Maternal-Fetal Medicine Practice Questions

Q: All of the following are components of the biophysical profile except?

Fetal heart rate baseline. **Explanation:** The **Biophysical Profile (BPP)**, also known as Manning’s score, is a non-invasive ultrasound-based assessment used to evaluate fetal well-being and identify potential hypoxia. It consists of five specific parameters, each scored as either 2 (normal) or 0 (abnormal). **Why Option D is Correct:** The correct answer is **Fetal heart rate baseline**. While fetal heart rate is a component of the BPP, it is assessed specifically via a **Non-Stress Test (NST)** to look for **reactivity** (accelerations), not the baseline rate itself. A baseline heart rate alone does not provide sufficient information about the acute acid-base status of the fetus in the context of a BPP. **Analysis of Incorrect Options:** The five components of the BPP (Mnemonic: **BATMAN** – Breathing, Amniotic fluid, Tone, Movement, and NST) include: * **A. Amniotic fluid volume:** A marker of chronic fetal oxygenation (assessed by a single deepest vertical pocket >2 cm). * **B. Fetal breathing movements:** At least one episode of rhythmic breathing lasting ≥30 seconds in 30 minutes. * **C. Gross fetal body movements:** At least three discrete body or limb movements in 30 minutes. * **E. Fetal Tone (not listed in options):** At least one episode of active extension with return to flexion of a limb or trunk. **High-Yield Clinical Pearls for NEET-PG:** * **Modified BPP:** Consists of only two parameters: **NST** (indicator of acute oxygenation) and **Amniotic Fluid Index** (indicator of long-term placental function). * **Sequence of Loss:** In fetal hypoxia, the first sign to disappear is **NST reactivity**, followed by fetal breathing. The last to disappear is fetal tone. * **Scoring:** A score of 8–10 is normal; 4–6 is equivocal (may require delivery if at term); 0–2 is strongly suggestive of fetal asphyxia and mandates immediate delivery.

Q: Which teratogen is known to cause deafness?

Isotretinoin. **Explanation:** **Isotretinoin (Option A)** is a potent teratogen and a derivative of Vitamin A. It is associated with **Retinoic Acid Embryopathy**, which occurs due to the disruption of cranial neural crest cell migration. This leads to a specific constellation of defects, most notably **craniofacial malformations** including microtia (small ears), anotia (absent ears), and **congenital deafness** (due to stenosis of the external auditory canal or middle ear ossicle defects). It also causes CNS anomalies and conotruncal heart defects. **Analysis of Incorrect Options:** * **Chloroquine (Option B):** While some older literature suggested potential ototoxicity, it is generally considered safe in pregnancy for malaria prophylaxis and is not a classic cause of congenital deafness compared to Isotretinoin or Aminoglycosides. * **Alcohol (Option C):** Causes **Fetal Alcohol Syndrome (FAS)**, characterized by growth restriction, intellectual disability, and smooth philtrum/thin upper lip. While hearing issues can occur, they are not the hallmark feature. * **Warfarin (Option D):** Causes **Fetal Warfarin Syndrome**, characterized by **nasal hypoplasia**, stippled epiphyses (chondrodysplasia punctata), and optic atrophy, but not typically deafness. **NEET-PG High-Yield Pearls:** * **Aminoglycosides (e.g., Streptomycin/Kanamycin):** These are the most common pharmacological cause of **CN VIII damage** and permanent sensorineural deafness in the fetus. * **Congenital Rubella Syndrome:** The classic triad is **Deafness** (most common), Cataracts, and PDA ("Salt and pepper" retinopathy is also seen). * **Isotretinoin Rule:** A female patient must have two negative pregnancy tests before starting therapy and use two forms of contraception during treatment.

Q: Which of the following is NOT associated with teenage pregnancy?

Post-dated pregnancy is more common. **Explanation:** Teenage pregnancy (defined as pregnancy in girls aged 10–19) is considered a high-risk condition due to both biological immaturity and socio-economic factors. **Why "Post-dated pregnancy" is the correct answer:** Teenage pregnancies are significantly more associated with **Preterm Labor** (delivery before 37 weeks) rather than post-dated pregnancy. This is attributed to factors such as an immature uterine blood supply, a developing cervix, and a higher prevalence of genitourinary infections. Therefore, post-dated pregnancy is **not** a characteristic feature of teenage gestation. **Analysis of Incorrect Options:** * **Cesarean section is more common:** While some studies show varying rates, the incidence of C-sections is generally higher in teenagers due to **Cephalopelvic Disproportion (CPD)**. This occurs because the maternal bony pelvis may not be fully developed or fused, making it too small for the fetal head. * **Eclampsia is more common:** Young age (nulliparity) is a major risk factor for Hypertensive Disorders of Pregnancy. Teenagers have a significantly higher predisposition to **Pre-eclampsia and Eclampsia** compared to women in their 20s. * **Maternal mortality rate is higher:** The MMR is elevated in this group due to the higher frequency of complications like obstructed labor (CPD), eclampsia, and unsafe abortions, combined with late booking or poor antenatal care. **High-Yield Clinical Pearls for NEET-PG:** * **Most common complication:** Anemia (Iron deficiency). * **Fetal outcomes:** Higher risk of Low Birth Weight (LBW) and Intrauterine Growth Restriction (IUGR). * **Psychosocial:** Increased risk of postpartum depression and repeat pregnancy within two years. * **Key takeaway:** If a question asks for the "most common" obstetric complication in teens, think **Anemia** or **Pre-eclampsia**. If it asks for the "least likely" timing, think **Post-dated**.

Q: Which one of the following congenital malformations of the fetus can be diagnosed in the first trimester by ultrasound?

Anencephaly. **Explanation:** The correct answer is **Anencephaly**. **1. Why Anencephaly is the correct answer:** Anencephaly is a lethal neural tube defect characterized by the absence of the cranial vault (acrania) and cerebral hemispheres. With high-resolution transvaginal sonography (TVS), it can be reliably diagnosed in the late first trimester (11–14 weeks). The hallmark ultrasound findings are the **"Mickey Mouse sign"** (the appearance of preserved facial structures and orbits without a calvarium) and the **"Frog-eye appearance"** in the coronal plane. By 11 weeks, ossification of the skull should be complete; its absence confirms the diagnosis. **2. Why the other options are incorrect:** * **Inencephaly:** While a severe neural tube defect involving extreme retroflexion of the head, it is much rarer than anencephaly and often requires second-trimester imaging for a definitive diagnosis of the spinal involvement. * **Microcephaly:** This is a diagnosis of "growth" rather than "structure." It is typically diagnosed in the late second or third trimester because the head circumference must fall significantly below the mean (usually >3 SD) over time. * **Holoprosencephaly:** Although severe alobar forms can sometimes be suspected in the first trimester, it is traditionally a second-trimester diagnosis when the development of the midline structures (thalamus, falx cerebri) can be clearly assessed. **Clinical Pearls for NEET-PG:** * **Acrania-Anencephaly Sequence:** Acrania (absent skull with brain present) precedes anencephaly (brain degeneration due to exposure to amniotic fluid). * **Biochemical Marker:** Maternal Serum Alpha-Fetoprotein (MSAFP) is significantly **elevated** in open neural tube defects. * **Prevention:** 400 mcg of Folic acid daily (pre-conceptionally) reduces risk; 4 mg daily is required for women with a previous affected pregnancy.

Q: For fetal lung maturation, which of the following corticosteroids cannot be used?

Methylprednisolone. **Explanation:** The primary goal of administering corticosteroids in cases of anticipated preterm birth (24 to 34 weeks) is to accelerate fetal lung maturity and reduce the incidence of Respiratory Distress Syndrome (RDS), Intraventricular Hemorrhage (IVH), and Necrotizing Enterocolitis (NEC). **Why Methylprednisolone is the Correct Answer:** To be effective for fetal lung maturation, a corticosteroid must cross the placenta in its active form. **Methylprednisolone**, along with Hydrocortisone and Prednisolone, is extensively metabolized and inactivated by the placental enzyme **11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2)**. Consequently, these drugs do not reach the fetus in sufficient concentrations to induce surfactant production. **Analysis of Other Options:** * **Betamethasone (Option A) & Dexamethasone (Option B):** These are the only two recommended steroids for fetal lung maturity. They are fluorinated compounds that are poor substrates for 11β-HSD2, allowing them to cross the placenta easily and bind to fetal glucocorticoid receptors. * **Hydrocortisone (Option C):** Like Methylprednisolone, it is inactivated by the placenta and is not used for fetal lung maturation. However, in the context of this specific question format, Methylprednisolone is the classic "distractor" used in exams to differentiate between maternal and fetal indications. **High-Yield Clinical Pearls for NEET-PG:** * **Standard Regimens:** * Betamethasone: 12 mg IM, 2 doses, 24 hours apart (Drug of choice). * Dexamethasone: 6 mg IM, 4 doses, 12 hours apart. * **Timing:** Maximum benefit is seen if delivery occurs between 24 hours and 7 days after the first dose. * **Indication:** All women at risk of preterm delivery between **24 and 34 weeks** of gestation. * **Mechanism:** Steroids increase the synthesis of **Surfactant** (specifically Dipalmitoylphosphatidylcholine) by Type II pneumocytes.

Q: What is the normal pH range of amniotic fluid?

7.0 - 7.5. **Explanation:** The correct answer is **D (7.0 - 7.5)**. Amniotic fluid is physiologically **alkaline** or neutral. In the early stages of pregnancy, its composition is similar to maternal plasma (which has a pH of ~7.4). As the pregnancy progresses, fetal urine—which is slightly acidic—contributes significantly to the volume; however, the overall pH remains in the range of 7.0 to 7.5. **Why other options are incorrect:** * **Options A, B, and C (5.5 - 7.0):** These ranges are acidic. The normal vaginal environment is acidic (pH 3.8 - 4.5) due to the presence of *Lactobacillus* and lactic acid. Any pH measurement in these ranges would be more characteristic of vaginal secretions rather than amniotic fluid. **Clinical Pearls for NEET-PG:** 1. **Nitrazine Test:** This is a high-yield clinical application. When Premature Rupture of Membranes (PROM) is suspected, a Nitrazine paper test is performed. Because amniotic fluid is alkaline (7.0-7.5) and vaginal pH is acidic (4.0-4.5), the paper turns **blue** if amniotic fluid is present (positive test). 2. **Fern Test:** Along with the alkaline pH, the presence of sodium chloride in amniotic fluid creates a "ferning" pattern under a microscope, confirming ROM. 3. **Specific Gravity:** The specific gravity of amniotic fluid is low, approximately **1.008 to 1.010**. 4. **Osmolality:** It is initially isotonic but becomes hypotonic (approx. 250 mOsm/L) toward term as fetal kidneys mature.

Q: The amniotic fluid is completely replaced in every:

3 hours. **Explanation:** The turnover of amniotic fluid is a dynamic process involving constant production and resorption. While the volume of amniotic fluid increases throughout pregnancy (peaking at 34–36 weeks), the fluid itself is not static. It undergoes rapid exchange between the fetus, the placenta, and the maternal compartment. **Why 3 hours is correct:** Water in the amniotic fluid is replaced approximately every **3 hours**. This rapid turnover is achieved through several pathways: 1. **Fetal Swallowing:** The fetus swallows roughly 500–1000 ml/day. 2. **Fetal Urination:** The primary source of production in the second and third trimesters (approx. 800–1200 ml/day). 3. **Intramembranous Pathway:** Exchange across the fetal vessels on the placental surface (the most significant route for water and solute exchange). 4. **Transmembranous Pathway:** Exchange across the amnion and chorion into the maternal decidua. **Why other options are incorrect:** * **6, 9, and 12 hours:** These timeframes significantly underestimate the rate of fluid exchange. While electrolytes (like sodium) take longer to exchange (approx. 15 hours), the water component—which constitutes the bulk of the volume—is replaced much faster to maintain homeostasis and prevent acute fluctuations in pressure. **High-Yield Clinical Pearls for NEET-PG:** * **Peak Volume:** Amniotic fluid volume is maximum at **34–36 weeks** (approx. 800–1000 ml) and decreases thereafter to about 600 ml at term (40 weeks). * **Amniotic Fluid Index (AFI):** Measured via Phelan’s four-quadrant technique. Normal range: **5–24 cm**. * **Polyhydramnios:** AFI >25 cm or Single Deepest Pocket (SDP) >8 cm. Commonly associated with gestational diabetes and fetal GI atresia. * **Oligohydramnios:** AFI <5 cm or SDP <2 cm. Commonly associated with Renal agenesis (Potter sequence) and Placental insufficiency.

Q: A pregnant woman in her first trimester is diagnosed with an infection. Her baby is born with hydrocephalus. Which pathogen is the most likely cause of this infection?

Toxoplasma gondii. **Explanation:** The correct answer is **Toxoplasma gondii**. This protozoan infection is a classic member of the TORCH group. When a mother acquires a primary infection during pregnancy, the parasite can cross the placenta. The classic **Sabine’s Triad** of Congenital Toxoplasmosis includes: 1. **Hydrocephalus** (due to aqueductal stenosis) 2. **Intracranial calcifications** (typically diffuse/scattered) 3. **Chorioretinitis** **Why the other options are incorrect:** * **Herpes Simplex Virus (HSV):** Neonatal HSV is usually acquired during delivery (birth canal). It typically presents with skin-eye-mouth (SEM) vesicles, encephalitis, or disseminated multi-organ failure, rather than congenital hydrocephalus. * **Treponema pallidum (Syphilis):** Congenital syphilis is characterized by "Hutchinson’s Triad" (interstitial keratitis, sensorineural hearing loss, and notched incisors), along with hepatosplenomegaly, snuffles, and skeletal abnormalities (e.g., Sabre shin). * **Cytomegalovirus (CMV):** While CMV is the most common congenital infection and can cause ventriculomegaly, its hallmark finding is **periventricular calcifications** and microcephaly, rather than macrocephaly/hydrocephalus. **High-Yield Pearls for NEET-PG:** * **Toxoplasmosis:** Look for "Diffuse calcifications" and "Hydrocephalus." Treatment for the mother is **Spiramycin**; for the fetus/neonate, it is **Pyrimethamine and Sulfadiazine**. * **CMV:** Look for "Periventricular calcifications" and "Sensorineural hearing loss" (the most common sequela). * **Rule of Thumb:** If the head is large (hydrocephalus), think Toxoplasma. If the head is small (microcephaly), think CMV or Zika.

Question 1

All of the following are components of the biophysical profile except?

Accepted Answer

Fetal heart rate baseline

Answer

Amniotic fluid volume

Answer

Fetal breathing movements

Answer

Gross fetal body movements

Question 2

Which teratogen is known to cause deafness?

Accepted Answer

Isotretinoin

Answer

Chloroquine

Answer

Alcohol

Answer

Warfarin

Question 3

Which of the following is NOT associated with teenage pregnancy?

Accepted Answer

Post-dated pregnancy is more common

Answer

Cesarean section is more common

Answer

Eclampsia is more common

Answer

Maternal mortality rate is higher

Question 4

Which one of the following congenital malformations of the fetus can be diagnosed in the first trimester by ultrasound?

Accepted Answer

Anencephaly

Answer

Inencephaly

Answer

Microcephaly

Answer

Holoprosencephaly

Question 5

For fetal lung maturation, which of the following corticosteroids cannot be used?

Accepted Answer

Methylprednisolone

Answer

Betamethasone

Answer

Dexamethasone

Answer

Hydrocortisone

Question 6

What is the classical presentation of placenta previa?

Accepted Answer

Posterior

Answer

Answer

Central

Answer

Lateral

Question 7

What is the normal pH range of amniotic fluid?

Accepted Answer

7.0 - 7.5

Answer

5.5 - 6.0

Answer

6.0 - 6.5

Answer

6.5 - 7.0

Question 8

The amniotic fluid is completely replaced in every:

Accepted Answer

3 hours

Answer

6 hours

Answer

9 hours

Answer

12 hours

Question 9

A pregnant woman in her first trimester is diagnosed with an infection. Her baby is born with hydrocephalus. Which pathogen is the most likely cause of this infection?

Accepted Answer

Toxoplasma gondii

Answer

Herpes Simplex Virus (HSV)

Answer

Treponema pallidum

Answer

Cytomegalovirus (CMV)

Question 10

What is defined as heterotopic pregnancy?

Accepted Answer

Simultaneous extrauterine and intrauterine pregnancy

Answer

Pregnancy occurring in both fallopian tubes

Answer

Pregnancy occurring in both the ovary and fallopian tube

Answer

Pregnancy within the cervix

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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