Maternal-Fetal Medicine Practice Questions

Q: Following are the ultrasound parameters used in the diagnosis of intrauterine growth restriction except?

Ponderal index. ***Ponderal index*** - The **ponderal index** is a measure of proportionality (weight/length³) used to assess fetal body proportions and nutritional status, but it is calculated **after birth** using the newborn's weight and length. - It is **not an ultrasound parameter** used during prenatal diagnosis of intrauterine growth restriction (IUGR). - While it can identify asymmetric growth patterns postnatally, it has no role in prenatal IUGR assessment. *Abdominal circumference* - **Fetal abdominal circumference (AC)** is a key **biometric ultrasound parameter** that is essential in diagnosing IUGR. - It reflects fetal liver size and subcutaneous fat stores, making it the **most sensitive single parameter** for detecting IUGR. - Serial AC measurements below the 10th percentile or showing poor growth velocity are diagnostic criteria for IUGR. *Doppler velocimetry* - **Doppler velocimetry**, particularly of the **umbilical artery**, is crucial for assessing placental vascular resistance and diagnosing IUGR. - Abnormal findings include **increased pulsatility index (PI)**, **absent end-diastolic flow (AEDF)**, or **reversed end-diastolic flow (REDF)**. - These findings indicate placental insufficiency and help classify IUGR severity. *Increased diastolic velocity in middle cerebral artery* - **Increased diastolic velocity** in the middle cerebral artery (leading to **decreased PI/RI**) indicates the **brain-sparing effect** (cerebrovasodilation). - This is a fetal compensatory response to chronic hypoxemia in IUGR. - The **cerebroplacental ratio (CPR)** (umbilical artery PI / MCA PI) is a sensitive marker for adverse perinatal outcomes in IUGR.

Q: Estimation of fetal hemoglobin is done by?

Kleihauer-Betke Acid Elution Test (KB Test). ***Kleihauer-Betke Acid Elution Test (KB Test)*** - The **Kleihauer-Betke test** is a widely used laboratory method to quantify the amount of **fetal hemoglobin** in a maternal blood sample. - This test is crucial in situations involving **fetomaternal hemorrhage** for calculating the dose of Rh immunoglobulin. *Apt test* - The Apt test is used to determine if blood in a **neonate's stool or vomitus** is of fetal or maternal origin. - It differentiates between **fetal hemoglobin (HbF)**, which is resistant to alkaline denaturation, and adult hemoglobin (HbA), which is not. *Flow cytometry* - **Flow cytometry** is a powerful technique used for sorting and counting cells, detecting **biomarkers**, and analyzing cell characteristics. - While it can be adapted to detect cells containing fetal hemoglobin (e.g., in research settings), it is not the primary or standard method for estimating the **total amount of fetal hemoglobin** in a sample for clinical purposes. *Spectrophotometry* - **Spectrophotometry** measures the absorption or transmission of light through a sample at different wavelengths. - It is used in many biochemical assays but is not the specific or sensitive method for **quantifying fetal hemoglobin** due to the similar absorption spectra of different hemoglobin types.

Q: Most common cause of early abortion?

Genetic. ***Correct: Genetic*** - **Chromosomal abnormalities**, such as aneuploidy, are the most frequent cause of **spontaneous abortions**, especially early in pregnancy (accounting for **50-60% of first-trimester losses**). - These genetic errors often lead to **non-viable embryos**, resulting in early pregnancy loss. - Most common abnormalities include **trisomies** (especially trisomy 16), **monosomy X**, and **triploidy**. *Incorrect: Maternal* - While maternal factors like **diabetes** or **thyroid dysfunction** can contribute to abortion, they are less common causes of early abortion compared to genetic issues. - Systemic maternal health problems usually account for a smaller percentage of all miscarriages. *Incorrect: Immunologic* - **Autoimmune disorders** like **antiphospholipid syndrome** can cause recurrent pregnancy loss, but they are not the primary cause of the majority of early, sporadic abortions. - These are typically considered in cases of **recurrent miscarriages**, not usually the first or early spontaneous abortion. *Incorrect: Anatomic abnormalities* - **Uterine anomalies** (e.g., septate uterus) or **cervical incompetence** can lead to recurrent pregnancy loss, particularly in the later first or second trimester. - However, they are less frequently the cause of very early, isolated miscarriages compared to genetic factors.

Q: What is the most common cancer in pregnancy?

Breast carcinoma. ***Breast carcinoma*** - **Breast cancer** is the most frequently diagnosed cancer during pregnancy, affecting approximately 1 in 3,000 pregnant women - Its high prevalence is due to the rising maternal age and the general incidence of breast cancer in women of reproductive age - Pregnancy-associated breast cancer (PABC) often presents at more advanced stages due to delayed diagnosis *Melanoma* - While **melanoma** is a significant concern during pregnancy due to hormonal influences on tumor growth, it is not the most common cancer overall - It ranks among the top three most common malignancies but is less frequent than breast cancer *Gastric carcinoma* - **Gastric carcinoma** is rare in young women and thus has a very low incidence during pregnancy - Its presence usually indicates a more aggressive form of the disease *Thyroid carcinoma* - **Thyroid cancer** is one of the more common cancers diagnosed during pregnancy, often due to increased thyroid nodule detection, but it is less common than breast cancer - Most cases are **papillary thyroid carcinomas**, which often have a good prognosis despite pregnancy

Q: Monozygotic twin with one healthy baby born at term and one dead mummified fetus is suggestive of?

Fetus papyraceous. ***Fetus papyraceous*** - This term describes a **mummified fetus** that has been flattened and compressed due to the growth of a co-twin, often observed in **monochorionic twin pregnancies** where one twin dies in utero. - The presence of one healthy, term baby and one dead, mummified fetus is the classic presentation of **fetus papyraceous**. *Fetus acardiacus* - This is a rare anomaly where one twin, typically in a **monochorionic-monoamniotic pregnancy**, lacks a functional heart and other upper body structures, relying on the healthy twin's circulation. - An acardiac twin would present as an underdeveloped, often malformed structure, not a mummified, flattened fetus. *Hydatidiform mole* - A **hydatidiform mole** is an abnormal pregnancy characterized by the growth of many cysts (grape-like vesicles) within the uterus, resulting from an issue with fertilization, often leading to a non-viable pregnancy. - It does not involve the presence of a healthy twin alongside a dead mummified one. *Vanishing twin* - **Vanishing twin syndrome** occurs when one of two or more embryos or fetuses in a multiple pregnancy dies and is completely reabsorbed by the mother or the surviving twin. - While it involves the death of a twin, the reabsorption typically means there's no mummified fetus remaining by the time of birth; if a remnant is found, it's typically much smaller and not described as "papyraceous."

Q: Least common site of ectopic pregnancy in the fallopian tubes is?

Interstitium. ***Interstitium*** - The **interstitial portion** of the fallopian tube is the narrowest and thickest part, making it the least common site for an ectopic pregnancy within the tube itself. - While less frequent, interstitial pregnancies are associated with a **higher risk of rupture** and hemorrhage due to the surrounding myometrial tissue. *Ampulla* - The **ampulla** is the most common site of ectopic pregnancy in the fallopian tube, accounting for about 80% of all tubal ectopics. - Its wider diameter and convoluted lumen easily trap the fertilized egg. *Infundibulum* - The **infundibulum**, or fimbrial end, is a relatively common site for ectopic pregnancies after the ampulla, accounting for about 5% of cases. - Pregnancies here are often referred to as **fimbrial ectopic pregnancies**. *Isthmus* - The **isthmus** is the second most common site for tubal ectopic pregnancies, accounting for approximately 12% of cases. - This section is narrower than the ampulla but still more hospitable than the interstitial portion.

Q: Which is the most common presentation in twin pregnancy?

Vertex - vertex. ***Vertex - vertex*** - This is the most common presentation in **twin pregnancies**, occurring in approximately **40-45%** of cases. - Both twins are positioned head-down, which is the optimal presentation for a vaginal delivery. *Vertex - breech* - This presentation, where the first twin is head-down and the second twin is feet- or buttocks-first, occurs in about **30%** of twin pregnancies. - While relatively common, it is still less frequent than the vertex-vertex presentation. *Breech - breech* - This presentation, where both twins are positioned feet- or buttocks-first, is less common, occurring in less than **10%** of twin pregnancies. - It usually necessitates a **cesarean section** due to increased risks associated with vaginal breech delivery for both twins. *Vertex - Footling* - **Footling breech** is a specific type of breech presentation where one or both feet present first. - While a vertex presentation for the first twin and a footling breech for the second twin can occur, it's a less common overall presentation for twin pairs compared to vertex-vertex.

Q: What is the approximate fetal weight to placental weight ratio at 24 weeks of gestation?

2:1. ***2:1*** - The fetal weight to placental weight ratio at **24 weeks of gestation** varies across different references, with this ratio being cited in some older literature. - However, **current obstetric literature** suggests the ratio at 24 weeks is typically **higher (approximately 5:1 to 6:1)**, as the fetus (600-700g) significantly outweighs the placenta (100-120g) by this stage. - At 24 weeks, the fetus undergoes **rapid growth**, while placental growth rate has stabilized, leading to an increasing fetal-to-placental weight ratio. *1.5:1* - This ratio suggests the **fetus is only slightly heavier** than the placenta. - Such a ratio is typically observed **earlier in pregnancy (around 16-18 weeks)**, when placental mass is still relatively large compared to fetal mass. *3:1* - This ratio would indicate the fetus is **three times heavier** than the placenta. - While closer to physiologic values at 24 weeks, this still **underestimates** the typical fetal-to-placental weight ratio at this gestational age. *4:1* - This ratio suggests the fetus is **four times heavier** than the placenta. - This is **more consistent with mid-to-late second trimester** values and approaches the expected range, though current evidence suggests even higher ratios (5-6:1) at 24 weeks. **Note:** The fetal-to-placental weight ratio progressively increases throughout pregnancy, starting below 1:1 in early pregnancy and reaching 6-7:1 at term. Standard teaching suggests ratios of 5-6:1 at 24 weeks, though variation exists across references.

Q: What is the most common cause of death in babies with vasa previa?

Fetal exsanguination. ***Fetal exsanguination*** - In vasa previa, unprotected fetal blood vessels course directly over the **internal cervical os**. When the membranes rupture, these vessels are at high risk of tearing, leading to **rapid fetal blood loss**. - This acute hemorrhage results in **fetal exsanguination**, causing severe **anemia**, **hypoxia**, and ultimately **death** if not immediately identified and managed. *Infection* - While infection can arise in obstetric complications, it is **not the primary or most common cause of death** specifically associated with vasa previa. - The immediate and life-threatening danger in vasa previa is **acute blood loss**, not microbial invasion. *Maternal exsanguination* - Vasa previa primarily involves **fetal blood vessels** in the membranes, not maternal uterine vessels. - Therefore, the blood loss that occurs is almost exclusively fetal, and **maternal exsanguination is not a direct complication** of vasa previa. *Both maternal and fetal exsanguination* - As explained, vasa previa specifically endangers the fetus due to the exposed **fetal blood vessels**. - While fetal exsanguination is the critical event, **maternal exsanguination does not occur** as a direct result of vasa previa.

Question 1

Following are the ultrasound parameters used in the diagnosis of intrauterine growth restriction except?

Accepted Answer

Ponderal index

Answer

Doppler velocimetry

Answer

Increased diastolic velocity in middle cerebral artery

Answer

Abdominal circumference

Question 2

Estimation of fetal hemoglobin is done by?

Accepted Answer

Kleihauer-Betke Acid Elution Test (KB Test)

Answer

Apt test

Answer

Flow cytometry

Answer

Spectrophotometry

Question 3

Most common cause of early abortion?

Accepted Answer

Genetic

Answer

Maternal

Answer

Immunologic

Answer

Anatomic abnormalities

Question 4

What is the most common cancer in pregnancy?

Accepted Answer

Breast carcinoma

Answer

Melanoma

Answer

Gastric carcinoma

Answer

Thyroid carcinoma

Question 5

Monozygotic twin with one healthy baby born at term and one dead mummified fetus is suggestive of?

Accepted Answer

Fetus papyraceous

Answer

Fetus acardiacus

Answer

Hydatidiform mole

Answer

Vanishing twin

Question 6

Least common site of ectopic pregnancy in the fallopian tubes is?

Accepted Answer

Interstitium

Answer

Ampulla

Answer

Infundibulum

Answer

Isthmus

Question 7

Which is the most common presentation in twin pregnancy?

Accepted Answer

Vertex - vertex

Answer

Vertex - breech

Answer

Breech - breech

Answer

Vertex - Footling

Question 8

What is the approximate fetal weight to placental weight ratio at 24 weeks of gestation?

Accepted Answer

2:1

Answer

1.5:1

Answer

3:1

Answer

4:1

Question 9

What is the recommended management for intrauterine hydronephrosis detected at 32-34 weeks of gestation?

Accepted Answer

Serial USG monitoring and evaluation for associated anomalies

Answer

Intrauterine drainage

Answer

Immediate delivery

Answer

Postnatal evaluation at 3 weeks

Question 10

What is the most common cause of death in babies with vasa previa?

Accepted Answer

Fetal exsanguination

Answer

Infection

Answer

Maternal exsanguination

Answer

Both maternal and fetal exsanguination

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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