Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine Indian Medical PG Practice Questions and MCQs

Question 1311: In twin pregnancies, what is the minimum percentage difference in size that indicates significant discordance?

A. 15% with the smaller twin as index
B. 25% with the larger twin as index (Correct Answer)
C. 25% with the smaller twin as index
D. 15% with the larger twin as index

Explanation: ***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.

Question 1312: Which sign is seen in ultrasound for monochorionic diamniotic twins?

A. T sign (Correct Answer)
B. Lambda sign
C. Twin peak sign
D. Membrane thickness >2mm

Explanation: ***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.

Question 1313: What is the earliest and most conclusive sign of intrauterine fetal death?

A. Spalding sign (Correct Answer)
B. Crowding of ribs
C. Hyperflexion of spine
D. Intrafetal gas in areas of the great vessels and heart

Explanation: ***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.

Question 1314: Which of the following statements about HIV transmission in pregnancy is true?

A. Perinatal transmission of HIV is common.
B. With effective ART, the chance of transmission can be reduced to less than 1%. (Correct Answer)
C. Pregnancy increases the risk of acquiring HIV.
D. LSCS significantly increases the chances of HIV transmission.

Explanation: **With effective ART, the chance of transmission can be reduced to less than 1%.** - **Antiretroviral therapy (ART)** during pregnancy, labor, and for the newborn is highly effective in reducing **vertical transmission** of HIV. - When a pregnant woman with HIV adheres to an effective ART regimen and achieves viral suppression, the risk of transmission to her baby can be as low as **0.1-0.5%** (well below 1%). - This represents one of the greatest successes of modern obstetric medicine. *Perinatal transmission of HIV is common.* - Before the advent of effective ART, **perinatal transmission** rates were indeed high, around 15-45%. - However, with modern interventions including ART, elective cesarean section (when indicated), and avoidance of breastfeeding in resource-rich settings, transmission is now rare. *Pregnancy increases the risk of acquiring HIV.* - Pregnancy itself does not inherently increase a woman's **susceptibility to HIV infection**. - A woman's risk of acquiring HIV during pregnancy is primarily linked to **risky behaviors** and exposure to an infected partner, similar to non-pregnant individuals. *LSCS significantly increases the chances of HIV transmission.* - **Elective Lower Segment Cesarean Section (LSCS)** is recommended for pregnant women with **high viral loads** (>1,000 copies/mL) near term to *reduce* the risk of HIV transmission. - It is performed to avoid exposure of the fetus to maternal blood and genital secretions during vaginal birth, thereby *decreasing*, not increasing, transmission risk. - For women with viral loads <1,000 copies/mL on ART, vaginal delivery is safe and does not increase transmission risk.

Question 1315: Open neural tube defects are best diagnosed by:

A. Detailed fetal ultrasound examination (Correct Answer)
B. Radiographic imaging techniques
C. Screening with maternal serum alpha-fetoprotein
D. Measurement of acetylcholinesterase in amniotic fluid

Explanation: ***Detailed fetal ultrasound examination*** - **High-resolution ultrasound** is the **primary and best diagnostic method** for open neural tube defects in current obstetric practice. - It can detect **anencephaly** with nearly **100% sensitivity** and **spina bifida** with **90-95% sensitivity** when performed by experienced sonographers. - Ultrasound can identify characteristic signs such as the **lemon sign** (scalloping of frontal bones), **banana sign** (cerebellar abnormality), and direct visualization of **spinal defects**. - It is **non-invasive**, widely available, and performed routinely during the **18-20 week anomaly scan**, making it the most practical and effective diagnostic tool. *Measurement of acetylcholinesterase in amniotic fluid* - While **acetylcholinesterase (AChE)** in amniotic fluid is highly specific for open neural tube defects, it requires **invasive amniocentesis** with associated risks (miscarriage, infection). - This test is now **rarely used** in modern practice due to the high accuracy of ultrasound. - It may serve as a **confirmatory test** in equivocal cases or when ultrasound findings are inconclusive, but it is not the first-line or "best" diagnostic method. *Screening with maternal serum alpha-fetoprotein* - **Maternal serum alpha-fetoprotein (MSAFP)** is a **screening test**, not a diagnostic test. - Elevated MSAFP levels indicate **increased risk** for open neural tube defects but can also be elevated in multiple gestations, abdominal wall defects, fetal demise, and incorrect gestational age. - Positive screening requires **follow-up with detailed ultrasound** for definitive diagnosis. *Radiographic imaging techniques* - **Radiographic imaging** (X-rays) is not used for prenatal diagnosis of neural tube defects due to **radiation exposure risks** and poor soft tissue visualization. - Ultrasound and MRI are preferred imaging modalities; X-rays have no role in prenatal diagnosis of open neural tube defects.

Question 1316: What is the first-line drug of choice for managing seizures in eclampsia?

A. Magnesium Sulphate (Correct Answer)
B. Nifedipine
C. Hydralazine
D. Labetalol

Explanation: ***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**.

Question 1317: Treatment of choice for a 28-week pregnant female with pain due to a 10 cm x 10 cm fibroid in the fundus is:

A. Uterine artery embolization
B. Laparoscopic myomectomy
C. Abdominal hysterectomy
D. Observation and symptomatic treatment (Correct Answer)

Explanation: ***Observation and symptomatic treatment*** - For a symptomatic fibroid in a **28-week pregnant woman**, conservative management with **analgesics** and rest is the primary approach to avoid harming the fetus. - Complications from fibroids during pregnancy, such as pain, often resolve with conservative care, and surgical intervention is generally reserved for severe, refractory cases. *Uterine artery embolization* - This procedure is **contraindicated in pregnancy** due to the risk of fetal compromise, including ischemia, miscarriage, or preterm labor. - It is typically used for non-pregnant women with symptomatic fibroids who wish to preserve fertility. *Laparoscopic myomectomy* - **Myomectomy during pregnancy** carries a high risk of significant bleeding, uterine contractions, and potential preterm labor or miscarriage. - While open myomectomy may be considered in rare, dire situations (e.g., torsion of a pedunculated fibroid), laparoscopic surgery is generally avoided due to technical difficulties and risks in a gravid uterus. *Abdominal hysterectomy* - **Hysterectomy** involves removal of the uterus and is a definitive treatment for fibroids, but it is **absolutely contraindicated in a pregnant woman** who desires to carry the pregnancy to term. - This procedure would result in the loss of the fetus and the ability to bear children.

Question 1318: Maximal hepatitis C virus transmission to the fetus in pregnancy depends on

A. Timing of maternal infection
B. Method of delivery
C. High level of HCV RNA (Correct Answer)
D. Duration of hepatitis C infection

Explanation: ***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 1319: Least common type of twins is:

A. Diamniotic-dichorionic twins
B. Diamniotic-monochorionic twins
C. Monoamniotic-monochorionic twins
D. Conjoined twins (Correct Answer)

Explanation: ***Conjoined twins*** - Conjoined twins are the **rarest form of twinning**, resulting from an incomplete separation of a monozygotic twin embryo. - They carry the **highest risks** and complications, including stillbirth and complex surgical separation challenges. *Diamniotic-dichorionic twins* - These are the **most common type of twins**, representing about 70-80% of all twin pregnancies, whether fraternal or identical. - Each twin has its **own amniotic sac and placenta**, leading to a relatively lower risk profile compared to monochorionic twins. *Diamniotic-monochorionic twins* - This type accounts for approximately 20-30% of all twin pregnancies and always involves **identical twins** sharing one placenta but having separate amniotic sacs. - They are at higher risk for complications like **twin-to-twin transfusion syndrome (TTTS)** due to shared placental circulation. *Monoamniotic-monochorionic twins* - This is a **rare form of identical twinning**, occurring in about 1% of monozygotic pregnancies, where twins share both the same placenta and the same amniotic sac. - The shared amniotic sac significantly increases the risk of **umbilical cord entanglement**, which can be life-threatening for both fetuses.

Question 1320: Placenta with an umbilical cord attached to its margin is called:

A. Battledore placenta (Correct Answer)
B. Circumvallate placenta
C. Succenturiate placenta
D. Velamentous placenta

Explanation: ***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).

Practice by Chapter

Fetal Assessment Techniques

Practice Questions

Hypertensive Disorders in Pregnancy

Practice Questions

Intrauterine Growth Restriction

Practice Questions

Multiple Gestation

Practice Questions

Rh Isoimmunization and Other Blood Group Incompatibilities

Practice Questions

Intrauterine Fetal Therapy

Practice Questions

Prenatal Diagnosis and Genetic Counseling

Practice Questions

Placental Abnormalities

Practice Questions

Preterm Labor and Delivery

Practice Questions

Management of Medical Disorders in Pregnancy

Practice Questions

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