Maternal-Fetal Medicine Practice Questions

Q: What is the dose of anti-D gamma globulin given after term delivery for an Rh-negative mother and Rh-positive baby?

300 micrograms. **Explanation:** The administration of Anti-D gamma globulin (RhoGAM) is a critical intervention to prevent **Rh isoimmunization** in Rh-negative mothers. When an Rh-negative mother is exposed to Rh-positive fetal red blood cells (fetal-maternal hemorrhage), she develops antibodies that can cause Hemolytic Disease of the Fetus and Newborn (HDFN) in subsequent pregnancies. **Why 300 micrograms is correct:** The standard dose after a term delivery is **300 micrograms (1500 IU)**, administered intramuscularly within 72 hours. This dose is specifically calculated to neutralize up to **30 mL of Rh-positive whole blood** (or 15 mL of packed red cells). Since most term deliveries involve a feto-maternal hemorrhage of less than 30 mL, this dose is sufficient for routine prophylaxis. **Analysis of Incorrect Options:** * **50 micrograms:** This "mini-dose" is used only for first-trimester events (up to 12 weeks gestation), such as spontaneous abortion or ectopic pregnancy, where fetal blood volume is minimal. * **100 & 200 micrograms:** These are sub-therapeutic doses for term deliveries and do not follow standard international or national (FOGSI/ACOG) guidelines for post-exposure prophylaxis. **High-Yield Clinical Pearls for NEET-PG:** * **Kleihauer-Betke (KB) Test:** Used to quantify the volume of fetal-maternal hemorrhage. If the hemorrhage exceeds 30 mL, additional doses of Anti-D are required. * **Antenatal Prophylaxis:** A routine dose of 300 mcg is also given at **28 weeks** of gestation to all Rh-negative unsensitized mothers. * **Indirect Coombs Test (ICT):** Must be negative in the mother before administration (indicates she is not yet sensitized). * **Route:** Intramuscular (IM) is standard; however, intravenous (IV) preparations exist for specific scenarios.

Q: Which fetal abnormality is commonly associated with maternal diabetes mellitus?

Sacral agenesis. **Explanation:** **Sacral agenesis** (also known as Caudal Regression Syndrome) is the most specific fetal malformation associated with maternal diabetes mellitus. While the absolute incidence is low, a child born with sacral agenesis is over 200 times more likely to have a mother with diabetes compared to the general population. This condition involves the incomplete development of the lower spine and is thought to result from hyperglycemia-induced oxidative stress during the first trimester (organogenesis). **Analysis of Incorrect Options:** * **B. Hydrocephalus:** While CNS anomalies (like neural tube defects) are more common in diabetic pregnancies, hydrocephalus is not as pathognomonic or specifically linked to diabetes as sacral agenesis. * **C. Respiratory Distress Syndrome (RDS):** This is a common **neonatal** complication of maternal diabetes (due to hyperinsulinemia inhibiting surfactant production), but it is a functional/maturational issue rather than a structural **fetal abnormality** or malformation. * **D. Phocomelia:** This is the hallmark malformation associated with maternal **Thalidomide** intake, characterized by the absence of long bones in the limbs. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Malformation:** Congenital Heart Defects (specifically **Ventricular Septal Defect**). * **Most Specific Malformation:** Sacral Agenesis/Caudal Regression Syndrome. * **Cardiac-specific:** Transposition of the Great Arteries (TGA) and Hypertrophic Cardiomyopathy (asymmetric septal hypertrophy) are also highly associated. * **Screening:** HbA1c levels >8.5% in the first trimester significantly increase the risk of these structural anomalies.

Q: The classic triad of ruptured ectopic pregnancy includes all EXCEPT?

Fainting. The classic clinical triad of ectopic pregnancy is a high-yield concept for NEET-PG. Understanding the difference between the "classic triad" and "symptoms of rupture" is key to answering this question correctly. ### **Explanation** The **classic triad** of ectopic pregnancy consists of: 1. **Abdominal pain:** The most common symptom (95–100%), usually localized to the iliac fossa. 2. **Amenorrhea:** A history of a missed period (75–90%), typically 6–8 weeks prior. 3. **Vaginal bleeding:** Usually slight, dark brown "spotting" (70%), occurring after the onset of pain. **Fainting (Option A)** is the correct answer because it is **not** part of the classic triad. While fainting or syncope occurs in ruptured ectopic pregnancy due to intraperitoneal hemorrhage and hypovolemic shock, it is considered a **sign of rupture/complication** rather than a component of the primary diagnostic triad. ### **Analysis of Incorrect Options** * **Abdominal Pain (Option B):** The primary presenting symptom caused by tubal distension or peritoneal irritation. * **History of Amenorrhea (Option C):** Essential for the suspicion of any pregnancy-related pathology. * **Vaginal Bleeding (Option D):** Caused by the shedding of the decidua due to falling progesterone levels; it is a core component of the triad. ### **Clinical Pearls for NEET-PG** * **Gold Standard Investigation:** Transvaginal Ultrasound (TVS) + Serum β-hCG. * **Discriminatory Zone:** The β-hCG level (usually 1500–2000 mIU/mL) at which a gestational sac should be visible on TVS. * **Arias-Stella Reaction:** Hypersecretory endometrium seen on curettage, characteristic of (but not pathognomonic for) ectopic pregnancy. * **Most Common Site:** Ampulla of the Fallopian tube. * **Most Common Site of Rupture:** Isthmus (occurs early, around 6–8 weeks).

Q: What is the management of choice for placenta previa at 32 weeks gestation?

Conservative treatment. **Explanation:** The primary goal in managing placenta previa before term (less than 37 weeks) is to prolong the pregnancy to allow for fetal lung maturity, provided there is no active, life-threatening hemorrhage. This approach is known as **MacAfee’s Conservative Management**. **Why Conservative Treatment is Correct:** At 32 weeks, the fetus is preterm. If the maternal and fetal conditions are stable (bleeding is not profuse), the patient is managed with bed rest, corticosteroids (for lung maturity), and close monitoring. This reduces the risks associated with prematurity while keeping the patient in a facility equipped for an emergency Cesarean section if bleeding recurs. **Why Other Options are Incorrect:** * **Oxytocin & Ergometrine:** These are uterotonic agents. Oxytocin is used for induction of labor or postpartum hemorrhage (PPH) management, and Ergometrine is strictly for PPH. Using them in placenta previa before delivery is contraindicated as they cause uterine contractions, which can lead to massive placental separation and fatal hemorrhage. * **Per Vaginal (PV) Examination:** This is **strictly contraindicated** in suspected placenta previa. A digital exam can dislodge a clot or tear the placenta, leading to torrential, life-threatening bleeding. PV exams should only be performed in a "Double Setup" (in an OT ready for immediate surgery). **High-Yield Clinical Pearls for NEET-PG:** * **MacAfee’s Criteria:** Pregnancy <37 weeks, bleeding is not active/profuse, and the mother/fetus are stable. * **Investigation of Choice:** Transvaginal Ultrasound (TVS) is the gold standard (safe and more accurate than transabdominal). * **Delivery Timing:** In stable cases of placenta previa, elective delivery is usually planned at **36–37 weeks**. * **Stallworthy’s Sign:** A drop in fetal heart rate when the head is pressed into the pelvis (seen in posterior placenta previa).

Q: The lecithin/sphingomyelin (L/S) ratio is measured for assessing maturity of which organ?

Lung. **Explanation:** The **Lecithin/Sphingomyelin (L/S) ratio** is the gold standard biochemical test for assessing **fetal lung maturity**. **1. Why Lung is Correct:** Lecithin (Dipalmitoylphosphatidylcholine) is a major component of **surfactant**, which reduces surface tension in the alveoli to prevent collapse during expiration. While Sphingomyelin levels remain relatively constant throughout pregnancy, Lecithin production increases significantly after 32–34 weeks of gestation. * An **L/S ratio > 2:1** typically indicates mature lungs and a low risk of Respiratory Distress Syndrome (RDS). * An **L/S ratio < 1.5:1** indicates a high risk of RDS. **2. Why Other Options are Incorrect:** * **Brain, Heart, and Spleen:** While these organs undergo functional maturation during gestation, their maturity is not assessed via phospholipid concentrations in the amniotic fluid. Brain maturity is often clinically inferred by gestational age or neurological reflexes post-delivery, rather than biochemical markers. **3. NEET-PG High-Yield Pearls:** * **Diabetes Mellitus:** In pregnancies complicated by maternal diabetes, an L/S ratio of 2:1 may still result in RDS due to delayed functional maturity (interference by high insulin). In these cases, a ratio of **3:1** or the presence of **Phosphatidylglycerol (PG)** is a more reliable indicator. * **Phosphatidylglycerol (PG):** Its presence in amniotic fluid (appearing around 35 weeks) is the most reliable marker that RDS will not occur. * **Amniotic Fluid Sample:** The sample is obtained via **amniocentesis**. Contamination with blood or meconium can falsely alter the results. * **Shake Test (Bubble Stability Test):** A rapid bedside screening test for lung maturity; if bubbles form after shaking with ethanol, surfactant is present.

Question 1

A 19-year-old woman, gravida 2, para 0, abortion 1, is at 30 weeks gestation. Her fundal height measures 25cm. An obstetrical ultrasound examination reveals a 4-quadrant amniotic fluid index (AFI) of 4cm. Which of the following fetal conditions is associated with this finding?

Accepted Answer

Renal agenesis

Answer

Duodenal atresia

Answer

Open spina bifida

Answer

Tracheoesophageal fistula

Question 2

What is the dose of anti-D gamma globulin given after term delivery for an Rh-negative mother and Rh-positive baby?

Accepted Answer

300 micrograms

Answer

50 micrograms

Answer

200 micrograms

Answer

100 micrograms

Question 3

Which of the following is a non-invasive test used to diagnose fetal Rh genotype in Rh D alloimmunization?

Accepted Answer

Cell-free fetal DNA analysis

Answer

Chorionic villus sampling

Answer

Amniocentesis

Answer

Middle cerebral artery peak systolic velocity

Question 4

Which of the following statements is true?

Accepted Answer

Phosphatidyl glycerol in amniotic fluid is 100% confirmatory of lung maturity.

Answer

Glyburide is absolutely contraindicated for GDM.

Answer

Patients with GDM/DM should be delivered between 34 and 36 weeks of gestation due to the risk of sudden IUFD at full term.

Answer

PTH crosses the placenta.

Question 5

Which fetal abnormality is commonly associated with maternal diabetes mellitus?

Accepted Answer

Sacral agenesis

Answer

Hydrocephalus

Answer

Respiratory distress syndrome

Answer

Phocomelia

Question 6

What is the treatment for acute hydramnios with respiratory depression?

Accepted Answer

Amniocentesis

Answer

Termination of pregnancy

Answer

Diuretics

Answer

Sedation

Question 7

The classic triad of ruptured ectopic pregnancy includes all EXCEPT?

Accepted Answer

Fainting

Answer

Abdominal pain

Answer

History of amenorrhea

Answer

Vaginal bleeding

Question 8

What is the management of choice for placenta previa at 32 weeks gestation?

Accepted Answer

Conservative treatment

Answer

Oxytocin infusion

Answer

Ergometrine intravenous

Answer

Per vaginal examination and artificial rupture of membranes (ARM)

Question 9

The lecithin/sphingomyelin (L/S) ratio is measured for assessing maturity of which organ?

Accepted Answer

Lung

Answer

Brain

Answer

Heart

Answer

Spleen

Question 10

The KleihauerBetke test is used to detect:

Accepted Answer

Fetomaternal blood leak

Answer

Ferning pattern in the follicular phase

Answer

Cephalopelvic disproportion

Answer

Sperm-cervical mucus interaction

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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