Maternal-Fetal Medicine Practice Questions

Q: What is the most common congenital anomaly in a baby born to a mother with insulin-dependent diabetes mellitus (IDDM)?

Cardiovascular anomalies. **Explanation:** In pregnancies complicated by pre-gestational diabetes (IDDM), maternal hyperglycemia during the period of organogenesis (first 8 weeks) is teratogenic. **Why Cardiovascular Anomalies are Correct:** Congenital heart diseases (CHDs) are the **most common** category of malformations seen in infants of diabetic mothers (IDM). The most frequent specific cardiac defects include **Ventricular Septal Defect (VSD)** and Transposition of the Great Arteries (TGA). Additionally, these infants are at high risk for hypertrophic cardiomyopathy, specifically asymmetric septal hypertrophy. **Analysis of Incorrect Options:** * **Neural Tube Defects (NTDs):** While the risk of NTDs (like anencephaly or spina bifida) is significantly increased (10-fold) in diabetic pregnancies compared to the general population, they are statistically less frequent than cardiac anomalies. * **Gastrointestinal/Pulmonary Anomalies:** While conditions like duodenal atresia or small left colon syndrome can occur, they are much rarer than cardiovascular or neurological defects. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Anomaly:** Cardiovascular anomalies (VSD is the most common specific defect). * **Most Specific Anomaly:** **Caudal Regression Syndrome** (Sacral Agenesis) is the most pathognomonic/specific malformation for maternal diabetes, though it is rare. * **HbA1c Correlation:** The risk of anomalies is directly proportional to the periconceptional HbA1c levels. An HbA1c >10% is associated with a 20-25% risk of major malformations. * **Gestational Diabetes (GDM):** Unlike IDDM, GDM (developing after 24 weeks) does **not** increase the risk of congenital anomalies because organogenesis is already complete.

Q: What is the risk of recurrence of anencephaly in a subsequent pregnancy?

2%. **Explanation:** Anencephaly is a lethal Neural Tube Defect (NTD) resulting from the failure of the cephalic end of the neural tube to close during the 3rd and 4th weeks of development. Most NTDs follow a **multifactorial inheritance pattern**, involving a combination of genetic predisposition and environmental factors (primarily folic acid deficiency). **1. Why 2% is correct:** For a couple with one previously affected child with a neural tube defect (like anencephaly or spina bifida), the risk of recurrence in a subsequent pregnancy is approximately **2-3%**. In standard medical textbooks and high-yield NEET-PG resources, **2%** is the most frequently cited figure for a single prior occurrence. If two previous children are affected, the risk rises significantly to about 10%. **2. Analysis of incorrect options:** * **A (1%):** This is closer to the risk for certain other congenital anomalies but underestimates the recurrence risk for NTDs. * **C & D (3% & 4%):** While some literature suggests a range up to 3%, 2% is the standard "best" answer for single recurrence in competitive exams. 4% is statistically higher than the average risk after only one affected pregnancy. **High-Yield Clinical Pearls for NEET-PG:** * **Prevention:** To reduce recurrence risk, women with a history of a child with NTD should take **4 mg (4000 mcg)** of Folic Acid daily, starting at least 1 month before conception through the first trimester. * **Primary Prevention:** For low-risk women (no prior history), the dose is **0.4 mg (400 mcg)**. * **Diagnosis:** Elevated **Maternal Serum Alpha-Fetoprotein (MSAFP)** and "frog-eye appearance" on ultrasound are classic markers for anencephaly. * **Polyhydramnios:** Anencephaly is frequently associated with polyhydramnios due to the absence of the swallowing reflex in the fetus.

Q: Polyhydramnios is NOT seen with which of the following conditions?

Renal agenesis. **Explanation:** The volume of amniotic fluid is a dynamic balance between production and removal. From the second trimester onwards, **fetal urine** is the primary source of amniotic fluid, while **fetal swallowing** is the primary route of removal. **1. Why Renal Agenesis is the correct answer:** In **Renal Agenesis** (Potter’s Sequence), the fetal kidneys fail to develop. Consequently, there is no urine production. Since urine is the major contributor to the amniotic pool, its absence leads to **Oligohydramnios** (AFI < 5 cm), not polyhydramnios. This is a classic "must-know" association for PG exams. **2. Why the other options are associated with Polyhydramnios:** * **Anencephaly:** Polyhydramnios occurs due to two reasons: (a) failure of the swallowing reflex due to neural defects and (b) transudation of fluid from the exposed meninges into the amniotic cavity. * **Multiple Pregnancy:** Increased fetal urine output (especially in Twin-to-Twin Transfusion Syndrome where the recipient twin develops polyuria) leads to increased fluid volume. * **Breech Presentation:** While not a direct cause, there is a statistical association. Polyhydramnios causes an overdistended uterus and increased fetal mobility, preventing the head from engaging and thus increasing the incidence of malpresentations like breech. **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**. * **Most common cause:** Idiopathic (60%), followed by Maternal Diabetes. * **GI Association:** Any condition causing GI obstruction (e.g., Esophageal or Duodenal atresia) prevents swallowing, leading to polyhydramnios. * **Maternal Complication:** Increased risk of Abruptio Placentae due to sudden decompression of the uterus (e.g., during ROM).

Q: What does the CTG graph shown in the image indicate regarding fetal heart rate patterns?

A deceleration in the cardiotocography trace. ***A deceleration in the cardiotocography trace*** - A **deceleration** represents a transient fall in **fetal heart rate (FHR)** below the baseline, indicating potential **fetal hypoxia** or **uteroplacental insufficiency**. - Decelerations are classified as **early**, **late**, or **variable** based on their timing relative to **uterine contractions** and require immediate evaluation. *An acceleration in the cardiotocography trace* - **Accelerations** are transient increases in FHR above baseline, typically indicating **fetal well-being** and adequate **oxygenation**. - They are considered **reassuring signs** on CTG monitoring, not concerning patterns requiring intervention. *Insufficient information to determine fetal well-being* - CTG provides continuous monitoring of **fetal heart rate** and **uterine activity**, offering valuable information about fetal status. - Modern CTG technology provides sufficient data to assess **fetal well-being** through pattern recognition and trend analysis. *A normal cardiotocography tracing* - A **normal CTG** shows baseline FHR between **110-160 bpm** with moderate **variability** and **accelerations** present. - Normal tracings are **reassuring** and do not indicate pathological fetal heart rate patterns requiring intervention.

Q: Which of the following is a risk factor for pre-eclampsia?

Primigravida. **Explanation:** Pre-eclampsia is a multisystem disorder characterized by new-onset hypertension (≥140/90 mmHg) and proteinuria (or end-organ dysfunction) after 20 weeks of gestation. **Why Primigravida is Correct:** Primigravida (nulliparity) is a well-established major risk factor for pre-eclampsia. The underlying pathophysiology involves **defective trophoblastic invasion** of the spiral arteries. In a first pregnancy, the maternal immune system has not been previously exposed to paternal antigens, leading to an altered immune response that contributes to placental ischemia and subsequent endothelial dysfunction. **Analysis of Incorrect Options:** * **Thin build:** Obesity (BMI >30) is a significant risk factor, not a thin build. Adiposity promotes a pro-inflammatory state and insulin resistance, both of which exacerbate endothelial damage. * **Smoking:** Paradoxically, smoking is associated with a **reduced risk** of pre-eclampsia. It is hypothesized that nicotine or carbon monoxide may inhibit the release of anti-angiogenic factors (like sFlt-1), though smoking is still discouraged due to risks of IUGR and abruption. * **Placenta previa:** There is no direct causal link between placenta previa and pre-eclampsia. However, **Placental Abruption** is a known complication of pre-eclampsia. **High-Yield Clinical Pearls for NEET-PG:** * **Highest Risk Factor:** A prior history of pre-eclampsia is the strongest predictor for recurrence. * **Other Risk Factors:** Multiple pregnancy (increased placental mass), Maternal age (>40 or <18), Chronic hypertension, Diabetes Mellitus, and Antiphospholipid Syndrome (APLA). * **Prophylaxis:** Low-dose Aspirin (75–150 mg) started before 16 weeks of gestation is recommended for high-risk women. * **Definitive Treatment:** Delivery of the fetus and placenta.

Q: Anencephaly is associated with which of the following factors?

All of these. Anencephaly is a lethal neural tube defect characterized by the absence of the major portion of the brain, skull, and scalp. It is associated with several obstetric complications that make "All of these" the correct answer. **Explanation of Factors:** 1. **Hydramnios (Polyhydramnios):** This is the most common association. It occurs because the fetus lacks the **swallowing reflex** due to the absence of higher cerebral centers and the exposure of the cerebrovasculosa to the amniotic fluid (transudation). 2. **Postmaturity:** Anencephaly often leads to prolonged pregnancy (post-term). This is due to the **absence of the fetal pituitary-adrenal axis**. The lack of fetal cortisol, which is essential for the initiation of labor, results in a failure to trigger the birthing process. 3. **Prematurity:** Conversely, prematurity is also common. This is usually **iatrogenic** (due to induction of labor once the anomaly is diagnosed) or spontaneous due to **uterine overdistension** caused by the associated polyhydramnios. **Clinical Pearls for NEET-PG:** * **Screening:** Elevated **Alpha-fetoprotein (AFP)** in maternal serum and amniotic fluid is a key marker. * **Diagnosis:** Ultrasound is the gold standard; the "Frog-eye appearance" is a classic sign due to the absence of the cranial vault and prominent orbits. * **Prevention:** Periconceptional intake of **400 mcg of Folic Acid** (5 mg for high-risk cases) significantly reduces the risk of recurrence. * **Associated finding:** "Shoulder dystocia" can occur during delivery because the small head fails to dilate the cervix adequately for the broad shoulders.

Q: What is the incidence of chromosomal abnormality per 1000 live births?

5.6. **Explanation:** The incidence of chromosomal abnormalities in live births is a high-yield statistic in Maternal-Fetal Medicine. According to standard textbooks like **Williams Obstetrics**, the overall incidence of chromosomal abnormalities is approximately **5.6 per 1000 live births** (or roughly 1 in 180 live births). **Why 5.6 is Correct:** Chromosomal abnormalities are categorized into numerical (aneuploidy) and structural abnormalities. * **Autosomal Aneuploidies:** Trisomy 21 is the most common (1.2 per 1000), followed by Trisomy 18 and 13. * **Sex Chromosome Aneuploidies:** These occur in about 2-3 per 1000 births (e.g., Klinefelter syndrome, Turner syndrome). * **Structural Abnormalities:** Balanced and unbalanced translocations account for the remainder. When these categories are aggregated, the total reaches the established figure of **5.6/1000**. **Analysis of Incorrect Options:** * **1.6 and 3.6:** These values are too low and represent only specific subsets (e.g., 1.6 is closer to the incidence of Trisomy 21 alone in certain age demographics). * **7.6:** This value overestimates the incidence in live births. While chromosomal abnormalities are found in 50-60% of first-trimester spontaneous abortions, the majority do not survive to term, leading to a lower incidence at birth. **High-Yield Clinical Pearls for NEET-PG:** * **Most common chromosomal abnormality in live births:** Trisomy 21 (Down Syndrome). * **Most common chromosomal abnormality in first-trimester abortions:** Autosomal trisomy (overall), specifically **Trisomy 16**. * **Most common single chromosomal abnormality in spontaneous abortions:** Monosomy X (45,X - Turner Syndrome). * **Incidence in Stillbirths:** Approximately 6-12%, significantly higher than in live births.

Question 1

A 38-year-old pregnant woman presents with severe vaginal bleeding. Ultrasound confirms placenta previa. What is the characteristic site of implantation in placenta previa?

Accepted Answer

Lower part of the uterine body, overlapping the internal cervical os

Answer

Uterine (fallopian) tubes

Answer

Cervix

Answer

Mesentery of the abdominal wall

Question 2

Which of the following statements is true regarding umbilical artery Doppler?

Accepted Answer

Absence of end-diastolic flow is normal at term.

Answer

Changes in the flow velocity waveforms of the umbilical artery may be important in the management of high-risk pregnancies.

Answer

Maternal smoking decreases the S/D ratio.

Answer

Increased diastolic flow indicates a worse prognosis.

Question 3

What is the most common congenital anomaly in a baby born to a mother with insulin-dependent diabetes mellitus (IDDM)?

Accepted Answer

Cardiovascular anomalies

Answer

Neural tube defect

Answer

Gastrointestinal tract anomalies

Answer

Pulmonary anomalies

Question 4

What is the risk of recurrence of anencephaly in a subsequent pregnancy?

Accepted Answer

2%

Answer

1%

Answer

3%

Answer

4%

Question 5

Polyhydramnios is NOT seen with which of the following conditions?

Accepted Answer

Renal agenesis

Answer

Anencephaly

Answer

Multiple pregnancy

Answer

Breech presentation

Question 6

What does the CTG graph shown in the image indicate regarding fetal heart rate patterns?

Accepted Answer

A deceleration in the cardiotocography trace

Answer

An acceleration in the cardiotocography trace

Answer

Insufficient information to determine fetal well-being

Answer

A normal cardiotocography tracing

Question 7

Which of the following is seen in pregnancy with heart disease, which is not seen in normal pregnancy?

Accepted Answer

Distended neck veins

Answer

Exertional dyspnea

Answer

Pedal edema

Answer

Supine hypotension

Question 8

Which of the following is a risk factor for pre-eclampsia?

Accepted Answer

Primigravida

Answer

Thin build

Answer

Smoking

Answer

Placenta previa

Question 9

Anencephaly is associated with which of the following factors?

Accepted Answer

All of these

Answer

Hydramnios

Answer

Postmaturity

Answer

Prematurity

Question 10

What is the incidence of chromosomal abnormality per 1000 live births?

Accepted Answer

5.6

Answer

1.6

Answer

3.6

Answer

7.6

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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