Maternal-Fetal Medicine Practice Questions

Q: What is the dose of anti-D immunoglobulin to be given to non-immune Rh D negative women after delivery?

300 mcg. **Explanation:** The primary goal of administering Anti-D immunoglobulin (RhIg) is to prevent Rh isoimmunization in Rh-negative, non-sensitized women. The standard postpartum dose is **300 mcg (1500 IU)**, which is the correct answer (**Option C**). **Why 300 mcg?** This dose is specifically calculated to neutralize up to **15 mL of fetal red blood cells** (or 30 mL of whole fetal blood). Statistically, more than 99% of deliveries involve a feto-maternal hemorrhage (FMH) of less than 15 mL of fetal RBCs. Therefore, 300 mcg provides adequate coverage for the vast majority of standard deliveries. It should be administered intramuscularly within **72 hours** of delivery if the neonate is Rh-positive. **Analysis of Incorrect Options:** * **Option A (50 mcg):** This is a "mini-dose" used only for first-trimester events (up to 12–13 weeks), such as spontaneous or induced abortion, as the fetal blood volume is very small at this stage. * **Option B (150 mcg):** While used in some international protocols (like in the UK for certain indications), it is not the standard postpartum dose in the Indian or US (ACOG) guidelines for full-term delivery. * **Option D (450 mcg):** There is no standard single-vial dose of 450 mcg. If a Kleihauer-Betke test indicates an FMH greater than 15 mL of RBCs, additional doses of 300 mcg are added cumulatively. **High-Yield Clinical Pearls for NEET-PG:** * **Routine Antenatal Prophylaxis:** A 300 mcg dose is also given at **28 weeks** of gestation to all non-sensitized Rh-negative women. * **The 72-Hour Rule:** While 72 hours is the ideal window, if missed, Anti-D should still be given as soon as possible, up to **13–28 days** postpartum. * **Kleihauer-Betke (KB) Test:** Used to quantify the volume of FMH to determine if more than 300 mcg is required. * **Route:** Always Intramuscular (IM). If the patient has severe thrombocytopenia, it can be given subcutaneously.

Q: After 20 weeks of gestation, what is the main contribution to amniotic fluid?

Fetal urine. **Explanation:** The volume and composition of amniotic fluid change dynamically throughout pregnancy. After **20 weeks of gestation**, the primary source of amniotic fluid is **fetal urine**. **1. Why Fetal Urine is Correct:** By the second trimester (starting around 12 weeks and becoming dominant by 20 weeks), the fetal kidneys are functional. The fetus swallows amniotic fluid, which is absorbed by the gastrointestinal tract and then excreted as urine back into the amniotic sac. At term, a fetus produces approximately 700–1000 mL of urine per day. This recycling process is crucial for maintaining fluid volume and lung development. **2. Why Other Options are Incorrect:** * **Maternal serum (B):** While maternal serum contributes to fluid volume in the *first* trimester via the amnion, its role becomes negligible in the second half of pregnancy. * **Transudate through fetal skin (C):** This is the main source *before* 20 weeks. However, after 20 weeks, the fetal skin undergoes **keratinization**, making it impermeable to water and solutes. * **Transudate across the umbilical cord (D):** This (along with the chorionic plate) provides a minor contribution via the intramembranous pathway but is never the "main" source. **High-Yield Clinical Pearls for NEET-PG:** * **Renal Agenesis (Potter’s Syndrome):** Absence of kidneys leads to severe **oligohydramnios** because urine production is the main fluid source. * **Esophageal Atresia:** Inability of the fetus to swallow fluid leads to **polyhydramnios**. * **Peak Volume:** Amniotic fluid volume peaks at approximately **800 mL at 34 weeks** of gestation before gradually decreasing. * **Amniotic Fluid Index (AFI):** Normal range is 5–24 cm; 24 cm is polyhydramnios.

Q: Hydramnios is complicated by which of the following conditions, EXCEPT?

Post-dated pregnancy. **Explanation:** Hydramnios (Polyhydramnios) is defined as an amniotic fluid index (AFI) > 25 cm or a single deepest pocket (SDP) > 8 cm. It is associated with several maternal and fetal complications due to uterine overdistension. **Why Post-dated pregnancy is the correct answer:** Post-dated pregnancy (prolonged pregnancy) is typically associated with **Oligohydramnios**, not hydramnios. As the pregnancy progresses beyond 40 weeks, placental function declines (placental insufficiency), leading to decreased fetal renal perfusion and reduced fetal urine output, which is the primary source of amniotic fluid in late pregnancy. **Analysis of incorrect options:** * **Placenta Abruptio:** Sudden decompression of the overdistended uterus (e.g., during rupture of membranes) can lead to a shearing effect on the placenta, causing premature separation. * **Pre-eclampsia:** There is a known clinical association between hydramnios and pre-eclampsia (seen in ~25% of cases), likely due to increased uterine tension and placental factors. * **Atonic Hemorrhage:** Overdistension of the uterine muscle fibers by excessive fluid leads to poor uterine contractility (inertia) after delivery, making atonic Postpartum Hemorrhage (PPH) a major risk. **Clinical Pearls for NEET-PG:** * **Most common cause:** Idiopathic (approx. 50-60%). * **Most common fetal anomaly:** Anencephaly (due to lack of swallowing reflex and transudation from exposed meninges). * **Maternal association:** Diabetes mellitus is the most common maternal cause. * **Management:** Therapeutic amniocentesis is indicated if the mother is symptomatic (dyspnea/distress); Indomethacin can be used (before 32 weeks) to decrease fetal urine output.

Q: Abruptio placentae occurs in all except?

Alcoholics. **Explanation:** Abruptio placentae refers to the premature separation of a normally situated placenta from the uterine wall before the birth of the fetus. The etiology is primarily related to vascular compromise or direct trauma. **Why Alcoholics is the correct answer:** While chronic alcohol consumption is associated with Fetal Alcohol Syndrome and intrauterine growth restriction (IUGR), it is **not** a recognized independent risk factor for placental abruption. In contrast, substances like cocaine (a potent vasoconstrictor) are strongly linked to abruption. **Analysis of incorrect options:** * **Smokers:** Smoking causes decidual necrosis and placental hypoperfusion due to the vasoconstrictive effects of nicotine and increased carbon monoxide levels. This doubles the risk of abruption. * **Pregnancy-induced hypertension (PIH):** This is the **most common predisposing factor** for abruption. Chronic hypertension or preeclampsia leads to degenerative changes in the spiral arteries, causing retroplacental hemorrhage. * **Folic acid deficiency:** Deficiency leads to hyperhomocysteinemia, which causes endothelial damage and vascular thrombosis in the placental bed, predisposing the patient to premature separation. **Clinical Pearls for NEET-PG:** * **Most common cause:** Maternal hypertension (PIH/Chronic). * **Most common cause of DIC in pregnancy:** Abruptio placentae. * **Classic presentation:** Painful vaginal bleeding (revealed), uterine tenderness, and increased uterine tone (woody hard uterus). * **Couvelaire Uterus:** A complication where blood extravasates into the myometrium, seen during C-section as a purplish/bluish discoloration. * **Other risk factors:** Sudden uterine decompression (e.g., rupture of membranes in polyhydramnios), trauma, and short umbilical cord.

Q: Magnesium sulphate toxicity includes all of the following EXCEPT?

Oliguria. Magnesium sulphate ($MgSO_4$) is the drug of choice for seizure prophylaxis in pre-eclampsia and control in eclampsia [1]. It acts as a CNS depressant and neuromuscular blocker. The key to understanding its toxicity lies in the **sequential disappearance of physiological functions** as serum magnesium levels rise. ### Why Oliguria is the Correct Answer **Oliguria is a contraindication to/risk factor for toxicity, not a sign of toxicity itself.** $MgSO_4$ is excreted almost exclusively by the kidneys. If a patient has oliguria (urine output <30 ml/hr), the drug accumulates rapidly, leading to toxic levels [1]. Therefore, monitoring urine output is mandatory *during* administration to prevent toxicity, but the toxicity itself does not cause decreased urine output. ### Explanation of Incorrect Options (Signs of Toxicity) As serum levels increase (Normal therapeutic range: 4–7 mEq/L), toxicity manifests in this specific order: * **Loss of Patellar Reflex (8–10 mEq/L):** This is the **earliest clinical sign** of toxicity [1]. The knee-jerk reflex disappears due to the blockade of neuromuscular transmission [2]. * **Respiratory Depression (12–15 mEq/L):** Higher levels lead to paralysis of respiratory muscles [1]. * **Cardiac Arrest (>25 mEq/L):** Extreme levels cause direct myocardial depression and cardiac standstill [1]. ### High-Yield Clinical Pearls for NEET-PG * **Monitoring Parameters:** Always check for (1) Presence of patellar reflex, (2) Respiratory rate >12/min, and (3) Urine output >30 ml/hr (or 100 ml/4 hrs) [1]. * **Antidote:** 10 ml of **10% Calcium Gluconate** IV (administered slowly over 10 minutes) [1]. * **Therapeutic Level:** 4–7 mEq/L (or 4.8–8.4 mg/dL). * **Pritchard Regimen:** Total loading dose is 14g (4g IV + 10g IM). Maintenance is 5g IM every 4 hours in alternating buttocks.

Q: Which of the following statements regarding ectopic pregnancy is true?

Serum progesterone >25 ng/ml excludes ectopic pregnancy.. ### Explanation **1. Why Option A is Correct:** Serum progesterone is a highly reliable marker for assessing pregnancy viability, though it cannot pinpoint the location. A value **>25 ng/ml** is strongly associated with a healthy, viable intrauterine pregnancy (IUP), effectively excluding ectopic pregnancy with a sensitivity of approximately 97%. Conversely, values **<5 ng/ml** are highly suggestive of a non-viable pregnancy (either an ectopic or a failing IUP). **2. Why Other Options are Incorrect:** * **Options B & C:** These refer to the **Discriminatory Zone**—the level of β-hCG at which an intrauterine gestational sac should be visible via ultrasound. For Transvaginal Sonography (TVS), this threshold is typically **1500–2000 mIU/ml** (some protocols use 3500 mIU/ml to avoid false positives). Levels of 1000 mIU/ml are generally too low for reliable detection by TVS. * **Option D:** Methotrexate (a folate antagonist) is the **medical management of choice** for hemodynamically stable patients with unruptured ectopic pregnancies who meet specific criteria (e.g., β-hCG <5000 mIU/ml, no fetal cardiac activity). **Clinical Pearls for NEET-PG:** * **Most common site:** Ampulla of the Fallopian tube. * **Most common site for rupture:** Isthmus (occurs early, around 6–8 weeks). * **Arias-Stella Reaction:** Hypersecretory endometrium seen on biopsy; it is suggestive of pregnancy but not diagnostic of ectopic pregnancy. * **Gold Standard Diagnosis:** Laparoscopy (allows for both diagnosis and definitive treatment). * **Classic Triad:** Amenorrhea, abdominal pain, and vaginal bleeding (present in only 50% of cases).

Q: Which of the following represents fetal hypoxia, except:

Fetal scalp blood pH > 7.3. **Explanation:** Fetal hypoxia occurs when there is a deficiency in oxygen supply to the fetus, leading to anaerobic metabolism and metabolic acidosis. **Why Option C is the correct answer:** Fetal scalp blood sampling is the gold standard for assessing fetal acid-base status. A **pH > 7.25 is considered normal**. A pH between 7.20 and 7.25 is pre-pathological (borderline), and a **pH 7.3 represents a healthy, well-oxygenated fetus and is not a sign of hypoxia. **Analysis of Incorrect Options:** * **A. Excessive fetal movements:** Often referred to as "fetal alarm signals," a sudden burst of vigorous fetal activity followed by decreased movement can be an early clinical sign of acute hypoxia (the "struggle" phase). * **B. Meconium in vertex presentation:** Hypoxia causes increased intestinal peristalsis and relaxation of the anal sphincter, leading to the passage of meconium. While not always pathological, thick meconium in a vertex presentation is a classic warning sign of fetal distress. * **D. Heart rate < 100:** Persistent fetal bradycardia (FHR < 110 bpm) or late decelerations are hallmark electronic fetal monitoring (EFM) signs of hypoxia and impending fetal exhaustion. **NEET-PG High-Yield Pearls:** * **Normal Fetal pH:** 7.25 – 7.35. * **Critical pH for delivery:** If pH is < 7.20, immediate delivery is usually indicated. * **First sign of hypoxia on CTG:** Loss of variability (specifically short-term variability). * **Most specific sign of hypoxia:** Late decelerations. * **Modified Manning’s Criteria:** Combines Non-Stress Test (NST) and Amniotic Fluid Index (AFI).

Q: A Rh-negative mother with a negative indirect Coombs test is given Anti-D at 28 weeks of gestation. What is the recommended follow-up schedule for Anti-D immunoglobulin?

Administer another dose of Anti-D within 72 hours postpartum, based on the baby's blood group and direct Coombs test.. **Explanation:** The management of an Rh-negative pregnancy aims to prevent maternal alloimmunization. The standard protocol involves administering **300 mcg of Anti-D immunoglobulin at 28 weeks** of gestation (antenatal prophylaxis) to any non-sensitized Rh-negative woman (Indirect Coombs Test negative). **Why Option A is correct:** The antenatal dose covers the risk of silent feto-maternal hemorrhage (FMH) during the third trimester. However, the most significant risk of FMH occurs during delivery. Therefore, a second dose is required **within 72 hours postpartum**, but only if the newborn is **Rh-positive** and the **Direct Coombs Test (DCT)** on the cord blood is negative. If the baby is Rh-negative, no further Anti-D is needed as there is no risk of sensitization. **Analysis of Incorrect Options:** * **Option B:** Incorrect because Anti-D is unnecessary if the baby is Rh-negative. * **Option C:** Incorrect because Anti-D administration can cause a **false-positive ICT** (passive antibodies), which must be distinguished from true sensitization. * **Option D:** Incorrect because a single antenatal dose at 28 weeks provides adequate coverage until delivery in an uncomplicated pregnancy. **High-Yield Clinical Pearls for NEET-PG:** * **Standard Dose:** 300 mcg (1500 IU) of Anti-D neutralizes **30 ml of Rh-positive whole blood** (or 15 ml of packed RBCs). * **Kleihauer-Betke Test:** Used to quantify the volume of FMH to determine if additional doses of Anti-D are required postpartum. * **ICT vs. DCT:** ICT (Indirect) is done on maternal serum to detect antibodies; DCT (Direct) is done on fetal cord blood to detect antibodies bound to fetal RBCs. * **Early Pregnancy:** For sensitizing events before 12 weeks (e.g., abortion), a minidose of 50 mcg is sufficient.

Question 1

Which of the following laboratory tests supports the diagnosis of preeclampsia?

Accepted Answer

Platelet count 103,000 / μL

Answer

Creatinine 1.14 mg / dL

Answer

Alkaline phosphatase 138 IU / L

Answer

Total protein of 258 mg in 24-hour urine

Question 2

What is the dose of anti-D immunoglobulin to be given to non-immune Rh D negative women after delivery?

Accepted Answer

300 mcg

Answer

50 mcg

Answer

150 mcg

Answer

450 mcg

Question 3

After 20 weeks of gestation, what is the main contribution to amniotic fluid?

Accepted Answer

Fetal urine

Answer

Maternal serum filtered through the placenta

Answer

Transudate of fetal plasma through fetal skin

Answer

Transudate across the umbilical cord

Question 4

Hydramnios is complicated by which of the following conditions, EXCEPT?

Accepted Answer

Post-dated pregnancy

Answer

Placenta abruptio

Answer

Pre-eclampsia

Answer

Atonic Hemorrhage

Question 5

Abruptio placentae occurs in all except?

Accepted Answer

Alcoholics

Answer

Smokers

Answer

Pregnancy-induced hypertension

Answer

Folic acid deficiency

Question 6

Magnesium sulphate toxicity includes all of the following EXCEPT?

Accepted Answer

Oliguria

Answer

Loss of patellar reflex

Answer

Respiratory depression

Answer

Cardiac arrest

Question 7

All of the following are true about SLE in pregnancy except?

Accepted Answer

Increased anti-Ro and anti-La antibodies imply a low risk for congenital heart block.

Answer

Corticosteroids can be continued during pregnancy.

Answer

Recurrent abortions can be a manifestation of SLE in pregnancy.

Answer

The disease activity may worsen during pregnancy.

Question 8

Which of the following statements regarding ectopic pregnancy is true?

Accepted Answer

Serum progesterone >25 ng/ml excludes ectopic pregnancy.

Answer

p-hCG levels should be >1000 mIU/ml for earliest detection by TVS.

Answer

p-hCG levels should be <1000 mIU/ml for earliest detection by TVS.

Answer

Methotrexate is not used for the treatment of ectopic pregnancy.

Question 9

Which of the following represents fetal hypoxia, except:

Accepted Answer

Fetal scalp blood pH > 7.3

Answer

Excessive fetal movements

Answer

Meconium in vertex presentation

Answer

Heart rate < 100

Question 10

A Rh-negative mother with a negative indirect Coombs test is given Anti-D at 28 weeks of gestation. What is the recommended follow-up schedule for Anti-D immunoglobulin?

Accepted Answer

Administer another dose of Anti-D within 72 hours postpartum, based on the baby's blood group and direct Coombs test.

Answer

Administer another dose of Anti-D 72 hours postpartum, regardless of the baby's blood group.

Answer

Anti-D immunoglobulin has no effect on the status of the indirect Coombs test.

Answer

Administer the next dose of Anti-D at 34 weeks of gestation.

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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