Maternal-Fetal Medicine Practice Questions

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 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: Which of the following sonographic findings suggests the development of preeclampsia?

Increased volume of chorionic villi.. **Explanation:** Preeclampsia is fundamentally a disease of **defective placentation**. In a normal pregnancy, extravillous trophoblasts invade the maternal spiral arterioles, converting them from high-resistance, narrow vessels into low-resistance, high-capacity channels. In preeclampsia, this process fails. **1. Why Option A is Correct:** In preeclampsia, the placenta undergoes compensatory changes due to chronic hypoxia and ischemia. Sonographically and histologically, there is an **increase in the volume and surface area of chorionic villi** (specifically terminal villi) as the placenta attempts to maximize nutrient and oxygen exchange despite poor maternal perfusion. This is often associated with "villous hypervascularity" or "chorangiosis" in response to the hypoxic environment. **2. Why the Other Options are Incorrect:** * **Option B:** Extensive remodeling of spiral arterioles is a feature of a **normal pregnancy**. In preeclampsia, remodeling is incomplete or absent, restricted only to the decidual segments rather than the deeper myometrial segments. * **Option C:** Increased invasion of extravillous trophoblasts is characteristic of a healthy placenta. In preeclampsia, there is **shallow/reduced invasion**, leading to high-resistance placental circulation. **Clinical Pearls for NEET-PG:** * **Uterine Artery Doppler:** The most reliable sonographic predictor of preeclampsia is an **increased Pulsatility Index (PI)** and the presence of **diastolic notches** (beyond 24 weeks). * **Placental Morphology:** Preeclamptic placentas are often smaller, but may show sonographic "lakes," infarcts, or retroplacental hematomas. * **Biomarkers:** A high **sFlt-1/PlGF ratio** is a strong biochemical predictor of preeclampsia development.

Q: Post term pregnancy is defined as a pregnancy that continues beyond how many days from the first day of the last menstrual period?

294 days. **Explanation:** **1. Understanding the Correct Answer (C):** According to the **International Federation of Gynecology and Obstetrics (FIGO)** and the **American College of Obstetricians and Gynecologists (ACOG)**, a **post-term pregnancy** is defined as one that extends to or beyond **42 completed weeks** (294 days) from the first day of the last menstrual period (LMP). * **Calculation:** 42 weeks × 7 days/week = **294 days**. It is crucial to distinguish this from "late-term" pregnancy, which is defined as 41 weeks to 41 weeks and 6 days. **2. Analysis of Incorrect Options:** * **Option A (274 days):** This represents approximately 39 weeks. This is considered "Full Term" (39 0/7 to 40 6/7 weeks), which is the ideal window for delivery to minimize neonatal morbidity. * **Option B (284 days):** This represents approximately 40 weeks and 4 days. While this is past the Estimated Date of Delivery (EDD), it is classified as "Full Term" and does not meet the criteria for post-term. * **Option D (304 days):** This represents approximately 43 weeks and 3 days. While this is technically post-term, the definition begins at the completion of the 42nd week (294 days). **3. High-Yield Clinical Pearls for NEET-PG:** * **Terminology:** * **Early Term:** 37 0/7 – 38 6/7 weeks. * **Full Term:** 39 0/7 – 40 6/7 weeks. * **Late Term:** 41 0/7 – 41 6/7 weeks. * **Post-term:** ≥ 42 0/7 weeks. * **Most Common Cause:** The most common cause of a post-term pregnancy diagnosis is **inaccurate dating** (wrong LMP). * **Etiology:** Associated with placental sulfatase deficiency, anencephaly, and fetal adrenal hypoplasia. * **Risks:** Increased risk of **Macrosomia**, **Meconium Aspiration Syndrome**, and **Dysmaturity Syndrome** (due to placental insufficiency). * **Management:** Induction of labor is generally recommended between 41 and 42 weeks to prevent stillbirth.

Q: Which of the following drugs should not be used in the conduct of labour in a woman with rheumatic heart disease?

Methylergometrine. **Explanation:** In patients with Rheumatic Heart Disease (RHD), particularly those with Mitral Stenosis, the management of the third stage of labor is critical. The primary goal is to prevent sudden changes in hemodynamics and fluid overload. **Why Methylergometrine is contraindicated:** Methylergometrine (Methergine) is a potent vasoconstrictor. It causes **systemic vasoconstriction** and a sudden shift of blood from the peripheral circulation to the central compartment (autotransfusion). In a woman with RHD, this sudden increase in venous return (preload) can lead to acute pulmonary edema and heart failure. Additionally, it can cause a sharp rise in blood pressure. **Evaluation of other options:** * **Oxytocin (Option C):** This is the drug of choice for preventing Postpartum Hemorrhage (PPH) in cardiac patients. However, it must be administered as a **slow intravenous infusion**, never as a bolus, to avoid sudden hypotension. * **Carboprost (Option B):** While it can increase pulmonary artery pressure, it is not absolutely contraindicated like Methylergometrine; however, it is used with caution. * **Misoprostol (Option D):** This prostaglandin E1 analogue is safe for use in cardiac patients as it does not have significant effects on the cardiovascular system or vascular tone. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for PPH in RHD:** Oxytocin (slow IV drip). * **Drug of Choice for PPH in Asthma:** Oxytocin or Misoprostol (Avoid Carboprost/PGF2α). * **Drug of Choice for PPH in Hypertension/Preeclampsia:** Oxytocin (Avoid Methylergometrine). * **Management Tip:** In RHD patients, the second stage of labor is often shortened by using forceps or vacuum to prevent maternal exhaustion and tachycardia.

Question 1

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 2

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 3

Abruptio placentae occurs in all except?

Accepted Answer

Alcoholics

Answer

Smokers

Answer

Pregnancy-induced hypertension

Answer

Folic acid deficiency

Question 4

Magnesium sulphate toxicity includes all of the following EXCEPT?

Accepted Answer

Oliguria

Answer

Loss of patellar reflex

Answer

Respiratory depression

Answer

Cardiac arrest

Question 5

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 6

Which of the following is NOT a risk factor for preterm delivery?

Accepted Answer

Absence of fetal fibronectin at less than 37 weeks gestation

Answer

Previous history of preterm delivery

Answer

Asymptomatic cervical dilatation

Answer

Chlamydial infection of the genital tract

Question 7

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 8

Which of the following sonographic findings suggests the development of preeclampsia?

Accepted Answer

Increased volume of chorionic villi.

Answer

Extensive remodelling of spiral arterioles.

Answer

Increased invasion of extravillous trophoblastic tissue.

Answer

None of the above.

Question 9

Post term pregnancy is defined as a pregnancy that continues beyond how many days from the first day of the last menstrual period?

Accepted Answer

294 days

Answer

274 days

Answer

284 days

Answer

304 days

Question 10

Which of the following drugs should not be used in the conduct of labour in a woman with rheumatic heart disease?

Accepted Answer

Methylergometrine

Answer

Carboprost

Answer

Oxytocin

Answer

Misoprostol

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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