Maternal-Fetal Medicine Practice Questions

Q: What is the most common site of ectopic pregnancy in the fallopian tube?

Ampulla. **Explanation:** Ectopic pregnancy occurs when a fertilized ovum implants outside the normal uterine cavity. The **Fallopian tube** is the most common site for ectopic pregnancy, accounting for approximately **95-97%** of all cases. **1. Why Ampulla is Correct:** The **Ampulla** is the widest and longest part of the fallopian tube, making it the most frequent site for fertilization. Consequently, it is the most common site for ectopic implantation, accounting for approximately **70-80%** of tubal pregnancies. **2. Analysis of Incorrect Options:** * **Infundibulum (approx. 5%):** This is the distal, funnel-shaped portion. Implantation here is less common and often results in tubal abortion. * **Isthmus (approx. 12%):** This is the narrow, muscular portion. While less common than the ampulla, pregnancies here are more likely to result in early rupture (usually by 6-8 weeks) due to the lack of distensibility. * **Interstitium (approx. 2-3%):** This is the segment within the uterine wall. Though the least common tubal site, it is the **most dangerous**. Because the area is highly vascular (near the uterine and ovarian artery anastomosis), rupture here occurs later (12-16 weeks) and can lead to massive, life-threatening hemorrhage. **High-Yield Clinical Pearls for NEET-PG:** * **Overall Most Common Site:** Ampulla of the Fallopian tube. * **Most Common Site for Rupture:** Isthmus (earliest rupture) vs. Interstitial (latest/most severe rupture). * **Classic Triad:** Amenorrhea, abdominal pain, and vaginal bleeding (present in only 50% of cases). * **Gold Standard Investigation:** Transvaginal Ultrasound (TVS) + Serum β-hCG (Correlation with the "Discriminatory Zone"). * **Arias-Stella Reaction:** Hypersecretory endometrium seen on biopsy, which is suggestive of pregnancy but not specific to ectopic.

Q: Which of the following is NOT a cause of acute abdomen in pregnancy?

Placenta previa. **Explanation:** The core concept in evaluating an acute abdomen in pregnancy is the presence of **pain**. An "acute abdomen" refers to a sudden, severe abdominal pain that may require urgent surgical or medical intervention. **Why Placenta Previa is the correct answer:** Placenta previa is classically characterized by **painless, causeless, and recurrent** vaginal bleeding in the second half of pregnancy. Because the bleeding occurs from the separation of the placenta from the lower uterine segment without uterine contractions or concealed hemorrhage, it does not typically cause abdominal pain or peritoneal irritation. Therefore, it is not a cause of acute abdomen. **Analysis of incorrect options:** * **Abortion:** Threatened or inevitable abortions are associated with uterine contractions and cervical dilation, leading to significant pelvic pain and cramping. * **Preterm Labor:** This involves regular, painful uterine contractions leading to cervical changes before 37 weeks, presenting as acute abdominal/pelvic pain. * **Appendicitis:** This is the most common non-obstetric surgical emergency during pregnancy. It presents with acute right-sided abdominal pain (though the location may shift upward as the uterus grows). **NEET-PG High-Yield Pearls:** * **Abruptio Placentae vs. Placenta Previa:** Abruption is **painful** (due to retroplacental hematoma and uterine hypertonicity), whereas Previa is **painless**. * **Diagnosis:** Transvaginal Ultrasound (TVS) is the gold standard for diagnosing Placenta Previa. **Digital vaginal examination is strictly contraindicated** (the "Double Setup" rule) until previa is ruled out, as it can provoke torrential hemorrhage. * **Most common cause of acute abdomen in pregnancy:** Appendicitis. * **Most common obstetric cause of acute abdomen:** Ectopic pregnancy (1st trimester) or Abruptio placentae (3rd trimester).

Q: Which of the following tests is done to differentiate between maternal and fetal blood in a case of fetomaternal hemorrhage?

Kleihauer Betke test. **Explanation:** The **Kleihauer-Betke (KB) test** is the gold standard for quantifying the extent of fetomaternal hemorrhage (FMH). It is based on the principle of **acid elution**. Fetal hemoglobin (HbF) is resistant to acid elution, whereas adult hemoglobin (HbA) is sensitive. When a maternal blood smear is treated with acid, HbA is leached out of the maternal red cells, leaving them as pale "ghost cells." The fetal red cells retain their hemoglobin and appear dark pink/red under the microscope. This allows for the calculation of the volume of fetal blood in maternal circulation, which is crucial for determining the required dose of Anti-D immunoglobulin. **Analysis of Incorrect Options:** * **Apt test:** This is used to differentiate fetal from maternal blood in cases of **neonatal hematemesis or melena** (e.g., swallowed maternal blood during delivery vs. GI bleed) or vaginal bleeding (Vasa Previa). It uses alkali (NaOH) denaturation. * **Bubbling test (Shake test):** A bedside test used to assess **fetal lung maturity** by checking for the presence of surfactant in amniotic fluid. * **Liley test:** Historically used to manage **Rh isoimmunization** by measuring bilirubin levels in amniotic fluid via spectrophotometry ($\Delta OD_{450}$) to assess the severity of fetal hemolysis. **High-Yield Clinical Pearls for NEET-PG:** * **KB Test Formula:** Volume of FMH (mL) = (Number of fetal cells / Total cells) × 5000 mL. * **Anti-D Dosing:** One 300 mcg dose of Anti-D covers up to **30 mL** of fetal whole blood (or 15 mL of fetal RBCs). * The **Rosette test** is a qualitative screening test for FMH; if positive, it must be followed by the KB test for quantification.

Q: A 25-year-old G2P1 female has a history of previous preterm birth at 32 weeks. What is the percentage chance of preterm birth in this pregnancy?

15%. **Explanation:** The single most significant risk factor for preterm birth (PTB) is a **prior history of spontaneous preterm birth**. The risk of recurrence increases significantly based on the number and timing of previous episodes. **1. Why 15% is correct:** Statistically, a woman with one previous preterm birth has a **15–17% risk** of recurrence in her subsequent pregnancy. This represents a nearly three-fold increase compared to the baseline risk in the general population (which is approximately 5–10%). If a woman has two prior preterm births, the risk escalates further to approximately 30–35%. **2. Analysis of Incorrect Options:** * **A (5%):** This represents the lower end of the baseline risk for a primigravida or a woman with a previous full-term delivery. * **B (10%):** This is the average global incidence of preterm birth but does not account for the significantly increased risk conferred by a prior history. * **D (25%):** This risk level is typically associated with women who have had **two** previous preterm births, rather than one. **High-Yield Clinical Pearls for NEET-PG:** * **Prophylaxis:** For patients with a history of spontaneous PTB, the standard of care is **17-alpha-hydroxyprogesterone caproate** (starting at 16–24 weeks) or vaginal progesterone. * **Cervical Screening:** Serial transvaginal ultrasound (TVUS) to measure **cervical length** is indicated. A length **<25 mm** before 24 weeks is a strong predictor of PTB. * **Golden Rule:** The earlier the gestational age of the previous preterm birth, the higher the risk of recurrence in the current pregnancy.

Q: What is the key difference between ectopic pregnancy and threatened abortion?

Uterine size corresponds to gestational age. In the context of early pregnancy complications, differentiating between ectopic pregnancy and threatened abortion is a high-yield clinical skill for NEET-PG. **Explanation of the Correct Answer:** In a **threatened abortion**, the pregnancy is intrauterine. Therefore, the **uterine size corresponds to the period of amenorrhea (gestational age)**. In contrast, in an **ectopic pregnancy**, the uterus is typically **smaller** than the period of amenorrhea because the gestational sac is located extra-uterinely (most commonly in the fallopian tube), and the uterus only undergoes minor decidual changes. **Analysis of Incorrect Options:** * **A. Presence of minimal vaginal bleeding:** Both conditions present with spotting or minimal bleeding. In ectopic pregnancy, bleeding is usually dark brown and scanty; in threatened abortion, it is fresh and bright red. * **B. Pain typically follows bleeding:** This is a classic feature of **threatened abortion** (Bleeding → Pain). In **ectopic pregnancy**, the sequence is reversed: **Pain precedes bleeding** (Pain → Bleeding). * **D. Manifests at an early gestational age:** Both conditions typically manifest in the first trimester (6–10 weeks), making this a poor differentiating factor. **NEET-PG High-Yield Pearls:** * **The Classic Triad of Ectopic Pregnancy:** Amenorrhea, abdominal pain, and vaginal bleeding. * **Arias-Stella Reaction:** Hypersecretory endometrium seen on histology in ectopic pregnancy (not pathognomonic, but highly suggestive). * **Discriminatory Zone:** If Serum β-hCG is >1500–2000 mIU/mL and the gestational sac is not visible on Transvaginal Ultrasound (TVS), suspect ectopic pregnancy. * **Cervical Os:** In both threatened abortion and ectopic pregnancy, the internal os remains **closed**.

Q: Which of the following methods of treating eclampsia has the least effect on neonates?

Magnesium sulfate regimen. **Explanation:** The management of eclampsia focuses on controlling seizures while minimizing maternal and neonatal morbidity. **Magnesium sulfate ($MgSO_4$)** is the gold standard (drug of choice) because it is highly effective at preventing recurrent seizures without causing significant central nervous system (CNS) depression in the neonate. 1. **Why Magnesium Sulfate is Correct:** Unlike sedatives, $MgSO_4$ acts primarily at the neuromuscular junction and as an NMDA receptor antagonist. While it does cross the placenta, at therapeutic maternal levels, it does not cause significant respiratory depression or sedation in the newborn. In fact, it provides a **neuroprotective effect** for preterm neonates, reducing the risk of cerebral palsy. 2. **Why Other Options are Incorrect:** * **Diazepam:** This benzodiazepine crosses the placenta rapidly and has a long half-life. It causes "Floppy Infant Syndrome," characterized by neonatal respiratory depression, hypotonia, and impaired thermoregulation. * **Phenobarbitone:** This barbiturate causes prolonged neonatal CNS depression, leading to poor sucking reflexes and respiratory distress. * **Lytic Cocktail:** This combination (usually Chlorpromazine, Promethazine, and Pethidine) causes profound maternal and neonatal sedation and is now considered obsolete in modern obstetric practice. **Clinical Pearls for NEET-PG:** * **Pritchard Regimen:** The standard IM regimen for $MgSO_4$ (4g IV + 10g IM loading; 5g IM every 4 hours). * **Therapeutic Range:** 4–7 mEq/L. * **Toxicity Signs:** Loss of patellar reflex (earliest sign at 7–10 mEq/L), followed by respiratory depression (>12 mEq/L). * **Antidote:** 10 ml of 10% Calcium Gluconate IV (administered slowly).

Question 1

Which scenario leads to the most severe Rh-isoimmunization in a fetus?

Accepted Answer

Rh negative mother and Rh positive fetus in the second pregnancy.

Answer

Rh positive mother and Rh negative fetus.

Answer

Rh positive mother and Rh negative fetus in the 15th pregnancy.

Answer

Rh positive mother and Rh positive fetus in the second pregnancy.

Question 2

Which of the following medications is the drug of choice for severe preeclampsia?

Accepted Answer

Labetalol

Answer

Metoprolol

Answer

Alpha-methyldopa

Answer

Nifedipine

Question 3

A 21-year-old female presents with painless vaginal bleeding at term. Her previous labor was normal. What is the next line of management?

Accepted Answer

Examination in the operating theatre followed by amniotomy

Answer

Lower segment cesarean section (LSCS)

Answer

Perineal examination in the emergency room

Answer

Hysterectomy

Question 4

What is the most common site of ectopic pregnancy in the fallopian tube?

Accepted Answer

Ampulla

Answer

Infundibulum

Answer

Isthmus

Answer

Interstitium

Question 5

Which of the following is NOT a cause of acute abdomen in pregnancy?

Accepted Answer

Placenta previa

Answer

Abortion

Answer

Preterm labor

Answer

Appendicitis

Question 6

Which of the following statements regarding epilepsy in pregnancy is true?

Accepted Answer

Folic acid supplementation helps prevent the risk of neural tube defects.

Answer

Sodium valproate is the drug of choice.

Answer

Therapeutic drug monitoring is not required.

Answer

Lamotrigine is the most teratogenic antiepileptic drug.

Question 7

Which of the following tests is done to differentiate between maternal and fetal blood in a case of fetomaternal hemorrhage?

Accepted Answer

Kleihauer Betke test

Answer

Apt test

Answer

Bubbling test

Answer

Liley test

Question 8

A 25-year-old G2P1 female has a history of previous preterm birth at 32 weeks. What is the percentage chance of preterm birth in this pregnancy?

Accepted Answer

15%

Answer

5%

Answer

10%

Answer

25%

Question 9

What is the key difference between ectopic pregnancy and threatened abortion?

Accepted Answer

Uterine size corresponds to gestational age

Answer

Presence of minimal vaginal bleeding

Answer

Pain typically follows bleeding

Answer

Manifests at an early gestational age

Question 10

Which of the following methods of treating eclampsia has the least effect on neonates?

Accepted Answer

Magnesium sulfate regimen

Answer

Lytic cocktail regimen

Answer

Diazepam therapy

Answer

Phenobarbitone therapy

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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