Maternal-Fetal Medicine Practice Questions

Q: A 23-year-old female presents with 42 days of amenorrhea and vaginal spotting. Which of the following is the most useful diagnostic test?

Transvaginal ultrasonography. **Explanation:** The clinical presentation of **amenorrhea (6 weeks) with vaginal spotting** is a classic triad for early pregnancy complications, most notably **ectopic pregnancy** or threatened abortion. **1. Why Transvaginal Ultrasonography (TVS) is the correct answer:** TVS is the gold standard and the most useful diagnostic tool in this scenario. At 6 weeks (42 days) of gestation, TVS can reliably identify an intrauterine gestational sac (visible at 4.5–5 weeks) or a yolk sac (visible at 5.5 weeks). Its primary utility is to **confirm the location of the pregnancy** (intrauterine vs. ectopic) and assess viability. In a patient with spotting, identifying the pregnancy's location is the immediate clinical priority. **2. Why the other options are incorrect:** * **Urine Pregnancy Test (UPT):** While it confirms pregnancy, it cannot differentiate between a healthy intrauterine pregnancy, a miscarriage, or a life-threatening ectopic pregnancy. * **Beta-hCG:** A single quantitative value is rarely diagnostic. It is most useful when used serially (to check doubling time) or in conjunction with TVS (the "Discriminatory Zone" concept). * **Serum Progesterone:** While low levels (<5 ng/mL) suggest a non-viable pregnancy, it cannot pinpoint the location or provide a definitive diagnosis. **Clinical Pearls for NEET-PG:** * **Discriminatory Zone:** The level of β-hCG at which an intrauterine sac should be visible on TVS is **1500–2000 mIU/mL**. If β-hCG is above this and the uterus is empty, suspect ectopic pregnancy. * **First Sign on TVS:** The "Intrachorionic sac" or "Double decidual sac sign" is the earliest sign of intrauterine pregnancy. * **Management Priority:** In any woman of reproductive age with amenorrhea and abdominal pain/spotting, **Ectopic Pregnancy** must be ruled out first using TVS.

Q: What is the most common cause of first-trimester abortion?

Chromosomal defect. **Explanation:** **1. Why Chromosomal Defect is Correct:** Chromosomal abnormalities are the single most common cause of spontaneous abortion in the first trimester, accounting for **50–70% of all cases**. These are usually sporadic (de novo) events resulting from errors in gametogenesis, such as non-disjunction. Among these, **Autosomal Trisomy** is the most frequent specific abnormality (Trisomy 16 being the most common), followed by Monosomy X (Turner Syndrome) and Triploidy. **2. Analysis of Incorrect Options:** * **Endocrine disturbances:** Conditions like Luteal Phase Defect (Progesterone deficiency), uncontrolled Diabetes Mellitus, and Thyroid disorders are significant causes but are statistically less frequent than genetic factors. * **Anatomic abnormality of the uterus:** Factors such as septate uterus, submucosal fibroids, or cervical incompetence more commonly lead to **second-trimester** losses rather than first-trimester abortions. * **Infections:** While TORCH infections, *Listeria*, and *Mycoplasma* can cause pregnancy loss, they are rare causes of early sporadic abortion in modern clinical practice. **3. NEET-PG High-Yield Pearls:** * **Most common Trisomy in abortus:** Trisomy 16 (Note: Trisomy 21 is the most common trisomy in live births). * **Most common single chromosomal anomaly:** Monosomy X (45,X). * **Second-trimester abortions:** Most commonly due to maternal factors (anatomic defects, systemic diseases) rather than fetal factors. * **Recurrent Pregnancy Loss (RPL):** Defined as ≥2 consecutive spontaneous abortions; the most common treatable cause is Antiphospholipid Antibody Syndrome (APS).

Q: A diabetic mother may have the following complications in the fetus EXCEPT:

Dimorphic anemia. **Explanation:** The correct answer is **Dimorphic anemia**. In diabetic pregnancies, the primary hematological complication in the fetus is **polycythemia** (not anemia). This occurs because fetal hyperglycemia leads to hyperinsulinemia, which increases the metabolic rate and oxygen consumption. The resulting fetal hypoxia stimulates erythropoietin production, leading to an excess of red blood cells. **Analysis of Options:** * **Hydramnios (Polyhydramnios):** This is a common complication. Fetal hyperglycemia causes osmotic diuresis, leading to **fetal polyuria**, which increases the volume of amniotic fluid. * **Macrosomia:** Maternal hyperglycemia results in fetal hyperinsulinemia. Since insulin is a potent growth-promoting hormone, it leads to excessive fat deposition and organomegaly, typically resulting in a birth weight >4000g. * **Cardiac Anomaly:** Pre-gestational diabetes is teratogenic. The most common cardiac defect is a **Ventricular Septal Defect (VSD)**, though **Transposition of the Great Arteries (TGA)** and Hypertrophic Cardiomyopathy (septal hypertrophy) are also highly associated. **NEET-PG High-Yield Pearls:** 1. **Most common malformation:** Cardiovascular anomalies. 2. **Most specific malformation:** **Caudal Regression Syndrome** (Sacral agenesis). 3. **Metabolic triad in neonate:** Hypoglycemia, Hypocalcemia, and Hypomagnesemia. 4. **Respiratory risk:** Delayed surfactant production leads to an increased risk of **Respiratory Distress Syndrome (RDS)**, even in near-term infants.

Q: What is the best prenatal treatment for Congenital Adrenal Hyperplasia (CAH)?

Dexamethasone. **Explanation:** The primary goal of prenatal treatment for **Congenital Adrenal Hyperplasia (CAH)**, specifically the 21-hydroxylase deficiency variant, is to prevent the **virilization (masculinization)** of a female fetus by suppressing the fetal pituitary-adrenal axis. **Why Dexamethasone is the Correct Answer:** Dexamethasone is a potent glucocorticoid that **crosses the placenta** without being inactivated by the placental enzyme **11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2)**. By reaching the fetal circulation, it suppresses fetal ACTH secretion, thereby reducing the production of adrenal androgens that cause ambiguous genitalia in female fetuses. Treatment must be started early (before the 9th week of gestation) to be effective. **Why Other Options are Incorrect:** * **Prednisolone & Hydrocortisone:** These steroids are largely **inactivated** by the placental enzyme 11β-HSD2. Consequently, they do not reach the fetus in therapeutic concentrations and are ineffective for prenatal fetal treatment (though they are used to treat the mother). * **Betamethasone:** While betamethasone also crosses the placenta, it is primarily used for **fetal lung maturity** in cases of preterm labor. Clinical protocols for CAH specifically standardize the use of Dexamethasone (0.02 mg/kg/day). **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Treatment must begin **empirically** as soon as pregnancy is confirmed (ideally by 6–7 weeks), before the sex of the fetus or the genetic status is known. * **Target:** Treatment is only necessary for **female fetuses** affected by CAH. If the fetus is male or an unaffected female (determined via CVS or NIPT), Dexamethasone is discontinued. * **Mechanism:** It works by providing negative feedback to the fetal hypothalamus/pituitary, preventing the "androgen shower" that occurs during the critical period of genital differentiation.

Q: Highest rate of transmission of toxoplasmosis to the fetus during pregnancy is seen in which trimester?

Third trimester. **Explanation:** The risk of vertical transmission of *Toxoplasma gondii* is directly proportional to the gestational age at the time of maternal infection. **1. Why the Third Trimester is Correct:** The rate of transmission is highest in the **third trimester (60–80%)**. This is primarily due to the increased permeability and surface area of the placenta, along with enhanced uterine blood flow as pregnancy progresses, which facilitates the passage of tachyzoites from the mother to the fetus. **2. Why Other Options are Incorrect:** * **First Trimester:** While the risk of transmission is lowest here (approx. 10–15%), the **severity** of fetal damage is highest (e.g., miscarriage, severe neurological deficits). * **Second Trimester:** The transmission rate is intermediate (approx. 25–30%). * **Puerperium:** This refers to the period after delivery. Congenital toxoplasmosis occurs due to *in utero* infection, not during the postpartum period. **3. High-Yield Clinical Pearls for NEET-PG:** * **Inverse Relationship:** Remember the "Rule of Inverses"—as gestational age increases, the **risk of transmission increases**, but the **severity of fetal disease decreases**. * **Classic Triad (Sabin’s Triad):** Chorioretinitis, Hydrocephalus, and Intracranial calcifications (usually diffuse). * **Diagnosis:** Maternal screening is done via IgM/IgG titers. Fetal diagnosis is best confirmed via **PCR of Amniotic fluid** (Gold Standard). * **Treatment:** * If maternal infection is suspected but fetal infection is not confirmed: **Spiramycin** (to prevent transmission). * If fetal infection is confirmed: **Pyrimethamine, Sulfadiazine, and Folinic acid**.

Q: All of the following are adverse outcomes associated with threatened abortion, except:

Fetal macrosomia. **Explanation:** Threatened abortion (vaginal bleeding before 20 weeks of gestation with a closed cervix) is not just an isolated early pregnancy event; it is a marker of **defective placentation**. When the early attachment of the placenta is disrupted, it leads to a higher risk of late-pregnancy complications. **Why Fetal Macrosomia is the Correct Answer:** Fetal macrosomia (Option D) is **not** associated with threatened abortion. In fact, the opposite is true. Due to impaired placental function and chronic placental insufficiency following early bleeding, there is an increased risk of **Low Birth Weight (LBW)** and **Intrauterine Growth Restriction (IUGR)**. Macrosomia is typically associated with gestational diabetes or post-term pregnancy. **Analysis of Incorrect Options:** * **Preterm Birth (Option B):** This is the most common late-pregnancy complication of threatened abortion. Inflammation and decidual hemorrhage can trigger premature rupture of membranes or early labor. * **Placenta Previa (Option A):** Early bleeding may be associated with low implantation of the blastocyst. Furthermore, subchorionic hematomas can influence the final position and attachment of the placenta. * **Manual Removal of Placenta (Option C):** Threatened abortion increases the risk of morbidly adherent placenta (Placenta Accreta spectrum) and retained products, often necessitating manual removal due to abnormal placental-decidual interface. **NEET-PG High-Yield Pearls:** * **Most common cause of threatened abortion:** Genetic/Chromosomal abnormalities (e.g., Autosomal trisomy). * **Prognostic Marker:** The presence of fetal cardiac activity on ultrasound in a case of threatened abortion indicates a >90% chance of pregnancy continuation. * **Other associated risks:** Abruptio placentae, Pregnancy-Induced Hypertension (PIH), and increased perinatal mortality.

Question 1

A 23-year-old female presents with 42 days of amenorrhea and vaginal spotting. Which of the following is the most useful diagnostic test?

Accepted Answer

Transvaginal ultrasonography

Answer

Urine pregnancy test

Answer

Beta-hCG

Answer

Serum progesterone

Question 2

A 26-year-old woman, who underwent mitral valve replacement two years ago for severe mitral stenosis and is currently on therapeutic anticoagulation with 5mg of Warfarin daily, seeks preconception counseling. Which of the following statements is FALSE?

Accepted Answer

Warfarin should be stopped periconceptionally and switched to heparin.

Answer

The risk of warfarin embryopathy is approximately 6%.

Answer

Anticoagulation must continue throughout pregnancy.

Answer

The prognosis for her pregnancy is influenced by her NYHA functional class.

Question 3

What is the most common cause of first-trimester abortion?

Accepted Answer

Chromosomal defect

Answer

Endocrine disturbances

Answer

Anatomic abnormality of the uterus

Answer

Infections

Question 4

A diabetic mother may have the following complications in the fetus EXCEPT:

Accepted Answer

Dimorphic anemia

Answer

Hydramnios

Answer

Macrosomia

Answer

Cardiac anomaly

Question 5

Which type of delivery is safest in maternal heart disease?

Accepted Answer

Outlet forceps

Answer

Vaginal

Answer

Cesarean section

Answer

Mid-cavity forceps

Question 6

A 32-year-old female, unable to conceive for 6 years, presents with a missed period of three weeks, left-sided lower abdominal pain, and nausea. B subunit human chorionic gonadotropin (HCG) and pelvic ultrasound confirm an ectopic pregnancy. What is the appropriate management?

Accepted Answer

If unruptured, the fallopian tube should be spared

Answer

Immediate laparotomy and salpingectomy

Answer

Avoid incidental appendectomy

Answer

If the patient is hemodynamically stable, surgery should be avoided

Question 7

What is the best prenatal treatment for Congenital Adrenal Hyperplasia (CAH)?

Accepted Answer

Dexamethasone

Answer

Betamethasone

Answer

Prednisolone

Answer

Hydrocortisone

Question 8

Highest rate of transmission of toxoplasmosis to the fetus during pregnancy is seen in which trimester?

Accepted Answer

Third trimester

Answer

First trimester

Answer

Second trimester

Answer

Puerperium

Question 9

A 19-year-old woman, gravida 2, para 0, abortion 1, is at 30 weeks gestation. Her fundal height measures 25cm. An obstetrical ultrasound examination reveals a 4-quadrant amniotic fluid index (AFI) of 4cm. Which of the following fetal conditions is associated with this finding?

Accepted Answer

Renal agenesis

Answer

Duodenal atresia

Answer

Open spina bifida

Answer

Tracheoesophageal fistula

Question 10

All of the following are adverse outcomes associated with threatened abortion, except:

Accepted Answer

Fetal macrosomia

Answer

Placenta previa

Answer

Preterm birth

Answer

Manual removal of placenta

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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