Maternal-Fetal Medicine Practice Questions

Q: What is the condition characterized by fetal blood vessels crossing or running near the cervical os?

Vasa previa. ***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.

Q: 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?

Abruptio placenta. ***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.

Q: A pregnant woman exposed to a teratogenic drug during the first trimester is most likely to result in which of the following defects?

Neural tube defects. ***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.

Question 1

What is the condition characterized by fetal blood vessels crossing or running near the cervical os?

Accepted Answer

Vasa previa

Answer

Marginal placenta

Answer

Velamentous placenta

Answer

Battledore placenta

Question 2

Fetal nuchal translucency is useful in detecting:

Accepted Answer

Down syndrome

Answer

Fetal infection

Answer

Anencephaly

Answer

Hydrops fetalis

Question 3

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?

Accepted Answer

Abruptio placenta

Answer

Uterine rupture

Answer

Ectopic pregnancy

Answer

Placenta previa

Question 4

A pregnant woman exposed to a teratogenic drug during the first trimester is most likely to result in which of the following defects?

Accepted Answer

Neural tube defects

Answer

Hypospadias

Answer

Cleft palate

Answer

Polydactyly

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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