Maternal-Fetal Medicine Practice Questions

Q: In a case of suspected Rh incompatibility in a pregnant woman, what is the next step in the investigation?

Indirect Coomb's test. ***Indirect Coomb's test*** - The **indirect Coomb's test** (also known as the indirect antiglobulin test) identifies **Rh antibodies** in the mother's serum, indicating she has been sensitized to Rh-positive blood. - This test is crucial for determining if the mother is at risk of producing antibodies that could attack a subsequent Rh-positive fetus. *RhoGAM* - **RhoGAM** (Rh immunoglobulin) is a **preventive treatment** given to Rh-negative mothers, not a diagnostic test. - It works by neutralizing fetal Rh-positive red blood cells in the maternal circulation, preventing the mother's immune system from developing antibodies. *Direct Coomb's test* - The **direct Coomb's test** (or direct antiglobulin test) is performed on the **infant's blood** postnatal to detect antibodies already coating the infant's red blood cells. - This indicates that the infant's red blood cells have been attacked by maternal antibodies, suggesting hemolysis. *Detection of fetal cells in maternal circulation* - Detecting **fetal cells in maternal circulation** (e.g., using the Kleihauer-Betke test) is used to quantify the amount of **feto-maternal hemorrhage**. - This quantification helps determine the appropriate dose of RhoGAM needed after a potential exposure, such as trauma or delivery, but it doesn't diagnose the mother's sensitization status.

Q: Nonimmune hydrops fetalis is caused by which of the following?

Parvovirus B19. ***Parvovirus B19*** - **Parvovirus B19** infection in the fetus can lead to severe **anemia** due to its tropism for erythroid progenitor cells, which then causes **high-output cardiac failure** and subsequent **nonimmune hydrops fetalis**. - The anemia results in impaired oxygen delivery, leading to generalized edema and fluid accumulation in multiple fetal compartments, characteristic of hydrops fetalis. *Cytomegalovirus (CMV)* - While **CMV** is a common congenital infection and can cause significant fetal morbidity and mortality, it typically leads to symptoms like **microcephaly**, periventricular calcifications, and **sensorineural hearing loss**, rather than nonimmune hydrops fetalis as its primary presentation. - Though severe CMV can cause anemia and liver dysfunction, it is less commonly associated with the widespread edema and fluid accumulation seen in nonimmune hydrops compared to Parvovirus B19. *Herpes Simplex Virus (HSV)* - **HSV** infection in neonates is usually acquired during birth and can cause severe **skin lesions**, encephalitis, and disseminated disease, but it does not typically present as **nonimmune hydrops fetalis**. - Congenital HSV is very rare and symptoms when present are usually neurological or dermatological. *Human Immunodeficiency Virus (HIV)* - **HIV** infection in the fetus primarily results in **immunodeficiency** and increased susceptibility to opportunistic infections, often presenting with symptoms such as **failure to thrive**, recurrent infections, and developmental delays. - It is not a direct cause of **nonimmune hydrops fetalis**, which is characterized by widespread fluid accumulation due to circulatory or lymphatic issues.

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: Ectopic pregnancy typically lasts longer before rupture in which location?

Interstitial. ***Interstitial*** - An **interstitial ectopic pregnancy** occurs in the portion of the fallopian tube that passes through the **uterine muscular wall**, allowing for greater distention. - This anatomical location provides more space for the pregnancy to grow before rupture occurs, often leading to a later presentation and more catastrophic hemorrhage when rupture does happen. *Cervical* - A **cervical ectopic pregnancy** implants in the endocervical canal, an area not designed to support a growing pregnancy. - These pregnancies typically present with heavy bleeding early on and do not usually have a prolonged course before significant complications arise. *Isthmic* - **Isthmic ectopic pregnancies** occur in the narrowest part of the fallopian tube, which has a limited capacity for expansion. - Due to the small lumen and muscular wall, these pregnancies tend to rupture earlier, often within 6-8 weeks, and are associated with a high risk of hemorrhage. *Ampullary* - **Ampullary ectopic pregnancies** are the most common type, occurring in the widest part of the fallopian tube. - While they can grow to a larger size than isthmic pregnancies, the thin wall of the ampulla means they typically rupture earlier than interstitial pregnancies, usually by 8-10 weeks.

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.

Question 1

In a case of suspected Rh incompatibility in a pregnant woman, what is the next step in the investigation?

Accepted Answer

Indirect Coomb's test

Answer

RhoGAM

Answer

Detection of fetal cells in maternal circulation

Answer

Direct Coomb's test

Question 2

Nonimmune hydrops fetalis is caused by which of the following?

Accepted Answer

Parvovirus B19

Answer

Cytomegalovirus (CMV)

Answer

Herpes Simplex Virus (HSV)

Answer

Human Immunodeficiency Virus (HIV)

Question 3

A 24-year-old primigravida with HIV serology positive is in the antenatal outpatient department. Her CD4 count is 600 cells/μL, and her HIV-1 viral load is 2,680 copies/mL. Which of the following is the best method of reducing maternal-fetal transmission of HIV infection?

Accepted Answer

Triple antiretroviral therapy for the mother throughout pregnancy

Answer

Elective cesarean section

Answer

Pooled intravenous immunoglobulin G therapy for the infant

Answer

Nevirapine therapy for the infant after birth

Question 4

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 5

Ectopic pregnancy typically lasts longer before rupture in which location?

Accepted Answer

Interstitial

Answer

Isthmic

Answer

Ampullary

Answer

Cervical

Question 6

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

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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