Maternal-Fetal Medicine Practice Questions

Q: What is the critical value of the shock index that is considered abnormal in pregnancy?

0.9-1.1. ***0.9-1.1*** - A **shock index (heart rate/systolic blood pressure) of 0.9 or greater** is considered abnormal and a critical value in pregnant patients. - This elevated threshold indicates a significant risk of **hypovolemia and hemodynamic compromise**, which might be masked by the physiological changes of pregnancy. - Values ≥0.9 suggest that compensatory mechanisms are failing and require **immediate clinical intervention**. *0.5-0.7* - This range represents a **normal shock index for non-pregnant adults**. - Due to the **physiological hypervolemia and cardiovascular adaptations** of pregnancy, vital signs can remain deceptively stable even with significant blood loss, making this range inappropriately low for identifying shock in pregnant patients. *0.3-0.5* - A shock index within this range is considered **low** and generally indicative of a well-perfused state in non-pregnant individuals. - It does not reflect the **baseline physiological changes** seen in pregnancy and would miss critical hemodynamic compromise in obstetric emergencies. *0.7-0.9* - While this range may indicate mild elevation approaching abnormal values, it falls **below the established critical threshold of 0.9** for pregnancy. - The critical cutoff is specifically set at **≥0.9** to ensure **early detection and intervention** for maternal hemodynamic compromise before decompensation occurs.

Q: At what gestational age is transabdominal color Doppler sonography optimally performed to assess fetal well-being?

18-20 weeks. ***18-20 weeks*** - This gestational age is ideal for a **detailed anatomical survey** and assessing fetal well-being using **transabdominal color Doppler sonography**. - At this stage, fetal structures are well-developed, and the **fetus is large enough** for accurate assessment of blood flow in various vessels. *11-13 weeks* - This period is primarily for **nuchal translucency** screening and early structural assessment, but fetal vessels are generally too small for optimal Doppler flow studies. - While some early Doppler studies can be done, a comprehensive assessment of fetal well-being is usually not achieved. *Done before 10 weeks* - Before 10 weeks, the embryo/fetus is **too small** for a detailed anatomical survey or meaningful Doppler assessment of most vessels. - Doppler studies at this stage are usually limited to confirming viability via **heartbeat.** *5-7 weeks* - This is a very early stage of pregnancy where the primary goal of sonography is to confirm **intrauterine pregnancy**, **fetal viability**, and estimate gestational age. - **Fetal anatomical structures** are not yet sufficiently developed for detailed assessment or Doppler studies of most circulatory components.

Q: A pregnant patient with a prosthetic valve on warfarin should be switched to heparin at

36 weeks. ***36 weeks*** - At **36 weeks of gestation**, a pregnant patient on **warfarin** (due to a prosthetic valve) should be switched to **unfractionated heparin (UFH)** or **low molecular weight heparin (LMWH)**. - This timing is crucial to mitigate the risk of fetal coagulopathy from warfarin exposure during delivery and to allow for safer management of anticoagulation during labor and delivery. *30 weeks* - Switching to heparin at 30 weeks is generally too early and unnecessarily prolongs the period of subcutaneous injections, which can be burdensome for patients. - The primary concern of fetal coagulopathy with warfarin is highest closer to term, making a switch at 36 weeks more appropriate for balancing maternal and fetal risks. *38 weeks* - Switching at 38 weeks significantly increases the risk that labor might occur while the patient is still on warfarin, exposing the fetus to the drug and increasing the risk of maternal bleeding complications during delivery. - It leaves little buffer time for the warfarin's effects to wear off before spontaneous labor might begin. *Onset of labour* - Waiting until the onset of labor to switch from warfarin to heparin is dangerous and inappropriate. - Warfarin has a long half-life, and its anticoagulant effects would still be present during labor and delivery, posing a high risk of fetal hemorrhage (especially intracranial hemorrhage) and significant maternal bleeding.

Q: Following tests are done for assessing fetal lung maturity. Which of the following test results does not indicate adequate fetal lung maturity?

Lecithin/sphingomyelin ratio less than 2. ***Lecithin/sphingomyelin ratio less than 2*** - A **lecithin/sphingomyelin (L/S) ratio** of **less than 2:1** indicates a higher risk of respiratory distress syndrome (RDS) due to insufficient **surfactant** production. - Surfactant is crucial for reducing surface tension in the alveoli, preventing their collapse at the end of expiration. - An L/S ratio **≥2:1** is considered indicative of fetal lung maturity. *Foam stability index greater than 47* - A **foam stability index (FSI) greater than or equal to 47** indicates the presence of sufficient **surfactant** to create stable foam, suggesting **fetal lung maturity**. - This test is based on the ability of surfactant to reduce surface tension in amniotic fluid when mixed with ethanol. *Presence of phosphatidylglycerol* - The **presence of phosphatidylglycerol (PG)** in the amniotic fluid is a strong indicator of **fetal lung maturity**. - PG is a mature **surfactant** component that appears later in gestation and signifies a very low risk of respiratory distress syndrome (RDS). *Optical density at 650 nm less than 0.15* - An **optical density (OD) at 650 nm of less than 0.15** in the amniotic fluid indicates **fetal lung maturity**. - This test measures the turbidity of amniotic fluid, with lower values indicating the presence of mature surfactant and clear fluid.

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: In a macerated baby, the ideal sample for genetic analysis is obtained from:

Placental Tissue. ***Placental Tissue*** - **Placental tissue** (chorionic villi) is preferred for genetic analysis in macerated fetuses because it is less susceptible to **autolysis** and **bacterial contamination** compared to fetal tissues. - The placenta often retains viable cells with intact DNA even when fetal tissues have significantly degraded, making it a more reliable source for **karyotyping** or **molecular genetic studies**. *Clotted fetal blood* - **Clotted fetal blood** from a macerated fetus is generally unsuitable due to significant **cellular degradation** and **DNA fragmentation** caused by autolysis. - The quality of DNA extracted from such a sample would likely be poor, leading to unreliable or unsuccessful genetic testing. *Fibroblast from skin* - While fibroblasts can be cultured from skin, obtaining a viable biopsy from a **macerated fetus** is challenging due to extensive **tissue degradation** and the high risk of **bacterial contamination**. - Successful culture and growth of fibroblasts would be unlikely given the compromised state of the fetal tissue. *Fibroblast from Achilles tendon* - Similar to skin, obtaining viable fibroblasts from the **Achilles tendon** of a macerated fetus is difficult due to widespread **autolysis** and **tissue degeneration**. - The degradation of cells in macerated fetuses significantly reduces the chances of culturing viable cells needed for genetic analysis from any fetal tissue, including tendons.

Question 1

What is the critical value of the shock index that is considered abnormal in pregnancy?

Accepted Answer

0.9-1.1

Answer

0.3-0.5

Answer

0.7-0.9

Answer

0.5-0.7

Question 2

At what gestational age is transabdominal color Doppler sonography optimally performed to assess fetal well-being?

Accepted Answer

18-20 weeks

Answer

Done before 10 weeks

Answer

11-13 weeks

Answer

5-7 weeks

Question 3

A pregnant patient with a prosthetic valve on warfarin should be switched to heparin at

Accepted Answer

36 weeks

Answer

Onset of labour

Answer

30 weeks

Answer

38 weeks

Question 4

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 5

Following tests are done for assessing fetal lung maturity. Which of the following test results does not indicate adequate fetal lung maturity?

Accepted Answer

Lecithin/sphingomyelin ratio less than 2

Answer

Foam stability index greater than 47

Answer

Presence of phosphatidylglycerol

Answer

Optical density at 650 nm less than 0.15

Question 6

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 7

The weight of the placenta at term is

Accepted Answer

500 gm

Answer

250 gm

Answer

1000 gm

Answer

750 gm

Question 8

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 9

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 10

In a macerated baby, the ideal sample for genetic analysis is obtained from:

Accepted Answer

Placental Tissue

Answer

Clotted fetal blood

Answer

Fibroblast from skin

Answer

Fibroblast from Achilles tendon

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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