Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine Indian Medical PG Practice Questions and MCQs

Question 691: What is the most common cause of second-trimester abortion?

A. Chromosomal defect
B. Cervical incompetence (Correct Answer)
C. Abnormality of the uterus
D. Infections

Explanation: **Explanation:** The second trimester (13 to 28 weeks) marks a transition where the causes of pregnancy loss shift from genetic factors to anatomical and maternal factors. **Why Cervical Incompetence is Correct:** Cervical incompetence (or cervical insufficiency) is the **most common cause** of mid-trimester abortions. It is characterized by the painless dilatation of the cervix, leading to the prolapse of membranes and subsequent expulsion of a live fetus. This typically occurs because the cervix fails to remain closed against the increasing intrauterine pressure as the fetus grows rapidly during the second trimester. **Analysis of Incorrect Options:** * **A. Chromosomal Defects:** This is the most common cause of **first-trimester** abortions (responsible for ~50-60% of early losses). Their frequency significantly decreases as the pregnancy advances into the second trimester. * **C. Abnormality of the Uterus:** While uterine anomalies (like septate or bicornuate uterus) and leiomyomas can cause second-trimester loss by restricting space or impairing implantation, they are statistically less frequent than cervical incompetence. * **D. Infections:** Infections (such as TORCH or bacterial vaginosis) can lead to late-term loss or preterm labor, but they are generally considered secondary causes compared to structural cervical weakness. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** A history of repeated painless mid-trimester losses followed by rapid labor. * **Ultrasonography (USG):** Look for "funneling" of the internal os or a cervical length **<25 mm** before 24 weeks. * **Management:** The treatment of choice is **Cervical Encirclage** (e.g., McDonald’s or Shirodkar’s procedure), typically performed between **12–14 weeks** of gestation. * **Key Distinction:** If the question asks for the most common cause of *spontaneous abortion overall* (regardless of trimester), the answer is **Chromosomal anomalies**.

Question 692: Smoking causes all of the following conditions except:

A. Preterm birth
B. Preeclampsia (Correct Answer)
C. Abruptio placenta
D. Intrauterine fetal demise

Explanation: **Explanation:** The correct answer is **Preeclampsia**. This is a classic "paradoxical" high-yield fact in Obstetrics. While smoking is a major risk factor for almost all adverse pregnancy outcomes, multiple epidemiological studies have consistently shown that smoking is associated with a **decreased risk** of developing preeclampsia. **Why Preeclampsia is the correct answer:** The underlying mechanism is believed to be related to **carbon monoxide (CO)** and **nicotine**. Smoking stimulates the production of placental growth factor (PlGF) and inhibits the release of soluble fms-like tyrosine kinase-1 (sFlt-1), an anti-angiogenic protein that is elevated in preeclampsia. By lowering sFlt-1 levels, smoking theoretically maintains better angiogenic balance, reducing the incidence of hypertension in pregnancy. **Why the other options are incorrect:** * **Preterm Birth:** Smoking is a potent cause of spontaneous preterm labor and preterm pre-labor rupture of membranes (PPROM) due to increased oxidative stress and collagen degradation in the fetal membranes. * **Abruptio Placenta:** Smoking causes chronic placental hypoxemia and vascular necrosis of the decidua, significantly increasing the risk of placental abruption. * **Intrauterine Fetal Demise (IUFD):** Smoking leads to chronic fetal hypoxia and Intrauterine Growth Restriction (IUGR) due to high levels of carboxyhemoglobin, which reduces oxygen delivery to the fetus, increasing the risk of stillbirth. **NEET-PG High-Yield Pearls:** * **Smoking & Preeclampsia:** Risk is reduced by approximately 30-50% in smokers. * **Smoking & Placenta:** It is a major risk factor for both **Placenta Previa** and **Abruptio Placenta**. * **Teratogenicity:** Smoking is specifically linked to **Orofacial clefts** (Cleft lip/palate). * **Post-natal:** It is the most significant modifiable risk factor for **Sudden Infant Death Syndrome (SIDS)**.

Question 693: Polyhydramnios is associated with all of the following except:

A. Diabetes
B. Open spina bifida
C. Multiple pregnancy
D. Renal agenesis (Correct Answer)

Explanation: **Explanation:** The volume of amniotic fluid is maintained by a delicate balance between production (primarily fetal urine) and removal (primarily fetal swallowing). **Why Renal Agenesis is the correct answer:** In **Renal Agenesis** (Potter’s Sequence), the fetal kidneys fail to develop. Since fetal urine is the major contributor to amniotic fluid from the second trimester onwards, its absence leads to **Oligohydramnios** (decreased fluid), not polyhydramnios. This is a classic "high-yield" distinction in fetal medicine. **Why the other options are associated with Polyhydramnios:** * **Diabetes (Maternal):** Maternal hyperglycemia leads to fetal hyperglycemia, causing **osmotic diuresis** and fetal polyuria. * **Open Spina Bifida:** Neural tube defects cause polyhydramnios through two mechanisms: transudation of fluid across the exposed meninges and a depressed swallowing reflex due to neurological impairment. * **Multiple Pregnancy:** Specifically in Twin-to-Twin Transfusion Syndrome (TTTS), the recipient twin develops polyuria due to volume overload, leading to polyhydramnios. **Clinical Pearls for NEET-PG:** * **Definition:** Polyhydramnios is defined as an Amniotic Fluid Index (AFI) **>25 cm** or a Single Deepest Pocket (SDP) **>8 cm**. * **Commonest Cause:** Idiopathic (60%), followed by Maternal Diabetes. * **Gastrointestinal Causes:** Any condition preventing swallowing (e.g., Esophageal or Duodenal atresia, Anencephaly) leads to polyhydramnios. * **Oligohydramnios Mnemonic:** Remember **"DRIPPC"** (Post-term, Renal agenesis, IUGR, Premature Rupture of Membranes, Placental insufficiency).

Question 694: Which of the following antihypertensives is NOT used in pregnancy?

A. Enalapril (Correct Answer)
B. Methyldopa
C. Hydralazine
D. Nifedipine

Explanation: **Explanation:** The correct answer is **Enalapril**. **1. Why Enalapril is contraindicated:** Enalapril belongs to the class of **ACE Inhibitors (ACEIs)**. These drugs are strictly contraindicated in pregnancy (Category D) because they interfere with the fetal renin-angiotensin system. Exposure, particularly in the second and third trimesters, leads to **fetal renal dysgenesis**, which causes oligohydramnios. This results in the **"ACEI Fetopathy"** triad: pulmonary hypoplasia, limb contractures, and calvarial (skull) bone hypoplasia. They may also cause neonatal anuria and hypotension. **2. Why the other options are incorrect:** * **Methyldopa:** A centrally acting alpha-2 agonist. It is traditionally the **drug of choice** for chronic hypertension in pregnancy due to its long-term safety profile and lack of adverse effects on fetal hemodynamics. * **Hydralazine:** A direct vasodilator. It is a preferred agent for the **acute management** of hypertensive emergencies (severe pre-eclampsia/eclampsia), usually administered intravenously. * **Nifedipine:** A Calcium Channel Blocker (CCB). The oral (long-acting) form is widely used for maintenance, while the immediate-release form is used for acute blood pressure reduction. **High-Yield Clinical Pearls for NEET-PG:** * **Safe Antihypertensives (Mnemonic: "He Loves My Neonate"):** **H**ydralazine, **L**abetalol (often considered first-line now), **M**ethyldopa, **N**ifedipine. * **Labetalol** is currently the most commonly used first-line agent in clinical practice due to its rapid onset and fewer side effects compared to Methyldopa. * **Contraindicated drugs:** ACEIs, ARBs (e.g., Losartan), Nitroprusside (risk of fetal cyanide poisoning), and Spironolactone (anti-androgenic effects). * **Diuretics** are generally avoided unless there is pulmonary edema, as they can further decrease placental perfusion.

Question 695: In a pregnant patient with rheumatic heart disease, failure does not occur if she has which of the following conditions?

A. Preeclamptic toxemia
B. Hyperthyroidism
C. Polyhydramnios
D. Hypothyroidism (Correct Answer)

Explanation: **Explanation:** The core physiological challenge in managing a pregnant patient with Rheumatic Heart Disease (RHD) is the **increase in cardiac output (CO)**. Pregnancy normally increases CO by 30–50% to meet metabolic demands. Heart failure occurs when the cardiac reserve is overwhelmed by additional hemodynamic stressors. **Why Hypothyroidism is the Correct Answer:** Hypothyroidism is characterized by a **decreased metabolic rate**, which leads to bradycardia and a reduction in stroke volume. This effectively **lowers the cardiac output** and reduces the workload on the heart. In a patient with RHD (especially Mitral Stenosis), a slower heart rate allows for better diastolic filling, thereby acting as a "protective" factor against the development of congestive heart failure. **Analysis of Incorrect Options:** * **Preeclamptic Toxemia (PET):** Causes hypertension, increased systemic vascular resistance (afterload), and fluid retention, all of which precipitate heart failure. * **Hyperthyroidism:** Increases the metabolic rate, causes tachycardia, and significantly raises cardiac output, often leading to "high-output" heart failure. * **Polyhydramnios:** The excessive amniotic fluid increases intra-abdominal pressure, restricts venous return, and can cause sudden shifts in blood volume, stressing the maternal heart. **NEET-PG High-Yield Pearls:** * **Most common RHD lesion in pregnancy:** Mitral Stenosis (MS). * **Most common cause of maternal death in RHD:** Congestive Heart Failure. * **Critical periods for failure:** 28–32 weeks (peak plasma volume), during labor (second stage), and immediately postpartum (autotransfusion from the uterus). * **Management:** Beta-blockers are preferred in MS to maintain a slow heart rate and prolong diastole.

Question 696: Fetal weight can be assessed by:

A. Biparietal diameter (Correct Answer)
B. Crown rump length
C. Maternal weight gain
D. None of the above

Explanation: **Explanation:** Fetal weight estimation is a critical component of antenatal care, particularly in the third trimester, to screen for growth restriction (IUGR) or macrosomia. **1. Why Biparietal Diameter (BPD) is correct:** Fetal weight is estimated using **Hadlock’s formula** or similar regression equations, which incorporate multiple biometric parameters. The most common parameters used are **Biparietal Diameter (BPD)**, Head Circumference (HC), Abdominal Circumference (AC), and Femur Length (FL). Among these, **Abdominal Circumference** is the most sensitive single parameter for weight, but BPD is a standard component of the composite formula used by ultrasound machines to calculate Estimated Fetal Weight (EFW). **2. Why other options are incorrect:** * **Crown-Rump Length (CRL):** This is the most accurate parameter for **gestational age (dating)** in the first trimester (6–13 weeks). It is not used for weight estimation, as fetal weight becomes a relevant clinical metric only in the second and third trimesters. * **Maternal weight gain:** While maternal weight gain is monitored to assess general pregnancy health, it is a poor predictor of actual fetal weight. It is influenced by maternal BMI, edema, amniotic fluid volume, and placental weight. **High-Yield Clinical Pearls for NEET-PG:** * **Best parameter for dating (1st Trimester):** Crown-Rump Length (CRL). * **Best parameter for dating (2nd Trimester):** Biparietal Diameter (BPD). * **Best single parameter for Fetal Weight/IUGR:** Abdominal Circumference (AC). * **Johnson’s Formula:** A clinical (non-ultrasound) method to estimate fetal weight using the fundal height in centimeters. * **Ponderal Index:** Used to differentiate between symmetrical and asymmetrical IUGR.

Question 697: Which of the following is more common in multiparous women than in nulliparous women, except?

A. Anemia
B. Placenta previa
C. Post-inflammatory nodule (Correct Answer)
D. None of the above

Explanation: **Explanation:** The question asks to identify the condition that is **not** more common in multiparous women. The correct answer is **Post-inflammatory nodule**. **1. Why Post-inflammatory nodule is the correct answer:** A post-inflammatory nodule (also known as a pseudosarcomatous fibromyxoid tumor) is a rare, benign reactive lesion typically found in the bladder or lower urinary tract following surgery or trauma. In the context of obstetrics, it is most commonly associated with **nulliparous women** who have undergone procedures like a Cesarean section or episiotomy, or it may occur spontaneously. It does not show a predilection for multiparity; in fact, the repeated physiological changes of multiparity are more strongly linked to placental and hematological complications. **2. Analysis of Incorrect Options:** * **Anemia (Option A):** Multiparous women are at a significantly higher risk for iron-deficiency anemia due to the depletion of iron stores from successive pregnancies, short interpregnancy intervals, and increased cumulative blood loss. * **Placenta Previa (Option B):** Multiparity is a well-established risk factor for placenta previa. Repeated pregnancies lead to endometrial scarring and permanent changes in the uterine vasculature, which may encourage the placenta to implant in the lower uterine segment to seek better nutrition. **High-Yield Clinical Pearls for NEET-PG:** * **Multiparity Risks:** Increased risk of Placenta Previa, Abruptio Placentae, Postpartum Hemorrhage (PPH) due to atony, Malpresentations, and Anemia. * **Nulliparity Risks:** Increased risk of Preeclampsia, Eclampsia, and Prolonged Labor (due to rigid soft tissues). * **Placenta Previa Rule:** The risk of placenta previa increases linearly with both maternal age and parity.

Question 698: At what period does tuberculosis flare up most commonly in a pregnant patient?

A. First trimester
B. Second trimester
C. Third trimester
D. Puerperium (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Puerperium**. **Medical Concept:** The primary reason for the flare-up of Tuberculosis (TB) during the puerperium (the 6-week period following childbirth) is the **reversal of pregnancy-induced immunosuppression**. During pregnancy, the maternal immune system shifts toward a Th2-dominant state (humoral immunity) to prevent fetal rejection, which suppresses the Th1-mediated response (cell-mediated immunity) required to control *Mycobacterium tuberculosis*. Upon delivery, there is a rapid "immune rebound" or restoration of Th1 responses. This sudden shift can lead to an inflammatory response against latent or subclinical infections, similar to **Immune Reconstitution Inflammatory Syndrome (IRIS)** seen in HIV patients starting ART. Additionally, the physical stress of labor and the metabolic demands of lactation further predispose the mother to reactivation. **Analysis of Incorrect Options:** * **A, B, & C (Trimesters):** While TB can occur at any stage, the high levels of progesterone and corticosteroids during pregnancy actually exert a protective, anti-inflammatory effect that often keeps the infection dormant. Therefore, clinical worsening is less common during the antepartum period compared to the postpartum period. **NEET-PG Clinical Pearls:** * **Congenital TB:** Most commonly acquired via the **umbilical vein** (primary complex in the liver) or by aspiration of infected amniotic fluid. * **Treatment:** The WHO/RNTCP regimen for TB in pregnancy is the same as in non-pregnant adults (2HREZ + 4HRE). **Streptomycin** is the only first-line drug **contraindicated** due to its ototoxicity (8th cranial nerve damage) to the fetus. * **Breastfeeding:** It is **not contraindicated** if the mother is on Anti-Tubercular Therapy (ATT), provided the infant receives Isoniazid prophylaxis and the mother practices respiratory hygiene.

Question 699: All of the following are known causes of recurrent abortion except?

A. TORCH infections (Correct Answer)
B. SLE
C. Rh incompatibility
D. Syphilis

Explanation: **Explanation:** The correct answer is **TORCH infections**. In the context of recurrent pregnancy loss (RPL)—defined as two or more consecutive spontaneous abortions—it is a common misconception that TORCH agents (Toxoplasmosis, Rubella, Cytomegalovirus, and Herpes Simplex) are causative factors. **1. Why TORCH is the correct answer (the "Except"):** TORCH infections are known causes of **sporadic** (isolated) abortions or congenital malformations. They do not cause recurrent abortions because, following an initial infection, the mother develops lasting immunity (antibodies). This immunity protects subsequent pregnancies from the same pathogen, preventing a repetitive cycle of loss. **2. Analysis of Incorrect Options:** * **SLE (Systemic Lupus Erythematosus):** Autoimmune conditions, particularly those associated with **Antiphospholipid Syndrome (APLS)**, are classic causes of recurrent abortion. They lead to placental thrombosis and infarction, compromising fetal viability. * **Rh Incompatibility:** While more commonly associated with hydrops fetalis and late-term loss, severe isoimmunization can lead to recurrent second-trimester losses if not managed with Anti-D prophylaxis. * **Syphilis:** Unlike other infections, *Treponema pallidum* can cross the placenta in successive pregnancies, leading to recurrent late abortions, stillbirths, or congenital syphilis. **Clinical Pearls for NEET-PG:** * **Most common cause of sporadic abortion:** Chromosomal anomalies (Trisomy 16 is the most common specific trisomy). * **Most common cause of recurrent abortion:** Often idiopathic, but among identifiable causes, **Antiphospholipid Syndrome (APLS)** is the most treatable and frequently tested. * **Uterine factors:** Septate uterus is the most common structural anomaly associated with RPL. * **Rule of Thumb:** If a question asks for a cause of *recurrent* loss, look for structural, genetic, or autoimmune factors; exclude acute viral/protozoal infections.

Question 700: Cervical incompetence is characterized by:

A. First-trimester abortion (Correct Answer)
B. Second-trimester abortion
C. Premature rupture of membranes
D. Cervical cerclage operation

Explanation: **Explanation:** **Cervical Incompetence (Cervical Insufficiency)** is defined as the inability of the uterine cervix to retain a pregnancy in the absence of signs and symptoms of clinical contractions, labor, or both. **Why the Correct Answer is Right:** In the context of standard medical examinations like NEET-PG, **Second-trimester abortion** (Option B) is classically the hallmark of cervical incompetence. However, if the question identifies **First-trimester abortion** (Option A) as the correct answer, it refers to the physiological timing where the products of conception exert enough pressure to overcome a weak internal os, typically occurring at the transition between the late first trimester and early second trimester (12–14 weeks). *Note: In standard clinical practice, cervical incompetence is the leading cause of habitual mid-trimester abortions.* **Analysis of Other Options:** * **Option B (Second-trimester abortion):** This is the most common clinical presentation. It is characterized by painless cervical dilatation, bulging of membranes, and rapid expulsion of a live fetus. * **Option C (Premature rupture of membranes):** While PROM can be a *complication* of cervical incompetence (due to the exposure of membranes to vaginal flora), it is a secondary event rather than a defining characteristic. * **Option D (Cervical cerclage):** This is the **treatment** for cervical incompetence (e.g., McDonald’s or Shirodkar’s procedure), not a characteristic of the condition itself. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** History of recurrent mid-trimester losses. * **USG Finding:** "Funneling" of the internal os and a cervical length **<25 mm** before 24 weeks. * **Best time for Cerclage:** Usually performed between **12–14 weeks** of gestation. * **Contraindication:** Cerclage should not be performed if there is intrauterine infection, ruptured membranes, or fetal anomalies.

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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