Maternal-Fetal Medicine Practice Questions

Q: In twin pregnancies, what is the minimum percentage difference in size that indicates significant discordance?

25% with the larger twin as index. ***25% with the larger twin as index*** - **Discordant growth** in twin pregnancies is clinically defined as a **25% or greater difference in estimated fetal weight**, calculated using the larger twin as the reference. - This threshold helps predict adverse outcomes related to **unequal placental sharing** or other growth restrictions. *15% with the larger twin as index* - A 15% difference in estimated fetal weight is generally considered **within the normal range** and does not typically indicate significant discordance warranting intervention. - While it represents a difference, it may not be substantial enough to result in increased fetal morbidity or mortality. *15% with the smaller twin as index* - Using the smaller twin as the index for comparison at 15% would likely **overestimate the prevalence of discordance**, as smaller twins naturally contribute to a larger percentage difference when used as the denominator. - This method is not the standard clinical practice for defining significant twin growth discordance. *25% with the smaller twin as index* - Similar to using the smaller twin as the index at 15%, calculating a 25% difference based on the smaller twin would lead to a **misrepresentation of significant discordance**. - The standard definition specifies using the **larger twin's estimated weight** as the denominator for percentage calculation.

Q: Which sign is seen in ultrasound for monochorionic diamniotic twins?

T sign. ***T sign*** - The **T sign** is visualized on ultrasound when the inter-twin membrane inserts perpendicularly onto the chorionic plate, forming a "T" shape. - This specific finding indicates a **monochorionic twin gestation**, meaning they share a single chorion. *Lambda sign* - The **lambda (or twin peak) sign** is seen in dichorionic twin pregnancies, where the chorion extends into the base of the inter-twin membrane, forming a triangular projection. - This sign signifies the presence of **two separate chorions**, indicating a lower risk compared to monochorionic pregnancies. *Twin peak sign* - The **twin peak sign** is synonymous with the lambda sign and indicates a **dichorionic-diamniotic** twin pregnancy. - It results from the extension of placental tissue into the base of the inter-twin membrane, confirming two separate chorions. *Membrane thickness >2mm* - A **thick inter-twin membrane (>2mm)** is typically associated with **dichorionic-diamniotic** pregnancies due to the presence of two separate chorions and amnions. - In monochorionic-diamniotic pregnancies, the membrane is usually **thin** because it only consists of two amniotic layers.

Q: What is the earliest and most conclusive sign of intrauterine fetal death?

Spalding sign. ***Correct: Spalding sign*** - Spalding sign refers to the **overlapping of fetal skull bones** at the sutures, seen on radiological imaging (X-ray or ultrasound). - This occurs due to **liquefaction of the brain tissue** and loss of intracranial support after fetal death. - It is considered the **earliest conclusive radiological sign** of intrauterine fetal death, typically appearing **3-7 days** after fetal demise. - This sign is **highly specific** for fetal death and is widely recognized in obstetric practice. *Incorrect: Intrafetal gas in areas of the great vessels and heart* - Also known as **Robert's sign**, this represents gas formation within the fetal cardiovascular system due to decomposition. - While this is a **definitive sign** of fetal death, it is a **late finding** that typically appears **2-3 weeks after fetal demise**. - It requires significant bacterial decomposition and gas production, making it **not the earliest sign**. *Incorrect: Crowding of ribs* - This sign indicates **collapse of the fetal thoracic cage** due to maceration and loss of soft tissue support. - It is a **late manifestation** of fetal death and appears after more extensive decomposition. - This sign is **less specific** compared to Spalding sign. *Incorrect: Hyperflexion of spine* - **Hyperflexion of the fetal spine** results from loss of muscular tone and ligamentous support after death. - This is also a **late finding** associated with advanced maceration. - It is **not as early or specific** as Spalding sign for diagnosing intrauterine fetal death.

Q: Which of the following is a possible cause for the 'lambda' or 'twin peak' sign seen on ultrasound examination of a twin pregnancy?

Dichorionic Diamniotic Twins. ***Dichorionic Diamniotic Twins*** - This type of twinning occurs from two separate fertilization events, resulting in **two placentas** and **two amniotic sacs**. - On ultrasound, this would be represented by separate amniotic membranes and a thick, often triangular, inter-twin membrane (the **'lambda' or 'twin peak' sign**), indicating separate chorions. *Monochorionic Monoamniotic Twins* - These twins share **one placenta** and **one amniotic sac**, meaning there is no separating membrane between them. - This high-risk pregnancy is characterized by a lack of an inter-twin membrane on ultrasound. *Monochorionic Diamniotic Twins* - These twins share **one placenta** but have **two separate amniotic sacs**. - On ultrasound, a thin inter-twin membrane is visible, but this membrane does not contain chorionic tissue (it's often described as a **'T-sign'** where the membrane meets the chorion). *Conjoint Twins* - Conjoined twins are a rare form of monochorionic monoamniotic twins where the embryos **fail to completely separate**. - The ultrasound finding would show shared body parts, not simply specific membrane characteristics.

Q: Which of the following interventions has the STRONGEST evidence for reducing the risk of preeclampsia in high-risk pregnant women?

Low-dose aspirin (75-150 mg daily). ***Low-dose aspirin (75-150 mg daily)*** - **Low-dose aspirin** started before 16 weeks of gestation is the **only intervention with robust evidence** for reducing preeclampsia risk in high-risk women (ACOG, WHO, USPSTF recommendations). - Meta-analyses show **17-25% relative risk reduction** in preeclampsia when started early in pregnancy. - Recommended for women with history of preeclampsia, chronic hypertension, diabetes, kidney disease, or multifetal gestation. - Acts by **improving placental perfusion** and reducing thromboxane-mediated vasoconstriction. *Calcium supplementation (1.5-2g daily)* - **Calcium supplementation** shows benefit in **populations with low dietary calcium intake** (typically <600 mg/day). - Less effective in populations with adequate baseline calcium intake (most developed countries). - **WHO recommends** calcium for women in low-calcium settings but **not as first-line** in general high-risk populations. *Smoking cessation* - **Essential for healthy pregnancy** and reduces risks of placental abruption, preterm birth, and IUGR. - While smoking is associated with adverse outcomes, **cessation has not been proven to directly prevent preeclampsia**. - Some studies paradoxically show lower preeclampsia rates in smokers (confounded by lower PlGF levels), but smoking increases overall maternal-fetal morbidity. *Regular blood pressure monitoring* - **Critical for early detection** and management of hypertensive disorders but **does not prevent** their occurrence. - Allows timely intervention to **prevent progression to severe disease** and eclampsia. - Part of routine antenatal care but is a **surveillance measure, not a preventive intervention**.

Q: What is the first-line drug of choice for managing seizures in eclampsia?

Magnesium Sulphate. ***Magnesium Sulphate*** - **Magnesium sulphate** is the **first-line drug of choice** for both the prevention and treatment of seizures in **eclampsia** due to its superior efficacy. - It acts as a **central nervous system depressant** and a **vasodilator**, reducing cerebral edema and improving cerebral perfusion. *Nifedipine* - **Nifedipine** is a **calcium channel blocker** used primarily to manage **hypertension**, especially in **preeclampsia**. - While it can lower blood pressure, it is **not indicated** as a first-line agent for directly treating or preventing **eclamptic seizures**. *Hydralazine* - **Hydralazine** is a **direct-acting vasodilator** used to treat **severe hypertension** in pregnancy, including cases of preeclampsia. - Its primary role is blood pressure control, and it is **not effective** in preventing or treating **eclamptic seizures**. *Labetalol* - **Labetalol** is a **beta-blocker** and **alpha-blocker** used for the management of **hypertension** in pregnancy. - Like other antihypertensives, it addresses blood pressure but **does not have a primary role** in seizure management for **eclampsia**.

Q: Placenta with an umbilical cord attached to its margin is called:

Battledore placenta. ***Battledore placenta*** - This term describes a placenta where the **umbilical cord is inserted at the placental margin** (edge), resembling a badminton battledore. - While generally associated with a normal fetal outcome, it can increase the risk of **fetal growth restriction** and **preterm delivery**. *Circumvallate placenta* - Characterized by the fetal membranes (amnion and chorion) folding back on themselves at the edge of the placenta, forming a **thick, opaque ring**. - This condition is associated with an increased risk of **antepartum bleeding**, **placental abruption**, and **preterm labor**. *Succenturiate placenta* - Involves one or more **accessory placental lobes** that develop separately from the main placental disc, connected by blood vessels running through the membranes. - The primary concern is if an accessory lobe or connecting vessels are retained after birth, potentially leading to **postpartum hemorrhage** or **infection**. *Velamentous placenta* - Occurs when the **umbilical cord vessels branch out into the fetal membranes before reaching the placental disc**, making them unprotected by Wharton's jelly. - This configuration puts the vessels at high risk of **compression or rupture**, especially during labor, which can lead to **fetal hypoxia** or **exsanguination** (vasa previa).

Q: Maximal hepatitis C virus transmission to the fetus in pregnancy depends on

High level of HCV RNA. ***High level of HCV RNA*** - A **high maternal viral load (HCV RNA)** is the most significant risk factor for vertical transmission of hepatitis C virus (HCV) to the fetus. - This indicates greater viral replication and a higher chance of the virus crossing the placental barrier or being transmitted during delivery. *Timing of maternal infection* - While the timing of infection can impact overall disease progression, it is **not the primary determinant** of vertical transmission risk. - The **viral load at the time of delivery** is more critical than when the initial infection occurred. *Method of delivery* - Although there is a **slightly increased risk with vaginal delivery** compared to C-section, the **method of delivery is not the strongest predictor** of HCV transmission. - The benefits of a C-section for preventing HCV transmission are generally considered minimal. *Duration of hepatitis C infection* - The **chronicity or duration of infection** itself does not directly correlate with the risk of vertical transmission as strongly as the actual viral load at the time of delivery. - A long-standing infection with a low or undetectable viral load poses a lower risk than a recent infection with a high viral load.

Question 1

In twin pregnancies, what is the minimum percentage difference in size that indicates significant discordance?

Accepted Answer

25% with the larger twin as index

Answer

15% with the smaller twin as index

Answer

25% with the smaller twin as index

Answer

15% with the larger twin as index

Question 2

Which sign is seen in ultrasound for monochorionic diamniotic twins?

Accepted Answer

T sign

Answer

Lambda sign

Answer

Twin peak sign

Answer

Membrane thickness >2mm

Question 3

Which of the following statements about HIV transmission in pregnancy is true?

Accepted Answer

With effective ART, the chance of transmission can be reduced to less than 1%.

Answer

Perinatal transmission of HIV is common.

Answer

Pregnancy increases the risk of acquiring HIV.

Answer

LSCS significantly increases the chances of HIV transmission.

Question 4

What is the earliest and most conclusive sign of intrauterine fetal death?

Accepted Answer

Spalding sign

Answer

Crowding of ribs

Answer

Hyperflexion of spine

Answer

Intrafetal gas in areas of the great vessels and heart

Question 5

Which of the following is a possible cause for the 'lambda' or 'twin peak' sign seen on ultrasound examination of a twin pregnancy?

Accepted Answer

Dichorionic Diamniotic Twins

Answer

Monochorionic Monoamniotic Twins

Answer

Monochorionic Diamniotic Twins

Answer

Conjoint Twins

Question 6

Which of the following interventions has the STRONGEST evidence for reducing the risk of preeclampsia in high-risk pregnant women?

Accepted Answer

Low-dose aspirin (75-150 mg daily)

Answer

Smoking cessation

Answer

Calcium supplementation (1.5-2g daily)

Answer

Regular blood pressure monitoring

Question 7

Open neural tube defects are best diagnosed by:

Accepted Answer

Detailed fetal ultrasound examination

Answer

Radiographic imaging techniques

Answer

Screening with maternal serum alpha-fetoprotein

Answer

Measurement of acetylcholinesterase in amniotic fluid

Question 8

What is the first-line drug of choice for managing seizures in eclampsia?

Accepted Answer

Magnesium Sulphate

Answer

Nifedipine

Answer

Hydralazine

Answer

Labetalol

Question 9

Placenta with an umbilical cord attached to its margin is called:

Accepted Answer

Battledore placenta

Answer

Circumvallate placenta

Answer

Succenturiate placenta

Answer

Velamentous placenta

Question 10

Maximal hepatitis C virus transmission to the fetus in pregnancy depends on

Accepted Answer

High level of HCV RNA

Answer

Timing of maternal infection

Answer

Method of delivery

Answer

Duration of hepatitis C infection

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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