Maternal-Fetal Medicine — MCQs
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What is the condition characterized by fetal blood vessels crossing or running near the cervical os?
Fetal nuchal translucency is useful in detecting:
A 32-year-old pregnant woman presents with mild bleeding and pain. On examination, the uterus is tender, and fetal heart sounds are absent. What is the most likely diagnosis?
A pregnant woman exposed to a teratogenic drug during the first trimester is most likely to result in which of the following defects?
Maternal-Fetal Medicine Indian Medical PG Practice Questions and MCQs
Question 1361: What is the condition characterized by fetal blood vessels crossing or running near the cervical os?
- A. Marginal placenta
- B. Velamentous placenta
- C. Battledore placenta
- D. Vasa previa (Correct Answer)
Explanation: ***Vasa previa*** - This condition involves **fetal blood vessels** unprotected by placental tissue or umbilical cord, lying over or in close proximity to the **internal cervical os**. - It carries a high risk of **fetal exsanguination** and death if these vessels rupture during labor when the membranes rupture. *Marginal placenta* - This term, also known as **placenta previa marginalis**, refers to a placenta that touches the edge of the internal cervical os but does not cover it. - While it can cause bleeding, it does not involve **fetal vessels** directly crossing the os in the same dangerous manner as vasa previa. *Velamentous placenta* - In a **velamentous umbilical cord insertion**, the umbilical cord inserts into the **chorioamniotic membranes** rather than directly into the placental mass. - The umbilical vessels then travel through the membranes to reach the placenta, which can make them vulnerable to compression, but this condition is distinct from **vasa previa** unless these exposed vessels specifically cross the cervical os. *Battledore placenta* - Also known as **marginal cord insertion**, this describes an umbilical cord that inserts directly into the **edge or margin of the placenta**. - While it may be associated with certain fetal growth restrictions, it does not typically involve **fetal vessels** exposed or crossing the internal cervical os.
Question 1362: Fetal nuchal translucency is useful in detecting:
- A. Fetal infection
- B. Down syndrome (Correct Answer)
- C. Anencephaly
- D. Hydrops fetalis
Explanation: ***Down syndrome*** - An increased **nuchal translucency (NT)** measurement, indicating excess fluid at the back of the fetal neck, is a key soft marker for **Down syndrome** (Trisomy 21). - NT screening, performed between **11 and 14 weeks of gestation**, is the **primary and most important clinical application** of nuchal translucency measurement in first-trimester screening for chromosomal abnormalities. - This is the **best answer** as NT screening is specifically established and routinely used for detecting aneuploidies, particularly Down syndrome. *Fetal infection* - While some fetal infections can cause edema, **increased nuchal translucency** is not a primary or direct marker used for diagnosing or screening for fetal infections. - Fetal infections are typically detected through specific **serological tests**, **amniocentesis**, or other ultrasound findings like **hydrops**, **microcephaly**, or **intracranial calcifications**. *Anencephaly* - **Anencephaly** is a severe **neural tube defect** characterized by the absence of a major portion of the brain and skull. - It is typically diagnosed through **cranium abnormalities** on ultrasound, not primarily by nuchal translucency measurements. - Anencephaly is usually detected in the **second trimester** when cranial anatomy is better visualized. *Hydrops fetalis* - While increased NT **can be associated** with hydrops fetalis and may indicate impending hydrops or underlying conditions that lead to hydrops (such as cardiac anomalies), this is **not the primary clinical indication** for NT measurement. - **Hydrops fetalis** involves generalized edema and fluid accumulation in **multiple fetal compartments** (ascites, pleural effusions, pericardial effusions, skin edema), whereas NT is a **localized** finding at the nuchal area. - The **primary and established use** of NT screening is for **chromosomal abnormalities**, particularly Down syndrome, making that the best answer in this clinical context.
Question 1363: A 32-year-old pregnant woman presents with mild bleeding and pain. On examination, the uterus is tender, and fetal heart sounds are absent. What is the most likely diagnosis?
- A. Abruptio placenta (Correct Answer)
- B. Uterine rupture
- C. Ectopic pregnancy
- D. Placenta previa
Explanation: ***Abruptio placenta*** - This condition involves the **premature detachment of the placenta** from the uterine wall, leading to bleeding and severe abdominal pain due to uterine contractions and irritation. - The **tender uterus** is a characteristic finding, often described as a "woody hard" uterus in severe cases. - The absence of fetal heart sounds suggests **fetal demise**, which is a common and severe complication of placental abruption due to oxygen deprivation. *Uterine rupture* - **Uterine rupture** can present with abdominal pain, vaginal bleeding, and loss of fetal heart tones, making it an important differential. - However, it typically occurs during **active labor**, especially in women with previous cesarean sections or uterine surgery. - The presentation usually includes **sudden severe pain**, loss of uterine contractions, and the fetus may be palpable abdominally if completely extruded. *Ectopic pregnancy* - This occurs when the **fertilized egg implants outside the uterus**, most commonly in the fallopian tube. - Symptoms typically appear much earlier in pregnancy **(first trimester)** and the pain is usually localized, often presenting with a smaller, non-tender uterus. - Not consistent with the clinical picture of an obviously pregnant uterus. *Placenta previa* - **Placenta previa** is characterized by the placenta covering the cervical opening, leading to **painless vaginal bleeding**, often bright red. - The uterus is typically **soft and non-tender**, in contrast to the tender uterus described in the case. - This is the key differentiating feature from placental abruption.
Question 1364: A pregnant woman exposed to a teratogenic drug during the first trimester is most likely to result in which of the following defects?
- A. Neural tube defects (Correct Answer)
- B. Hypospadias
- C. Cleft palate
- D. Polydactyly
Explanation: ***Neural tube defects*** - The **neural tube** forms during the **third to fourth week of gestation**, representing the **earliest critical period** of organogenesis in the first trimester. Exposure to teratogens during this period can disrupt its closure. - Examples include **spina bifida** and **anencephaly**, which are severe structural malformations. - Because this is the **earliest organogenesis event**, it is the **most vulnerable** to teratogenic exposure in the first trimester, making neural tube defects the **most likely** outcome when timing is unspecified. - Classic teratogens include **valproic acid**, **carbamazepine**, and **folic acid deficiency**. *Cleft palate* - The palate develops between the **6th and 12th weeks of gestation**, which is also within the first trimester. - This is a **common teratogenic defect** associated with medications like **phenytoin**, **corticosteroids**, and **retinoids**. - However, palate formation occurs **later than neural tube closure**, making it a secondary consideration when the question asks for the "most likely" first-trimester defect. *Hypospadias* - This condition involves incomplete fusion of the **urethral folds**, which occurs during the **9th to 12th weeks of gestation** (late first to early second trimester). - While teratogens can contribute, the critical period extends beyond the first trimester, and it is **less commonly** associated with classic first-trimester teratogen exposure compared to neural tube defects. *Polydactyly* - Characterized by **extra fingers or toes**, this condition most commonly results from **genetic mutations** rather than direct teratogenic exposure. - Limb development occurs during the **fifth to ninth weeks of gestation**; while teratogens can affect limb development (e.g., thalidomide causing limb reduction), polydactyly itself is **rarely** directly linked to teratogen exposure.
Practice by Chapter
Fetal Assessment Techniques
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Hypertensive Disorders in Pregnancy
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Intrauterine Growth Restriction
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Multiple Gestation
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Rh Isoimmunization and Other Blood Group Incompatibilities
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Intrauterine Fetal Therapy
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Prenatal Diagnosis and Genetic Counseling
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Placental Abnormalities
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Preterm Labor and Delivery
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Management of Medical Disorders in Pregnancy
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