Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine Indian Medical PG Practice Questions and MCQs

Question 391: Which one of the following is categorized as a high-risk pregnancy?

A. Birth order 3
B. Maternal height 150 cm
C. Twins pregnancy (Correct Answer)
D. Blood group AB positive

Explanation: **Explanation:** A **high-risk pregnancy** is defined as one in which the mother, the fetus, or the newborn is at an increased risk of morbidity or mortality due to factors complicating the pregnancy. **Why "Twins Pregnancy" is Correct:** Multiple gestations (twins, triplets, etc.) are inherently high-risk because they significantly increase the risk of both maternal and fetal complications. * **Maternal risks:** Preeclampsia (3x higher risk), gestational diabetes, anemia, and postpartum hemorrhage (due to uterine overdistension). * **Fetal risks:** Preterm birth (the most common complication), intrauterine growth restriction (IUGR), malpresentation, and specific risks like Twin-to-Twin Transfusion Syndrome (TTTS) in monochorionic twins. **Analysis of Incorrect Options:** * **Birth order 3:** Generally, the "Grand Multipara" (Para 4 or more) is considered high-risk due to risks of placenta previa, malpresentation, and atonic PPH. A third pregnancy is typically considered a "safe" parity. * **Maternal height 150 cm:** In the Indian context, a "short-statured" mother is defined as having a height **<145 cm** (or 140 cm in some guidelines). 150 cm is above the threshold for increased risk of Cephalopelvic Disproportion (CPD). * **Blood group AB positive:** This is the "universal recipient" and does not pose an immunological risk. High-risk blood groups include **Rh-negative** (risk of isoimmunization) or rare blood groups where cross-matching may be difficult during emergencies. **NEET-PG High-Yield Pearls:** * **Primi-elderly:** Age >30 years (some texts say >35). * **Short Stature:** Height <145 cm (associated with contracted pelvis). * **Anemia in Pregnancy:** Hb <11 g/dL (WHO). * **Previous LSCS:** Always categorized as high-risk due to the risk of scar dehiscence or morbidly adherent placenta.

Question 392: A female presents with leaking and meconium-stained liquor at 32 weeks gestation. Which organism is she most likely infected with?

A. Cytomegalovirus (CMV)
B. Listeria monocytogenes (Correct Answer)
C. Toxoplasma gondii
D. Herpes simplex virus (HSV)

Explanation: **Explanation:** The presence of **meconium-stained liquor (MSL)** in a preterm pregnancy (especially before 34 weeks) is a classic clinical red flag for **Listeria monocytogenes** infection. **Why Listeria monocytogenes is correct:** Listeria is a gram-positive motile bacillus typically transmitted via contaminated food (unpasteurized cheese, cold meats). In pregnancy, it has a unique tropism for the placenta. It causes "granulomatosis infantiseptica" and is notorious for inducing **amnionitis**. A hallmark of Listeria infection is the passage of meconium in utero by a preterm fetus, which is otherwise rare, as the fetal gastrointestinal tract is usually too immature to pass meconium before 34 weeks unless severely stressed by this specific pathogen. **Why other options are incorrect:** * **CMV (Option A):** The most common congenital infection; typically presents with periventricular calcifications, microcephaly, and IUGR, but not acute MSL. * **Toxoplasma gondii (Option C):** Presents with the classic triad of hydrocephalus, chorioretinitis, and intracranial calcifications. It does not typically cause preterm leaking with MSL. * **HSV (Option D):** Usually transmitted during delivery through the birth canal, leading to skin-eye-mouth (SEM) lesions or encephalitis in the neonate. It is not associated with preterm meconium passage. **Clinical Pearls for NEET-PG:** * **Listeria** is the only Gram-positive bacteria that produces an **endotoxin**. * It shows **"tumbling motility"** at 25°C. * **Drug of Choice:** Ampicillin (Listeria is inherently resistant to cephalosporins). * **High-Yield Association:** Preterm labor + Fever + Meconium-stained liquor = Think **Listeria**.

Question 393: An Rh-negative woman married to a heterozygous Rh-positive man has three children. What is the probability that all three of their children are Rh-positive?

A. 1:2
B. 1:4
C. 1:8 (Correct Answer)
D. Zero

Explanation: ### Explanation **1. Why the Correct Answer (C) is Right:** The inheritance of the Rh factor follows Mendelian genetics. In this scenario: * **Mother:** Rh-negative (Genotype: **dd**) * **Father:** Heterozygous Rh-positive (Genotype: **Dd**) Using a Punnett square for each pregnancy: * Possible offspring genotypes: **Dd** (Rh-positive) or **dd** (Rh-negative). * The probability of having an Rh-positive child in **each** pregnancy is **1/2 (50%)**. Since each pregnancy is an independent event, the probability of all three children being Rh-positive is calculated using the multiplication rule: **1/2 (1st child) × 1/2 (2nd child) × 1/2 (3rd child) = 1/8.** **2. Why Other Options are Wrong:** * **Option A (1:2):** This is the probability for a *single* child to be Rh-positive, not all three. * **Option B (1:4):** This would be the probability if only *two* children were Rh-positive. * **Option D (Zero):** This would only be possible if the father were also Rh-negative (dd). **3. Clinical Pearls for NEET-PG:** * **Rh Incompatibility:** Occurs only when the mother is Rh-negative and the fetus is Rh-positive. * **Homozygous Father:** If the father were homozygous Rh-positive (DD), **100%** of the children would be Rh-positive. * **Anti-D Prophylaxis:** Administered at 28 weeks of gestation and within 72 hours of delivery to prevent sensitization. * **Kleihauer-Betke Test:** Used to quantify fetal-maternal hemorrhage to determine the required dose of Rh-immunoglobulin. * **Critical Titer:** An Indirect Coombs Test (ICT) titer of **1:16** is generally considered the critical threshold requiring further fetal surveillance (e.g., MCA-PSV Doppler).

Question 394: A pregnant woman at 18 weeks gestation is found to have an abdominal pregnancy with the fetus and placenta attached to the omentum. What is the best course of action?

A. Removal of both fetus and placenta
B. Laparoscopic ligation of umbilical cord
C. Removal of the fetus only (Correct Answer)
D. Close follow-up until viability and then delivery by laparotomy

Explanation: **Explanation:** In abdominal pregnancy, the management of the placenta is the most critical decision. Unlike an intrauterine pregnancy, there is no uterine contraction to constrict blood vessels after placental separation. **Why "Removal of the fetus only" is correct:** When the placenta is attached to a highly vascular or vital organ (like the omentum, bowel, or large vessels), attempting to remove it can lead to **uncontrollable, life-threatening hemorrhage**. The standard surgical recommendation is to ligate the umbilical cord close to the placenta and leave the placenta *in situ*. The placenta will eventually undergo spontaneous resorption, a process that can be monitored using serial β-hCG levels and ultrasound. **Analysis of Incorrect Options:** * **Option A:** Removing the placenta carries a high risk of massive bleeding because the site lacks the "living ligatures" (myometrial fibers) found in the uterus. * **Option B:** While the cord is ligated, the fetus must be removed to prevent infection, lithopedion formation, or maternal inflammatory response. Ligation alone is insufficient. * **Option C:** Waiting for viability is extremely dangerous. Abdominal pregnancies are associated with high maternal mortality (up to 7-8 times higher than tubal ectopic) and a high risk of sudden placental abruption or organ rupture. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Suggested by "painful fetal movements," easily palpable fetal parts, and an empty uterus on ultrasound. * **Placental Management:** If the placenta is left behind, **Methotrexate** is generally **avoided** as it causes rapid placental necrosis, leading to infection and abscess formation. * **Classification:** Primary abdominal pregnancy (rare) vs. Secondary (more common, usually following tubal abortion/rupture). * **Criteria:** Studdiford’s Criteria are used to diagnose primary abdominal pregnancy.

Question 395: Bleeding that follows partial or complete placental separation and dilation of the cervical os in the first 20 weeks is termed as what?

A. Threatened abortion
B. Complete abortion
C. Incomplete abortion (Correct Answer)
D. Preterm labor

Explanation: ### Explanation **Correct Answer: C. Incomplete abortion** **1. Why it is correct:** An **incomplete abortion** is defined as the partial expulsion of the products of conception before 20 weeks of gestation. Pathophysiologically, it involves the separation of the placenta (either partially or completely) from the uterine wall. Because some products remain inside the uterus while others have passed, the **cervical os remains dilated** to allow for the passage of tissue. This leads to persistent bleeding and cramp-like pain. **2. Why the other options are incorrect:** * **A. Threatened abortion:** In this condition, the pregnancy is potentially viable. While bleeding occurs, the **cervical os remains closed**, and there is no expulsion of tissue. * **B. Complete abortion:** Here, all products of conception have been expelled. Consequently, the **cervical os closes**, the uterus is well-contracted (small for dates), and bleeding diminishes significantly. * **D. Preterm labor:** This refers to the onset of labor (regular contractions and cervical changes) **after 20 weeks** (or 28 weeks depending on regional definitions) but before 37 completed weeks. The question specifically mentions the first 20 weeks. **3. NEET-PG High-Yield Pearls:** * **Cervical Os Status:** This is the most critical clinical differentiator. The os is **closed** in Threatened and Complete abortions; it is **open** in Inevitable and Incomplete abortions. * **Ultrasonography (USG) findings:** In an incomplete abortion, USG shows "retained products of conception" (RPOCs) and an endometrial thickness usually >15 mm. * **Management:** The treatment of choice for incomplete abortion is **Dilation and Evacuation (D&E)** or medical management with Misoprostol to ensure the uterus is empty and to prevent hemorrhage or sepsis. * **Definition of Abortion:** Termination of pregnancy before **20 weeks** (WHO) or a fetal weight less than **500g**.

Question 396: Which fetal parameter is best for diagnosing Intrauterine Growth Restriction (IUGR)?

A. Femur length
B. Head circumference
C. Abdominal circumference (Correct Answer)
D. Crown-rump length (CRL)

Explanation: **Explanation:** **Abdominal Circumference (AC)** is the most sensitive and reliable single parameter for diagnosing Intrauterine Growth Restriction (IUGR). This is because IUGR—specifically the asymmetrical type—primarily affects the fetal liver size and subcutaneous fat deposition. The fetal liver is the largest organ in the abdomen, and its size is directly dependent on glycogen storage. In cases of placental insufficiency, glycogen stores are depleted first, leading to a reduction in liver volume and a subsequent decrease in AC before other parameters are affected. **Analysis of Options:** * **Femur Length (FL):** Reflects skeletal growth. It is usually preserved until the late stages of growth restriction and is therefore not a sensitive early indicator. * **Head Circumference (HC):** In asymmetrical IUGR, the "brain-sparing effect" ensures that blood flow is prioritized to the brain. Consequently, HC remains relatively normal while the body wastes, making it a poor diagnostic tool for growth restriction. * **Crown-Rump Length (CRL):** This is the most accurate parameter for **gestational age estimation** in the first trimester, but it has no role in diagnosing IUGR, which is typically a second or third-trimester pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Best single parameter for IUGR:** Abdominal Circumference (AC). * **Best parameter for Gestational Age (1st Trimester):** Crown-Rump Length (CRL). * **Best parameter for Gestational Age (2nd/3rd Trimester):** Head Circumference (HC). * **Ponderal Index:** Used to differentiate between symmetrical and asymmetrical IUGR. * **Early sign of IUGR on Doppler:** Increased resistance/Reduced end-diastolic flow in the Umbilical Artery.

Question 397: A woman presents with amenorrhea for 8 weeks, acute abdominal pain, and vaginal discharge. Which is the most appropriate investigation to rule out ectopic pregnancy?

A. Urine pregnancy test
B. Laparoscopy (Correct Answer)
C. Ultrasound (USG)
D. Hysteroscopy

Explanation: **Explanation:** The clinical presentation of amenorrhea, acute abdominal pain, and vaginal bleeding (often misidentified as discharge) is the classic triad of **ectopic pregnancy**. **Why Laparoscopy is the correct answer:** Laparoscopy is considered the **gold standard** for the diagnosis of ectopic pregnancy. In an acute presentation where a definitive diagnosis is required to rule out or confirm an ectopic gestation, laparoscopy allows for direct visualization of the fallopian tubes and pelvic cavity. It is both a diagnostic and a therapeutic tool, as surgical management (salpingectomy or salpingostomy) can be performed in the same sitting. **Analysis of Incorrect Options:** * **Urine Pregnancy Test (UPT):** While a UPT is the first-line screening test to confirm pregnancy, it cannot differentiate between an intrauterine and an ectopic pregnancy. A negative UPT makes ectopic pregnancy unlikely, but a positive one is not diagnostic of the location. * **Ultrasound (USG):** Transvaginal Sonography (TVS) is the primary imaging modality used to locate a pregnancy. However, in early stages or "pregnancy of unknown location" (PUL), USG may be inconclusive. It is highly suggestive but not as definitive as direct visualization via laparoscopy. * **Hysteroscopy:** This involves visualizing the interior of the uterine cavity. It has no role in diagnosing an ectopic pregnancy (which occurs outside the uterus) and is contraindicated if a viable intrauterine pregnancy is suspected. **NEET-PG High-Yield Pearls:** * **Gold Standard Investigation:** Laparoscopy. * **Most Common Site:** Ampulla of the Fallopian tube. * **Most Common Site for Rupture:** Isthmus (due to its narrow lumen). * **Discriminatory Zone:** The level of serum β-hCG (usually 1500–2000 mIU/ml) at which a gestational sac should be visible on TVS. If β-hCG is above this and the uterus is empty, suspect ectopic pregnancy. * **Arias-Stella Reaction:** Hypersecretory endometrium seen on histology, suggestive of pregnancy but not specific to ectopic.

Question 398: What is the tocolytic of choice in HELLP syndrome?

A. Nifedipine
B. Atosiban (Correct Answer)
C. Magnesium sulfate
D. Salbutamol

Explanation: **Explanation:** The management of HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets) often necessitates delivery; however, if the pregnancy is extremely preterm and tocolysis is required to complete a course of corticosteroids for fetal lung maturity, **Atosiban** is the preferred choice. **Why Atosiban is correct:** Atosiban is an oxytocin receptor antagonist. Its primary advantage in HELLP syndrome is its **minimal side-effect profile**, particularly regarding the cardiovascular and hepatic systems. Unlike other tocolytics, it does not cause significant hypotension, tachycardia, or fluid overload, making it the safest option in a patient already physiologically compromised by endothelial dysfunction and potential coagulopathy. **Analysis of Incorrect Options:** * **Nifedipine (Calcium Channel Blocker):** While a first-line tocolytic in routine preterm labor, it can cause hypotension and may interfere with magnesium sulfate (increasing the risk of neuromuscular blockade). In HELLP, it may also mask or complicate the management of severe hypertension. * **Magnesium Sulfate:** While used in HELLP syndrome for **seizure prophylaxis** (neuroprotection), it is a very weak tocolytic and is not used primarily to arrest labor. * **Salbutamol (Beta-mimetics):** These are contraindicated in HELLP/Preeclampsia due to risks of maternal tachycardia, hyperglycemia, and, most critically, **pulmonary edema**, which is a known complication of severe preeclampsia. **NEET-PG High-Yield Pearls:** * **Drug of Choice for Tocolysis (General):** Nifedipine is generally the first-line tocolytic for preterm labor. * **Tocolytic in Heart Disease/Diabetes:** Atosiban is the preferred choice. * **HELLP Definitive Treatment:** Delivery of the fetus (usually after 34 weeks or if maternal/fetal condition deteriorates). * **Steroids in HELLP:** Dexamethasone is often used to increase platelet counts, though its effect on overall prognosis is debated.

Question 399: Rh isoimmunization is typically identified in which trimester?

A. 10-12 weeks
B. 30-32 weeks (Correct Answer)
C. 36 weeks
D. Immediately after delivery

Explanation: **Explanation:** 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. While sensitization can occur at any time during pregnancy due to feto-maternal hemorrhage (FMH), the risk increases significantly as the pregnancy progresses. **Why 30-32 weeks is the correct answer:** The volume of feto-maternal hemorrhage increases with advancing gestational age. By the **early third trimester (around 28-32 weeks)**, the cumulative risk of "silent" or spontaneous FMH is high enough to cause detectable isoimmunization in a significant number of susceptible women. This is the physiological basis for administering routine antenatal anti-D prophylaxis at 28 weeks. If a woman is to become sensitized during the pregnancy itself (rather than at delivery), it is most commonly identified during this window. **Analysis of Incorrect Options:** * **10-12 weeks:** FMH is rare and usually involves a very small volume of blood in the first trimester. Sensitization at this stage is uncommon unless associated with miscarriage or invasive procedures. * **36 weeks:** While sensitization can occur here, it is usually detected earlier during routine screening protocols. * **Immediately after delivery:** This is the most common time for the *largest* volume of FMH to occur (during placental separation). However, the question asks when isoimmunization is typically *identified* during the course of pregnancy monitoring. **High-Yield Clinical Pearls for NEET-PG:** * **Standard Screening:** Indirect Coombs Test (ICT) is performed at the first booking visit and repeated at **28 weeks**. * **Prophylaxis:** 300 mcg of Anti-D is given at 28 weeks if the ICT is negative. * **Postpartum:** If the neonate is Rh-positive, a second dose of 300 mcg Anti-D is given within 72 hours of delivery. * **Kleihauer-Betke Test:** Used to quantify the volume of FMH to determine if additional doses of Anti-D are required (10 mcg per 1 mL of fetal whole blood).

Question 400: The Kleihauer Betke test for detecting fetal erythrocytes is based on which principle?

A. Adult erythrocytes are larger than fetal erythrocytes.
B. HbA has higher oxygen affinity than HbF.
C. HbF is more resistant to acid elution than HbA. (Correct Answer)
D. HbA takes up erythrosin stain less effectively than HbF.

Explanation: ### Explanation The **Kleihauer-Betke (KB) test** is the gold standard for quantifying the volume of **fetal-maternal hemorrhage (FMH)**. **1. Why Option C is Correct:** The test relies on the biochemical difference between **Hemoglobin F (fetal)** and **Hemoglobin A (adult)**. When a maternal blood smear is exposed to an **acid bath (citrate-phosphate buffer)**, adult hemoglobin (HbA) is unstable and leaches out of the cells, leaving behind empty "ghost cells." In contrast, fetal hemoglobin (HbF) is **acid-resistant** and remains within the erythrocytes. When a counterstain (like eosin or erythrosin) is applied, the fetal cells take up the stain and appear bright pink/dark, while maternal cells appear pale or colorless. **2. Analysis of Incorrect Options:** * **Option A:** Cell size is not the distinguishing factor; both fetal and adult RBCs are similar in size (though fetal RBCs have a slightly higher MCV, it is not the basis for this chemical test). * **Option B:** While HbF does have a higher oxygen affinity than HbA, this physiological property is used for gas exchange in utero, not for laboratory elution tests. * **Option D:** The staining difference is a *result* of the acid elution process, not a primary difference in the innate staining affinity of the hemoglobins themselves. **3. Clinical Pearls for NEET-PG:** * **Indications:** Used to calculate the dose of **Rh Anti-D immunoglobulin** required after a large FMH (e.g., trauma, placental abruption). * **Formula:** Volume of FMH (mL) = (Number of fetal cells / Total cells counted) × Maternal Blood Volume (approx. 5000 mL). * **Dosage:** 300 µg of Anti-D neutralizes **30 mL** of fetal whole blood (or 15 mL of packed RBCs). * **Limitation:** The test is unreliable in mothers with conditions that elevate HbF, such as **Sickle Cell Anemia or Thalassemia**.

Practice by Chapter

Fetal Assessment Techniques

Practice Questions

Hypertensive Disorders in Pregnancy

Practice Questions

Intrauterine Growth Restriction

Practice Questions

Multiple Gestation

Practice Questions

Rh Isoimmunization and Other Blood Group Incompatibilities

Practice Questions

Intrauterine Fetal Therapy

Practice Questions

Prenatal Diagnosis and Genetic Counseling

Practice Questions

Placental Abnormalities

Practice Questions

Preterm Labor and Delivery

Practice Questions

Management of Medical Disorders in Pregnancy

Practice Questions

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