fetal demise. 2. **Analysis of Incorrect Options:** * **Small sized fetus:** This is non-specific. A small fetus may indicate Intrauterine Growth Restriction (IUGR) or incorrect dating rather than death. * **Overriding of cranial bones (Spalding’s Sign):** While a classic sign, it is **not the surest**. It occurs due to the liquefaction of the brain and loss of intracranial pressure, causing the vault bones to collapse. Crucially, it takes **4 to 7 days** to develop and can be a false positive in a living fetus during labor (due to molding). * **Spalding's Sign:** (See above). It is a late sign compared to Robert's Sign. **High-Yield Clinical Pearls for NEET-PG:** * **Robert’s Sign:** Gas in fetal vessels (Earliest sign, ~12 hours). * **Spalding’s Sign:** Overriding of skull bones (Late sign, >4 days). * **Deuel’s Halo Sign:** Edema of the fetal scalp causing a "halo" appearance (due to fluid accumulation in subcutaneous tissues). * **Curvature of the Spine:** Excessive angulation of the fetal spine due to loss of muscle tone. * **Gold Standard:** The investigation of choice for IUFD today is **Ultrasonography**, demonstrating the absence of fetal cardiac activity.

Q: What is the most common cause of thrombocytopenia in pregnancy?

Benign gestational thrombocytopenia. **Explanation:** **Gestational Thrombocytopenia** (also known as incidental thrombocytopenia of pregnancy) is the most common cause of a low platelet count during pregnancy, accounting for approximately **70–80% of cases**. It is a diagnosis of exclusion characterized by a mild decrease in platelets (typically >70,000/µL, but most often >100,000/µL) occurring in the mid-to-late second or third trimester. The underlying mechanism is thought to be a combination of hemodilution (increased plasma volume) and accelerated platelet consumption in the placenta. It is "benign" because it does not affect the fetus (no fetal thrombocytopenia) and resolves spontaneously within 1–2 months postpartum. **Analysis of Incorrect Options:** * **Option A & C (Immune/Idiopathic Thrombocytopenia):** ITP is the most common cause of isolated thrombocytopenia in the **first trimester**. Unlike gestational thrombocytopenia, ITP can cause severe thrombocytopenia (<50,000/µL) and carries a risk of neonatal thrombocytopenia as IgG antibodies can cross the placenta. * **Option B (Incidental Thrombocytopenia):** While this is a synonym for gestational thrombocytopenia, "Benign Gestational Thrombocytopenia" is the more specific clinical terminology used in standard textbooks (like Williams Obstetrics) to describe this physiological variant. **NEET-PG High-Yield Pearls:** * **Platelet Cut-off:** Gestational thrombocytopenia rarely drops below 70,000/µL. If platelets are 70,000–80,000/µL. * **Second most common cause:** Preeclampsia/HELLP syndrome (approx. 20% of cases).

Q: All are true regarding symmetric IUGR except?

Obstetric cause like utero-placental insufficiency. **Explanation:** Intrauterine Growth Restriction (IUGR) is classified into two types: **Symmetric (Type I)** and **Asymmetric (Type II)**. Understanding the distinction is high-yield for NEET-PG. **Why Option A is the correct answer (The False Statement):** Symmetric IUGR is typically caused by **intrinsic factors** that affect the fetus from early pregnancy, such as chromosomal abnormalities (e.g., Trisomies), intrauterine infections (TORCH), or severe maternal malnutrition. In contrast, **utero-placental insufficiency** is the hallmark cause of **Asymmetric IUGR**, where growth slows down later in pregnancy (third trimester) due to a lack of nutrients. **Analysis of other options:** * **Option B (Ponderal Index > 2):** In symmetric IUGR, both weight and length are proportionately reduced. Therefore, the Ponderal Index (Weight/Length³) remains **normal (>2)**. In asymmetric IUGR, the fetus is "wasted," leading to a low Ponderal Index (<2). * **Option C (First Trimester):** Symmetric IUGR results from an insult during the **hyperplastic phase** of cellular growth (early pregnancy), leading to a decrease in the total number of cells. * **Option D (Brain growth spared):** This is a characteristic of **Asymmetric IUGR** (Brain-sparing effect). In **Symmetric IUGR**, there is no brain-sparing; the head circumference, abdominal circumference, and femur length are all proportionately small. **Clinical Pearls for NEET-PG:** * **Symmetric IUGR:** Early onset, decreased cell *number*, normal HC/AC ratio, Ponderal Index >2, poor prognosis. * **Asymmetric IUGR:** Late onset (3rd trimester), decreased cell *size*, increased HC/AC ratio (Head > Abdomen), Ponderal Index <2, better prognosis with postnatal catch-up growth. * **Most common cause of IUGR overall:** Utero-placental insufficiency (Asymmetric).

Q: Fetal blood loss in abnormal cord insertion is seen in which of the following conditions?

Vasa previa. **Explanation:** **Vasa previa** is the correct answer because it involves fetal vessels running through the membranes, unprotected by placental tissue or the umbilical cord (Wharton’s jelly), across the internal os. This condition is most commonly associated with **velamentous insertion of the cord** or a **succenturiate lobe**. When the membranes rupture (spontaneously or artificially), these exposed fetal vessels are easily lacerated, leading to rapid fetal exsanguination. Since the blood lost is entirely fetal, even a small amount can lead to fetal distress and death. **Incorrect Options:** * **Decidua basalis:** This is the maternal component of the placenta. Bleeding here is maternal in origin, typically seen in placental abruption. * **Battledore placenta (Marginal insertion):** The cord inserts at the margin of the placenta rather than the center. While it increases the risk of preterm labor, it rarely causes fetal vessel rupture or significant fetal blood loss. * **Succenturiate placenta:** This refers to an accessory lobe. While it is a *risk factor* for vasa previa (if the connecting vessels cross the os), the presence of the lobe itself does not imply fetal blood loss unless vasa previa is concurrently present. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Rupture of membranes + Painless vaginal bleeding + Fetal bradycardia/distress. * **Diagnosis:** Antenatally via **Transvaginal Color Doppler** (Gold Standard). * **Apt Test / Ogita Test:** Used to differentiate fetal hemoglobin from maternal hemoglobin in vaginal blood. * **Management:** If diagnosed prenatally, elective Cesarean section is planned at 34–35 weeks to avoid labor and membrane rupture.

Q: What is the dose of Anti-D immunoglobulin given to an Rh-negative patient with ectopic pregnancy in the first trimester?

50mcg. **Explanation:** The correct answer is **50 mcg (Option D)**. Rh-isoimmunization occurs when an Rh-negative mother is exposed to Rh-positive fetal red blood cells, leading to the production of anti-D antibodies. In the first trimester (up to 12–13 weeks), the total fetal blood volume is very small. Therefore, a "mini-dose" of **50 mcg** of Anti-D immunoglobulin is sufficient to neutralize the potential feto-maternal hemorrhage (FMH) associated with conditions like ectopic pregnancy, threatened abortion, or induced abortion. **Analysis of Options:** * **10 mcg, 25 mcg, 40 mcg (Options A, B, C):** These doses are sub-therapeutic and do not follow standard clinical guidelines (ACOG/RCOG/FOGSI) for the prevention of Rh-sensitization. * **50 mcg (Option D):** This is the standard "mini-dose" recommended for first-trimester sensitizing events. It can neutralize up to 2.5–5 ml of Rh-positive whole blood. **High-Yield Clinical Pearls for NEET-PG:** * **Standard Dose:** After 12 weeks of gestation or following full-term delivery, the standard dose is **300 mcg**, which neutralizes **30 ml** of fetal whole blood (or 15 ml of packed RBCs). * **Timing:** Anti-D should ideally be administered within **72 hours** of the sensitizing event. * **Kleihauer-Betke (KB) Test:** Used to quantify the volume of FMH to determine if additional doses of Anti-D are required beyond the standard 300 mcg in the third trimester or postpartum. * **Routine Prophylaxis:** In an unsensitized Rh-negative woman, 300 mcg is routinely given at **28 weeks** of gestation.

Q: Antenatal corticosteroids to reduce neonatal respiratory distress syndrome is most effective:

When given between 28 and 34 weeks of gestation. **Explanation:** The primary goal of antenatal corticosteroids (ACS) is to accelerate fetal lung maturity by stimulating the production of surfactant by Type II pneumocytes. **Why Option A is correct:** The maximum benefit of ACS in reducing the incidence and severity of Respiratory Distress Syndrome (RDS), Intraventricular Hemorrhage (IVH), and Necrotizing Enterocolitis (NEC) is seen when administered between **24 and 34 weeks** of gestation. While the question specifies 28–34 weeks, this remains the most effective window as the fetal lungs are in the saccular stage of development and highly responsive to steroids. **Why other options are incorrect:** * **Option B:** Weekly administration (serial courses) is contraindicated. It does not provide additional respiratory benefit and is associated with decreased birth weight and reduced head circumference. * **Option C:** While the maximum effect occurs if delivery happens between 24 hours and 7 days after the first dose, "within 48 hours" is too narrow a window. The treatment is most effective when the full course is completed at least 24 hours before delivery. * **Option D:** Before 24–26 weeks (pre-viable or periviable period), the lungs are in the canalicular stage with minimal surfactant-producing capacity, making steroids less effective, though they are still considered from 23 weeks in certain guidelines. **NEET-PG High-Yield Pearls:** * **Standard Regimen:** Betamethasone (12 mg IM, 2 doses, 24 hours apart) or Dexamethasone (6 mg IM, 4 doses, 12 hours apart). * **Betamethasone** is generally preferred due to better reduction in IVH. * **Rescue Dose:** A single repeat course can be given if the initial course was >7 days ago and the gestational age is <34 weeks. * **Late Preterm:** Recent guidelines (ACOG) now suggest considering ACS up to **36 weeks 6 days** in women at high risk of imminent preterm birth who have not received a prior course.

Question 1

Which of the following is NOT a serious complication of pregnancy with heart disease?

Accepted Answer

Antepartum hemorrhage

Answer

Postpartum hemorrhage

Answer

Puerperal infection

Answer

Puerperal thromboembolism

Question 2

Regarding intrauterine growth restriction (IUGR), which of the following statements is correct?

Accepted Answer

Abdominal circumference is the most accurate measurement for assessing IUGR.

Answer

Abdominal circumference (AC) is the least sensitive parameter for detection of IUGR.

Answer

In asymmetric IUGR, the head circumference/abdominal circumference (HC/AC) ratio is reduced.

Answer

Serial biparietal diameter (BPD) is the only important measurement in IUGR.

Question 3

Which of the following statements regarding twin pregnancy is false?

Accepted Answer

The most common type of dizygotic twins occurs through superfecundation.

Answer

The frequency of monozygotic twins is 1 in 250 pregnancies.

Answer

Division after the formation of the embryonic disk results in conjoined twins.

Answer

A dichorionic twin pregnancy can also denote monozygotic twins.

Question 4

A 25-year-old female, 5 months pregnant, presents for the first time without prior prenatal care. She is 168 cm tall, weighs 59 kg, and her blood pressure is 120/84 mm Hg. Fundal height is 17 cm, fetal movements are appreciated, and FHR is 140/min. Her past medical history is significant for hypertension, for which she takes enalapril. Dipstick results are negative. Which of the following tests should be performed?

Accepted Answer

Ultrasound of fetal kidneys

Answer

Chorionic Villus Sampling (CVS)

Answer

Group B Streptococcus testing

Answer

Triple test

Question 5

What is the surest sign of intrauterine fetal death?

Accepted Answer

Gas in the aorta

Answer

Small sized fetus

Answer

Overriding of cranial bones

Answer

Spalding's sign

Question 6

What is the most common cause of thrombocytopenia in pregnancy?

Accepted Answer

Benign gestational thrombocytopenia

Answer

Immune thrombocytopenia

Answer

Incidental thrombocytopenia

Answer

Idiopathic thrombocytopenia

Question 7

All are true regarding symmetric IUGR except?

Accepted Answer

Obstetric cause like utero-placental insufficiency

Answer

Ponderal index > 2

Answer

Problem occurring in first trimester

Answer

Brain growth (head circumference) spared

Question 8

Fetal blood loss in abnormal cord insertion is seen in which of the following conditions?

Accepted Answer

Vasa previa

Answer

Decidua basalis

Answer

Battledore placenta

Answer

Succenturiate placenta

Question 9

What is the dose of Anti-D immunoglobulin given to an Rh-negative patient with ectopic pregnancy in the first trimester?

Accepted Answer

50mcg

Answer

10mcg

Answer

25mcg

Answer

40mcg

Question 10

Antenatal corticosteroids to reduce neonatal respiratory distress syndrome is most effective:

Accepted Answer

When given between 28 and 34 weeks of gestation

Answer

When given every week

Answer

When given within 48 hours of delivery

Answer

When given less than 28 weeks of gestation

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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