Maternal-Fetal Medicine Practice Questions

Q: In an Rh-negative mother who has delivered an Rh-positive baby, prophylactic anti-D is indicated for:

If the Indirect Coomb's test (ICT) is negative. ***If the Indirect Coomb's test (ICT) is negative*** - Prophylactic anti-D immunoglobulin works by **preventing active antibody production** in the mother when her immune system is first exposed to Rh-positive fetal red blood cells. - A **negative Indirect Coombs' test** indicates that the mother has not yet been sensitized and does not have pre-existing anti-Rh antibodies, making her an ideal candidate for prophylaxis. - This is the **key requirement** for anti-D administration to be effective. *If the Indirect Coomb's test (ICT) is positive (indicating sensitization)* - If the ICT is positive, it means the mother has already been **sensitized** and has produced antibodies against Rh-positive blood. - In this scenario, administering anti-D immunoglobulin would be ineffective as the **immune response has already occurred**. *If the Indirect Coomb's test (ICT) is positive with rising antibody titres* - A positive ICT with rising titers signifies that the mother is not only sensitized but also actively producing a **stronger immune response** against Rh-positive blood. - Anti-D immunoglobulin is a **preventative measure**, not a treatment for an active immune response, and would not be beneficial in this case. *As a routine procedure for all Rh-negative mothers regardless of sensitization status* - While anti-D is routinely recommended for non-sensitized Rh-negative mothers, it **must not be given without confirming negative sensitization status**. - Administering anti-D to already sensitized mothers (positive ICT) is ineffective and wasteful, as the immune response has already been established. - The ICT must be performed to **exclude prior sensitization** before prophylactic anti-D is given.

Q: Which of the following is a known cause of breech presentation?

Hydramnios. ***Hydramnios*** - **Excessive amniotic fluid** (polyhydramnios) increases the space available for fetal movement, preventing the fetus from settling into a stable cephalic position - This allows **increased fetal mobility** and is a well-recognized cause of **malpresentation including breech presentation** - The lack of normal space constraints means the fetus can freely move and fail to engage in vertex position *Septate uterus* - **Uterine anomalies** including septate uterus can restrict the intrauterine space and are recognized causes of breech presentation - However, they are **less common** than other causes and may also lead to recurrent pregnancy loss or preterm delivery - While a valid cause, it's not as frequently encountered as polyhydramnios in clinical practice *Hydrocephalus* - **Fetal hydrocephalus** with enlarged head can prevent normal engagement of the fetal head in the maternal pelvis - This can lead to malpresentation, though the mechanism is more about **disproportion** preventing cephalic engagement rather than causing breech directly - It's a recognized but less common fetal factor compared to other causes *Uterine fibroids* - **Large uterine fibroids**, particularly those in the lower uterine segment, can obstruct fetal descent and cause malpresentation - They alter uterine cavity shape and can prevent normal version to cephalic presentation - However, they are a **less frequent** direct cause compared to conditions like polyhydramnios or oligohydramnios

Q: What are the potential complications in subsequent pregnancies for a woman with a history of gestational trophoblastic disease?

Increased risk of recurrent GTD and pregnancy complications. ***Increased risk of recurrent GTD and pregnancy complications*** - A history of **gestational trophoblastic disease (GTD)** significantly increases the risk of recurrence in subsequent pregnancies, emphasizing the need for close monitoring. - There is also an elevated risk of other **adverse pregnancy outcomes**, including **preterm birth** and **preeclampsia**, following a GTD history. *Neural tube defects* - **Neural tube defects** are congenital anomalies primarily associated with **folate deficiency** and genetic factors, not a prior history of GTD. - They involve incomplete closure of the neural tube during embryonic development, unrelated to trophoblastic tissue. *Cardiac defects* - **Congenital cardiac defects** are multifactorial, linked to genetic predisposition, maternal conditions like **diabetes**, and certain exposures, but not a history of GTD. - They result from abnormal heart development in the early stages of pregnancy. *Skeletal defects* - **Skeletal defects** can be hereditary or related to maternal infections (e.g., rubella), drug exposure (e.g., thalidomide), or specific genetic syndromes, not GTD. - These malformations occur during fetal bone and limb development.

Q: The weight of the placenta at term is

500 gm. ***Correct: 500 gm*** - The average weight of a full-term placenta is approximately **500 grams (1 pound)**. - This weight is typically about **one-sixth of the baby's weight** at term. - Normal range is approximately **450-650 grams**. *Incorrect: 250 gm* - A placenta weighing 250 grams at term would be considered **abnormally small** and could indicate **placental insufficiency** or other complications. - A smaller placenta may not be able to adequately support fetal growth and development. *Incorrect: 750 gm* - A placenta weighing 750 grams at term would be considered **abnormally large**, potentially indicating conditions like **maternal diabetes**, **fetal hydrops**, or **placental edema**. - This represents a significantly enlarged placenta beyond the normal range. *Incorrect: 1000 gm* - A placenta weighing 1000 grams (1 kg) at term would be considered **markedly enlarged**, potentially indicating severe conditions like **maternal diabetes**, **fetal hydrops**, **infection**, or **placentomegaly**. - While larger than average, such weights can occur in pathological pregnancies but are far from the normal 500g in a healthy pregnancy.

Q: Which of the following statements regarding cholestasis in pregnancy is false?

Mild jaundice occurs in majority of patients. ***Mild jaundice occurs in majority of patients*** - This statement is **false** because while **pruritus** is a hallmark symptom of **intrahepatic cholestasis of pregnancy (ICP)**, **jaundice** is relatively uncommon, occurring in only **10-25%** of patients, typically those with more severe disease. - The primary clinical manifestation is intense itching, often without visible signs of jaundice. *Recurs in subsequent pregnancy* - **Cholestasis in pregnancy** has a **high recurrence rate**, estimated to be between **45% to 90%** in subsequent pregnancies. - This tendency for recurrence highlights a possible genetic predisposition or hormonal sensitivity. *Ursodeoxycholic acid relieves pruritus* - **Ursodeoxycholic acid (UDCA)** is the **first-line treatment** for cholestasis in pregnancy and is effective in improving biochemical markers and relieving **pruritus**. - It works by altering the bile acid composition, making them less toxic and facilitating their excretion. *Pruritus is the most common symptom of cholestasis in pregnancy* - **Pruritus** is indeed the **most common and prominent symptom** of ICP, occurring in virtually all patients. - Some patients may also experience **fatigue**, **nausea**, **dark urine**, **pale stools**, or **steatorrhea**, although these are less common. - It is also associated with fetal risks such as **preterm birth**, **stillbirth**, and **fetal distress**, which are important complications of the condition.

Q: Which of the following tests on amniotic fluid is most useful in distinguishing between open neural tube defects and ventral wall defects in a fetus?

Acetylcholinesterase. ***Acetylcholinesterase*** - **Acetylcholinesterase (AChE)** is highly specific to neural tissue and its presence in amniotic fluid, combined with elevated AFP, is highly indicative of an **open neural tube defect (NTD)**. - While AFP is elevated in both NTDs and ventral wall defects, **AChE** helps differentiate by confirming neural tissue exposure. *Carcinoembryonic antigen* - **Carcinoembryonic antigen (CEA)** is a tumor marker primarily used in the diagnosis and monitoring of certain cancers, particularly colorectal cancer. - It has no established role in the prenatal diagnosis or differentiation of neural tube defects or ventral wall defects. *Sphingomyelin* - **Sphingomyelin** is a component of pulmonary surfactant and is measured to assess fetal lung maturity, usually in conjunction with lecithin as the **L/S ratio**. - This test is not used for the diagnosis or differentiation of structural birth defects like neural tube defects or ventral wall defects. *Alpha-fetoprotein* - **Alpha-fetoprotein (AFP)** is elevated in maternal serum and amniotic fluid in both **open neural tube defects** and **ventral wall defects** (e.g., gastroschisis, omphalocele). - While useful for screening, **AFP alone cannot distinguish** between these two conditions, as it is non-specific for the type of open defect.

Q: Alpha-fetoproteins are not increased in which of the following conditions?

Post maturity. ***Correct: Post maturity*** - In **post-maturity**, the fetus continues to develop past the expected due date (>42 weeks) - **Alpha-fetoprotein (AFP)** levels are **not elevated** in post-term pregnancies - AFP levels may actually decline as pregnancy progresses beyond term - Post-maturity is associated with placental insufficiency, not AFP elevation *Incorrect: Spina bifida* - **Spina bifida** is an **open neural tube defect** where the spinal cord is exposed - Leads to direct leakage of AFP into the amniotic fluid and maternal serum - Causes **significantly elevated AFP levels** (typically >2.5 MoM) *Incorrect: Omphalocele* - **Omphalocele** is an **abdominal wall defect** where abdominal organs herniate through the umbilicus - Covered by a membrane, but still allows AFP leakage - Associated with **elevated maternal serum AFP levels** - AFP elevation is less pronounced than with neural tube defects *Incorrect: Anencephaly* - **Anencephaly** is a severe **open neural tube defect** with absence of major portions of the brain and skull - Results in direct exposure of neural tissue to amniotic fluid - One of the **most common causes of markedly elevated AFP** (often >3-4 MoM) - Almost always detectable by elevated maternal serum AFP screening

Q: Sonography of a term multigravida shows an amniotic fluid index of 3 cm. The fetus may have which condition?

Renal agenesis. ***Renal agenesis*** - An **Amniotic Fluid Index (AFI)** of 3 cm indicates **oligohydramnios**, which is a severely reduced amount of amniotic fluid. - **Fetal urine production** is a major source of amniotic fluid in the second half of pregnancy, and conditions like renal agenesis or severe renal obstruction prevent urine formation, leading to oligohydramnios. *Esophageal atresia* - This condition is associated with **polyhydramnios** (excess amniotic fluid) because the fetus cannot swallow the amniotic fluid. - Oligohydramnios is typically not seen with esophageal atresia. *Spina bifida* - **Neural tube defects** like spina bifida are not typically associated with oligohydramnios. - They are sometimes linked to **polyhydramnios** if there is impaired fetal swallowing due to brainstem involvement, or normal amniotic fluid levels. *Chorioangioma of the placenta* - A **chorioangioma** is a benign placental tumor that can rarely cause **polyhydramnios** due to increased blood flow to the tumor, leading to increased transudation of fluid. - It would not lead to **oligohydramnios**.

Question 1

Which of the following statements regarding the umbilical cord is true?

Accepted Answer

Observation of a single umbilical artery is associated with additional anomalies

Answer

Two arteries and two veins

Answer

One artery and two veins

Answer

Observation of a single umbilical vein is associated with additional anomalies

Question 2

In an Rh-negative mother who has delivered an Rh-positive baby, prophylactic anti-D is indicated for:

Accepted Answer

If the Indirect Coomb's test (ICT) is negative

Answer

If the Indirect Coomb's test (ICT) is positive (indicating sensitization)

Answer

If the Indirect Coomb's test (ICT) is positive with rising antibody titres

Answer

As a routine procedure for all Rh-negative mothers regardless of sensitization status

Question 3

Which of the following is a known cause of breech presentation?

Accepted Answer

Hydramnios

Answer

Septate uterus

Answer

Hydrocephalus

Answer

Uterine fibroids

Question 4

What are the potential complications in subsequent pregnancies for a woman with a history of gestational trophoblastic disease?

Accepted Answer

Increased risk of recurrent GTD and pregnancy complications

Answer

Neural tube defects

Answer

Skeletal defects

Answer

Cardiac defects

Question 5

The weight of the placenta at term is

Accepted Answer

500 gm

Answer

250 gm

Answer

1000 gm

Answer

750 gm

Question 6

Which of the following statements regarding cholestasis in pregnancy is false?

Accepted Answer

Mild jaundice occurs in majority of patients

Answer

Ursodeoxycholic acid relieves pruritus

Answer

Recurs in subsequent pregnancy

Answer

Pruritus is the most common symptom of cholestasis in pregnancy

Question 7

Which of the following tests on amniotic fluid is most useful in distinguishing between open neural tube defects and ventral wall defects in a fetus?

Accepted Answer

Acetylcholinesterase

Answer

Carcinoembryonic antigen

Answer

Alpha-fetoprotein

Answer

Sphingomyelin

Question 8

A 26-year-old gravida 3 woman has a history of gestational diabetes and a delivery of two previous infants at term that were greater than 4000 grams, each of whom had severe hypoglycemia. Which of the following maneuvers is least likely to reduce the chance of the next child's having hypoglycemia?

Accepted Answer

Maternal intravenous loading with 10% glucose beginning 2 to 4 h prior to the expected time of delivery

Answer

Careful glucose monitoring of the infant

Answer

Careful control of the maternal blood glucose levels during pregnancy

Answer

Early feedings of the infant

Question 9

Alpha-fetoproteins are not increased in which of the following conditions?

Accepted Answer

Post maturity

Answer

Omphalocele

Answer

Anencephaly

Answer

Spina bifida

Question 10

Sonography of a term multigravida shows an amniotic fluid index of 3 cm. The fetus may have which condition?

Accepted Answer

Renal agenesis

Answer

Esophageal atresia

Answer

Spina bifida

Answer

Chorioangioma of the placenta

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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