Maternal-Fetal Medicine Practice Questions

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.

Q: Which of the following statements concerning placenta previa is true?

The initial hemorrhage is usually painless and rarely fatal. **Explanation:** Placenta previa occurs when the placenta implants in the lower uterine segment, partially or completely covering the internal os. **Why Option B is correct:** The hallmark of placenta previa is **painless, bright red vaginal bleeding**. This occurs because, as the lower uterine segment stretches and thins in the third trimester, the placental attachments are disrupted. The initial bleed (sentinel bleed) is typically self-limiting and **rarely fatal** to the mother, as it is not usually associated with the massive coagulopathy or concealed hemorrhage seen in placental abruption. **Why the other options are incorrect:** * **Option A:** While maternal age is a risk factor, the **strongest risk factor** is a history of previous Cesarean sections or uterine surgeries (e.g., myomectomy). * **Option C:** The "double setup" (preparing for a vaginal delivery in an OR ready for immediate CS) is largely **obsolete**. Modern management relies on ultrasound for diagnosis. If placenta previa is confirmed, a scheduled Cesarean section is the standard of care. * **Option D:** Digital vaginal examination is **strictly contraindicated** (the "No PV" rule) until placenta previa is ruled out by ultrasound. A finger passed through the cervix can cause catastrophic, life-threatening hemorrhage by piercing the placental substance. **NEET-PG High-Yield Pearls:** * **Best Initial Investigation:** Transabdominal Ultrasound (95% accuracy). * **Gold Standard Investigation:** Transvaginal Ultrasound (TVS) – it is safe and more accurate for measuring the distance from the internal os. * **Maclean-Johnson Protocol:** Expectant management (bed rest, steroids, observation) used for preterm patients (<37 weeks) who are hemodynamically stable. * **Stallworthy’s Sign:** A dip in the fetal heart rate when the head is pushed into the pelvis, suggestive of posterior placenta previa.

Q: The classic triad of ruptured ectopic pregnancy includes all EXCEPT?

Fainting. The classic clinical triad of ectopic pregnancy is a high-yield concept for NEET-PG. Understanding the difference between the "classic triad" and "symptoms of rupture" is key to answering this question correctly. ### **Explanation** The **classic triad** of ectopic pregnancy consists of: 1. **Abdominal pain:** The most common symptom (95–100%), usually localized to the iliac fossa. 2. **Amenorrhea:** A history of a missed period (75–90%), typically 6–8 weeks prior. 3. **Vaginal bleeding:** Usually slight, dark brown "spotting" (70%), occurring after the onset of pain. **Fainting (Option A)** is the correct answer because it is **not** part of the classic triad. While fainting or syncope occurs in ruptured ectopic pregnancy due to intraperitoneal hemorrhage and hypovolemic shock, it is considered a **sign of rupture/complication** rather than a component of the primary diagnostic triad. ### **Analysis of Incorrect Options** * **Abdominal Pain (Option B):** The primary presenting symptom caused by tubal distension or peritoneal irritation. * **History of Amenorrhea (Option C):** Essential for the suspicion of any pregnancy-related pathology. * **Vaginal Bleeding (Option D):** Caused by the shedding of the decidua due to falling progesterone levels; it is a core component of the triad. ### **Clinical Pearls for NEET-PG** * **Gold Standard Investigation:** Transvaginal Ultrasound (TVS) + Serum β-hCG. * **Discriminatory Zone:** The β-hCG level (usually 1500–2000 mIU/mL) at which a gestational sac should be visible on TVS. * **Arias-Stella Reaction:** Hypersecretory endometrium seen on curettage, characteristic of (but not pathognomonic for) ectopic pregnancy. * **Most Common Site:** Ampulla of the Fallopian tube. * **Most Common Site of Rupture:** Isthmus (occurs early, around 6–8 weeks).

Question 1

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

Accepted Answer

Dexamethasone

Answer

Betamethasone

Answer

Prednisolone

Answer

Hydrocortisone

Question 2

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 3

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 4

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

Question 5

Which of the following statements concerning placenta previa is true?

Accepted Answer

The initial hemorrhage is usually painless and rarely fatal

Answer

Its incidence increases with maternal age

Answer

Management still includes a double setup

Answer

Vaginal examination should be done immediately on suspicion of placenta previa

Question 6

Which of the following is a non-invasive test used to diagnose fetal Rh genotype in Rh D alloimmunization?

Accepted Answer

Cell-free fetal DNA analysis

Answer

Chorionic villus sampling

Answer

Amniocentesis

Answer

Middle cerebral artery peak systolic velocity

Question 7

Which of the following statements is true?

Accepted Answer

Phosphatidyl glycerol in amniotic fluid is 100% confirmatory of lung maturity.

Answer

Glyburide is absolutely contraindicated for GDM.

Answer

Patients with GDM/DM should be delivered between 34 and 36 weeks of gestation due to the risk of sudden IUFD at full term.

Answer

PTH crosses the placenta.

Question 8

What is the treatment for acute hydramnios with respiratory depression?

Accepted Answer

Amniocentesis

Answer

Termination of pregnancy

Answer

Diuretics

Answer

Sedation

Question 9

USG abdomen of a 30-year-old SLE patient who cannot feel her baby moving for the past 7 days. What is the earliest appearance of Spalding sign?

Accepted Answer

7 days

Answer

3 days

Answer

4 days

Answer

6 days

Question 10

The classic triad of ruptured ectopic pregnancy includes all EXCEPT?

Accepted Answer

Fainting

Answer

Abdominal pain

Answer

History of amenorrhea

Answer

Vaginal bleeding

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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