Maternal-Fetal Medicine Practice Questions

Q: Which of the following statements regarding monozygotic twins is not true?

They are always monochorionic. **Explanation:** **1. Why Option C is the Correct Answer (The "False" Statement):** Monozygotic (MZ) twins are not always monochorionic. The chorionicity and amnionicity depend entirely on the **timing of the zygotic split**. If the split occurs early (within the first 3 days post-fertilization, at the morula stage), the twins will be **Dichorionic Diamniotic (DCDA)**, just like dizygotic twins. Approximately 25–30% of monozygotic twins are DCDA. **2. Analysis of Other Options:** * **Option A:** Ultrasound is indeed more useful in the first half (specifically the first trimester) for determining chorionicity. Signs like the **'Lambda' (T-sign)** are most accurate before 14 weeks. * **Option B:** While MZ twins are genetically identical, sex discordance can occur rarely due to **post-zygotic non-disjunction** (e.g., one twin is 46,XY and the other is 45,X Turner syndrome) or in cases of phenotypic discordance in disorders of sexual development. * **Option C:** Assisted Reproductive Technology (ART) and ovulation induction are known risk factors that increase the incidence of monozygotic twinning, likely due to micromanipulation of the zona pellucida. **3. High-Yield Clinical Pearls for NEET-PG:** * **The "Rule of Split":** * 0–3 days: DCDA (25-30%) * 4–8 days: Monochorionic Diamniotic (MCDA) — **Most common (70-75%)** * 8–13 days: Monochorionic Monoamniotic (MCMA) — High risk (1-2%) * >13 days: Conjoined twins (Rare) * **T-sign vs. Lambda sign:** Lambda (λ) sign indicates Dichorionic; T-sign indicates Monochorionic. * **Twin-to-Twin Transfusion Syndrome (TTTS):** Occurs only in monochorionic pregnancies.

Q: Which of the following is NOT helpful in the diagnosis of a tubal mass in ectopic pregnancy?

Hysterosalpingography. **Explanation:** The diagnosis of ectopic pregnancy relies on a combination of clinical assessment, biochemical markers, and imaging. **Why Hysterosalpingography (HSG) is the Correct Answer:** HSG is a radiologic procedure used primarily to assess tubal patency in infertility workups. It involves injecting radiopaque contrast into the uterine cavity and tubes under pressure. In a suspected ectopic pregnancy, HSG is **contraindicated** and not helpful because: 1. It carries a high risk of **rupturing** the ectopic gestation. 2. It can cause severe infection or introduce contrast into the peritoneal cavity. 3. It provides no diagnostic value compared to non-invasive imaging. **Analysis of Other Options:** * **Beta-HCG Estimation:** This is the "gold standard" biochemical marker. A positive pregnancy test confirms gestation, and serial titers (looking for a sub-optimal doubling time) help differentiate an ectopic pregnancy from a viable intrauterine one. * **Transvaginal Ultrasound (TVS):** This is the imaging modality of choice. It can visualize an adnexal mass (e.g., "bagel sign" or "blob sign"), a gestational sac outside the uterus, or free fluid in the Pouch of Douglas. * **Pelvic Examination:** Clinical examination is essential. Findings such as cervical motion tenderness (Chandelier sign) and a palpable, tender adnexal mass are classic indicators of a tubal pregnancy. **NEET-PG High-Yield Pearls:** * **Classic Triad:** Amenorrhea, abdominal pain, and vaginal bleeding (present in only 50% of cases). * **Discriminatory Zone:** The level of 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. * **Most Common Site:** The **Ampulla** of the fallopian tube. * **Most Common Site for Rupture:** The **Isthmus** (due to its narrow lumen).

Q: What is a common cause of recurrent second-trimester fetal loss?

Abnormality of cervix and uterus. **Explanation:** Recurrent pregnancy loss (RPL) is etiologically distinct depending on the gestational age. **Abnormalities of the cervix and uterus** are the most common causes of recurrent **second-trimester** losses. Specifically, **Cervical Insufficiency** (painless cervical dilation) and structural uterine anomalies (such as a septate or bicornuate uterus) or acquired lesions (like submucosal fibroids or intrauterine synechiae) compromise the structural integrity required to hold a growing fetus, leading to mid-trimester expulsions. **Analysis of Options:** * **A. Chromosomal anomaly:** This is the most common cause of **first-trimester** sporadic and recurrent abortions (approx. 50-60%). Their incidence decreases significantly as pregnancy advances into the second trimester. * **B. Intrauterine infection:** While infections (e.g., TORCH, bacterial vaginosis) can cause sporadic mid-trimester loss or preterm labor, they are rarely responsible for *recurrent* losses. * **D. Hormonal imbalance:** Conditions like Luteal Phase Defect (LPD) or uncontrolled diabetes are primarily associated with implantation failure or early first-trimester losses. **High-Yield Clinical Pearls for NEET-PG:** * **Cervical Insufficiency:** Characterized by painless cervical ripening and spontaneous mid-trimester abortion. The gold standard treatment is **McDonald’s or Shirodkar’s Cerclage**, typically performed at 12–14 weeks. * **Uterine Septum:** The most common uterine anomaly associated with recurrent pregnancy loss. * **Antiphospholipid Syndrome (APS):** The most important *treatable* autoimmune cause of recurrent second-trimester loss due to placental thrombosis. * **Rule of Thumb:** 1st Trimester = Genetic/Chromosomal; 2nd Trimester = Anatomic/Structural.

Q: True about abruptio placentae, all are correct except?

Placenta lying in the lower segment.. **Explanation:** Abruptio placentae is defined as the premature separation of a **normally situated placenta** from the uterine wall before the birth of the fetus. **Why Option B is the Correct Answer (The Exception):** The hallmark of abruptio placentae is that the placenta is located in the **upper uterine segment**. If the placenta is implanted in the **lower uterine segment**, the condition is termed **Placenta Previa**. Therefore, Option B is factually incorrect regarding abruption and is the correct choice for this "except" question. **Analysis of Other Options:** * **Option A:** Chronic hypertension and Preeclampsia are the most significant predisposing risk factors for abruption due to maternal vascular degenerative changes. * **Option C:** In abruption, blood often extravasates into the myometrium (Couvelaire uterus), leading to uterine irritability. This manifests clinically as a **woody-hard, board-like, and tender uterus**. * **Option D:** Unlike the episodic, painless bleeding of placenta previa, the bleeding in abruption is typically **continuous** and associated with abdominal pain. **NEET-PG High-Yield Pearls:** * **Most common cause of DIC in obstetrics:** Abruptio Placentae. * **Couvelaire Uterus:** Utero-placental apoplexy where blood seeps into the myometrium (diagnosed via laparotomy). * **Classification:** Revealed (blood escapes), Concealed (blood trapped behind placenta), and Mixed (most common). * **Key Clinical Triad:** Abdominal pain, uterine tenderness, and vaginal bleeding (in revealed/mixed types).

Q: A 31-year-old woman in her second trimester of pregnancy presents with dyspnea on exertion. She has no history of chest pain, cough, or fever, and no known cardiac disease. Physical examination reveals a pulse of 75/min, BP of 110/70 mmHg, and SpO2 of 96%. Chest and cardiovascular examinations are unremarkable. What is the most probable cause of this patient's clinical presentation?

Physiological dyspnea of pregnancy. **Explanation:** **Physiological dyspnea of pregnancy** is the most likely diagnosis. It affects approximately 60–75% of pregnant women, typically beginning in the first or second trimester. The underlying mechanism is primarily hormonal: increased levels of **progesterone** act as a direct respiratory stimulant, increasing the sensitivity of the respiratory center to CO2. This leads to **hyperventilation** (increased tidal volume), which results in a physiological state of mild respiratory alkalosis. Clinically, the patient remains comfortable at rest, and physical examination (vitals, chest auscultation) is characteristically normal. **Why other options are incorrect:** * **Asthma:** Usually presents with a history of atopy, cough, wheezing, or chest tightness. Physical exam would typically reveal expiratory wheeze. * **Pulmonary Embolism (PE):** While pregnancy is a hypercoagulable state, PE usually presents with sudden-onset dyspnea, tachycardia, tachypnea, and often pleuritic chest pain or hypoxia (SpO2 <95%). * **Left Heart Failure:** This would present with orthopnea, paroxysmal nocturnal dyspnea, and clinical signs like pulmonary crackles (rales), an S3 gallop, or peripheral edema. **High-Yield Clinical Pearls for NEET-PG:** * **Respiratory Changes:** Pregnancy increases **Tidal Volume** (by 40%) and **Minute Ventilation**, but **Functional Residual Capacity (FRC)** and **Residual Volume** decrease due to the elevating diaphragm. * **ABG Profile:** Normal pregnancy shows a compensated **respiratory alkalosis** (pH 7.40–7.45, pCO2 27–32 mmHg). * **Vital Signs:** A respiratory rate >20/min or SpO2 <95% is **never** physiological in pregnancy and warrants investigation for pathology.

Q: Patients with organic heart disease in pregnancy most commonly die during which period?

Soon following delivery. **Explanation:** The correct answer is **Soon following delivery** (Option C). The period immediately following the delivery of the placenta is the most critical for a woman with organic heart disease. This is due to a phenomenon known as **"Autotransfusion."** When the placenta is delivered, the compression of the inferior vena cava is relieved, and the blood previously circulating in the uteroplacental unit (approx. 500-800 mL) is shifted back into the maternal systemic circulation. This sudden increase in venous return leads to a massive surge in cardiac output (up to 60-80% above baseline), which can overwhelm a compromised heart, leading to acute pulmonary edema and heart failure. **Analysis of Incorrect Options:** * **A. 20-24 weeks:** While cardiac output begins to rise significantly during the second trimester, it reaches its peak plateau between **28-32 weeks**. This is a period of high risk, but not the most common time for mortality compared to the immediate postpartum surge. * **B. First stage of labor:** Cardiac output increases during labor due to pain, anxiety, and uterine contractions (each contraction pushes ~300-500 mL of blood into circulation), but the peak hemodynamic stress occurs after the fetus is expelled. * **D. Two weeks postpartum:** By this time, hemodynamic stability is usually restored as the excess fluid has been diuresed. **High-Yield Clinical Pearls for NEET-PG:** * **Maximum Risk Periods:** 1. Immediately postpartum (highest risk), 2. During labor, 3. 28-32 weeks of gestation. * **Management:** To prevent heart failure during the third stage, avoid ergometrine (causes vasoconstriction) and use slow IV infusion of oxytocin. * **Positioning:** Encourage the left lateral position to minimize caval compression. * **Vaginal vs. C-Section:** Vaginal delivery with an assisted second stage (forceps/ventouse) to cut short maternal bearing down is preferred over elective Cesarean section.

Q: An ultrasound shows a twin pregnancy. Which of the following is a feature of dizygotic twins?

Separate chorion and amnion. **Explanation:** **1. Why Option B is Correct:** Dizygotic (fraternal) twins result from the fertilization of **two separate ova by two separate sperm**. Because each zygote undergoes its own independent process of implantation and development, each fetus develops its own placenta, its own outer membrane (chorion), and its own inner sac (amnion). Therefore, dizygotic twins are **always Dichorionic-Diamniotic (DCDA)**. **2. Why the Other Options are Incorrect:** * **Option A (Separate amnion and same chorion):** This describes Monochorionic-Diamniotic (MCDA) twins. This configuration is unique to **monozygotic** (identical) twins where the zygote splits between days 4 and 8 post-fertilization. Dizygotic twins can never share a chorion. * **Option C (Always different sex):** This is a common misconception. Since two separate sperm are involved, the sex of each twin is independent. They can be the same sex (approx. 50% of the time) or different sexes. Only "different sex" twins are guaranteed to be dizygotic, but dizygotic twins are not "always" different sex. **3. NEET-PG High-Yield Pearls:** * **Zygosity vs. Chorionicity:** All dizygotic twins are DCDA. Monozygotic twins can be DCDA, MCDA, or MCMA depending on the timing of the split. * **The "Lambda" vs. "T" Sign:** On ultrasound, a thick membrane with the **Lambda (λ) sign** (or twin-peak sign) indicates DCDA (Dizygotic or early-split Monozygotic). A thin membrane with a **T-sign** indicates MCDA. * **Incidence:** The rate of monozygotic twins is constant worldwide (~1 in 250), whereas the rate of dizygotic twins varies by race (highest in Nigerians, lowest in Japanese), maternal age, and use of assisted reproductive technology (ART).

Question 1

Which of the following statements regarding monozygotic twins is not true?

Accepted Answer

They are always monochorionic

Answer

Ultrasound is more useful in the first half of pregnancy

Answer

Sex discordance can occur rarely

Answer

They are more common following ovulation induction

Question 2

Which of the following is NOT helpful in the diagnosis of a tubal mass in ectopic pregnancy?

Accepted Answer

Hysterosalpingography

Answer

Beta-HCG estimation

Answer

Transvaginal ultrasound

Answer

Pelvic examination

Question 3

A 23-year-old primigravida at 33 weeks gestation presented with jaundice for 2 days. On examination, her BP was 140/90 mmHg, serum bilirubin was 5 mg%, Hb was 8 gm%, platelet count was 90,000/cu.mm, TLC was 10,000/cu.mm, and blood sugar was 40 mg/dL. AST and ALT were 85 and 80 IU/L, respectively. What is the probable diagnosis?

Accepted Answer

Acute fatty liver in pregnancy

Answer

Acute Hepatitis A

Answer

HELLP syndrome

Answer

Acute hepatitis E

Question 4

What is a common cause of recurrent second-trimester fetal loss?

Accepted Answer

Abnormality of cervix and uterus

Answer

Chromosomal anomaly

Answer

Intrauterine infection

Answer

Hormonal imbalance

Question 5

True about abruptio placentae, all are correct except?

Accepted Answer

Placenta lying in the lower segment.

Answer

Hypertension in pregnancy is an important predisposing factor.

Answer

Tender and hard uterus.

Answer

Continuous bleeding per vaginum.

Question 6

A 31-year-old woman in her second trimester of pregnancy presents with dyspnea on exertion. She has no history of chest pain, cough, or fever, and no known cardiac disease. Physical examination reveals a pulse of 75/min, BP of 110/70 mmHg, and SpO2 of 96%. Chest and cardiovascular examinations are unremarkable. What is the most probable cause of this patient's clinical presentation?

Accepted Answer

Physiological dyspnea of pregnancy

Answer

Asthma

Answer

Pulmonary embolism

Answer

Left heart failure

Question 7

Patients with organic heart disease in pregnancy most commonly die during which period?

Accepted Answer

Soon following delivery

Answer

20-24 weeks of pregnancy

Answer

First stage of labor

Answer

Two weeks postpartum

Question 8

An ultrasound shows a twin pregnancy. Which of the following is a feature of dizygotic twins?

Accepted Answer

Separate chorion and amnion

Answer

Separate amnion and same chorion

Answer

Always different sex

Answer

None of the above

Question 9

Which of the following complications is seen in pregnancy?

Accepted Answer

Hypertension complicating pregnancy

Answer

Diabetes complicating pregnancy

Answer

Placenta previa complicating pregnancy

Answer

Preterm delivery

Question 10

A 32-year-old primigravida woman at 20 weeks gestation has blood group O positive. Her husband has blood group AB positive. Which of the following is the most appropriate response to the patient's query, given that she and her husband have different blood groups and have already experienced a pregnancy?

Accepted Answer

Newborns affected by ABO incompatibility will have only mild hemolytic disease.

Answer

ABO antigens elicit only an IgM response, which does not cross the placenta.

Answer

Antibodies to ABO antigens are not hemolytic.

Answer

She is not at risk as the immune response is depressed during pregnancy.

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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