Maternal-Fetal Medicine Practice Questions

Q: What is the most common causative organism of acute pyelonephritis in pregnancy?

E. coli. **Explanation:** **1. Why E. coli is correct:** *Escherichia coli* is the most common causative organism for acute pyelonephritis in pregnancy, accounting for approximately **70–80% of cases**. The primary mechanism is the ascending route of infection. During pregnancy, physiological changes such as progesterone-induced smooth muscle relaxation (leading to ureteral dilatation) and mechanical compression of the ureters by the gravid uterus cause **urinary stasis**. This environment, combined with pregnancy-induced glycosuria and aminoaciduria, facilitates the upward migration of fecal flora (E. coli) from the perineum to the upper urinary tract. **2. Why the other options are incorrect:** * **B & C (Klebsiella and Enterobacter):** While these are Gram-negative bacilli that can cause UTIs, they are significantly less common than E. coli, typically accounting for only 3–5% of cases each. They are more frequently seen in recurrent infections or hospital-acquired settings. * **D (Staphylococcus group):** Gram-positive organisms like *Staphylococcus saprophyticus* or Group B Streptococcus (GBS) are occasional causes of UTI in pregnancy, but they represent a small minority of pyelonephritis cases compared to the overwhelming prevalence of E. coli. **3. NEET-PG High-Yield Pearls:** * **Most common medical complication** requiring hospitalization during pregnancy: Acute Pyelonephritis. * **Most common site:** Right side (due to dextrorotation of the uterus and protection of the left ureter by the sigmoid colon). * **Screening:** All pregnant women should be screened for **Asymptomatic Bacteriuria (ASB)** at the first prenatal visit (12–16 weeks). If untreated, 25–40% of ASB cases progress to acute pyelonephritis. * **Complications:** Can lead to preterm labor, maternal sepsis, and ARDS.

Q: Which is the most common complication in monoamniotic twins?

Intertwining. **Explanation:** Monoamniotic-monochorionic (MoMo) twins occur when the zygote divides late, between **8 to 12 days** post-fertilization. Because both fetuses reside in a single amniotic sac without a dividing membrane, they are at unique risk for specific complications. **1. Why "Intertwining" is correct:** **Cord entanglement (Intertwining)** is the most common and characteristic complication of monoamniotic twins, occurring in nearly **100% of cases** in utero. As the fetuses move within the single sac, their umbilical cords inevitably twist around each other. While not always fatal, it can lead to sudden cord occlusion and fetal demise, which is why these pregnancies are managed with intensive monitoring and elective Cesarean delivery (usually at 32–34 weeks). **2. Analysis of Incorrect Options:** * **Discordance (A):** While growth discordance occurs in twins, it is more classically associated with Twin-to-Twin Transfusion Syndrome (TTTS) in diamniotic-monochorionic twins. * **Cord entanglement (B):** In many textbooks and exams, "Intertwining" and "Cord entanglement" are used interchangeably; however, "Intertwining" is the preferred clinical term for the specific phenomenon of the two cords wrapping around one another. * **Conjoined twins (C):** This is a rare complication occurring only if the zygote divides even later (**after 13 days**). While specific to monoamniotic gestations, it is far less common than cord intertwining. **High-Yield Clinical Pearls for NEET-PG:** * **Timing of Division:** 0–72 hours (Di-Di), 4–8 days (Mo-Di), 8–12 days (Mo-Mo), >13 days (Conjoined). * **Management:** MoMo twins require inpatient monitoring from 24–28 weeks and delivery via **LSCS by 32–34 weeks** to prevent late-term fetal death from cord accidents. * **The "T-sign" vs. "Lambda sign":** MoMo twins show **neither**; there is no dividing membrane at all.

Q: Placental enlargement is seen in which of the following infections?

Plasmodium. **Explanation:** **Correct Answer: D. Plasmodium** **Why Plasmodium is correct:** Placental enlargement (placentomegaly) in malaria, particularly *Plasmodium falciparum*, is a hallmark of **Placental Malaria**. The underlying mechanism involves the sequestration of parasitized red blood cells in the intervillous spaces. This triggers a robust maternal inflammatory response, leading to massive infiltration of monocytes and macrophages (intervillositis), fibrin deposition, and basement membrane thickening. These pathological changes significantly increase placental weight and thickness, often correlating with adverse outcomes like intrauterine growth restriction (IUGR) and low birth weight. **Analysis of Incorrect Options:** * **A, B, and C (Toxoplasma, CMV, Parvovirus):** While these infections are part of the TORCH spectrum and can occasionally cause placental edema or "hydrops-like" changes, they are primarily associated with **placental calcifications** (especially CMV and Toxoplasma) or specific fetal effects (e.g., Parvovirus causing fetal anemia and hydrops). In the context of standard PG-level examinations, *Plasmodium* is the classic infectious cause cited for significant placental hypertrophy and weight increase. **High-Yield Clinical Pearls for NEET-PG:** * **Definition of Placentomegaly:** A placental thickness >4 cm in the second/third trimester or a weight >600g at term. * **Other Causes of Placentomegaly:** * **Maternal:** Diabetes Mellitus (most common non-infectious cause), Severe Anemia. * **Fetal:** Rh-Isoimmunization (Hydrops Fetalis), Twin-to-Twin Transfusion Syndrome (recipient), Chromosomal anomalies (Triploidy). * **Tumors:** Chorioangioma. * **Malaria Fact:** Placental malaria is more common and severe in **primigravidae** due to the lack of specific immunity against VAR2CSA-expressing parasites that bind to chondroitin sulfate A in the placenta.

Q: Which of the following is associated with an increased incidence of heterotopic pregnancy?

Assisted reproductive technologies. **Explanation:** **Heterotopic pregnancy** is a rare clinical condition defined by the simultaneous presence of an intrauterine pregnancy and an ectopic pregnancy. **1. Why Assisted Reproductive Technologies (ART) is correct:** In the general population, the incidence of heterotopic pregnancy is approximately 1 in 30,000. However, with the rise of **Assisted Reproductive Technologies (ART)**, such as IVF and embryo transfer, the incidence increases significantly to about **1 in 100 to 1 in 500**. The primary mechanism is the transfer of multiple embryos into the uterus and the use of high-pressure catheters, which can inadvertently propel an embryo into the fallopian tube while another implants in the endometrium. **2. Why other options are incorrect:** * **Obesity:** While obesity is a risk factor for various pregnancy complications (like gestational diabetes), it is not a specific risk factor for heterotopic or ectopic pregnancy. * **Multiparity:** Higher parity does not increase the risk of heterotopic pregnancy. In fact, nulliparity is more often associated with ART use. * **Prior Cesarean Delivery:** This increases the risk of *placenta accreta* or *cesarean scar ectopic pregnancy*, but it is not the primary driver for a dual-site heterotopic pregnancy. **3. NEET-PG High-Yield Pearls:** * **Most common site:** The most common site for the ectopic component in a heterotopic pregnancy is the **Fallopian tube** (specifically the ampulla). * **Clinical Suspicion:** Always suspect heterotopic pregnancy in an ART patient who presents with an intrauterine pregnancy on ultrasound but has persistent abdominal pain or free fluid in the pouch of Douglas. * **Management:** The goal is to surgically remove the ectopic pregnancy (usually via laparoscopy) while preserving the viable intrauterine pregnancy. Methotrexate is **contraindicated** as it would terminate the intrauterine fetus.

Q: What is the impact on the fetus in case of use of Indomethacin in utero in the third trimester?

Early closure of ductus arteriosus. **Explanation:** **Mechanism of Action:** Indomethacin is a non-steroidal anti-inflammatory drug (NSAID) that acts as a non-selective **cyclooxygenase (COX) inhibitor**. In the fetus, the patency of the ductus arteriosus is actively maintained by high levels of circulating **Prostaglandin E2 (PGE2)**. By inhibiting COX enzymes, Indomethacin decreases prostaglandin synthesis, leading to the **premature (early) closure of the ductus arteriosus** in utero. This can result in fetal pulmonary hypertension and right-sided heart failure. **Analysis of Options:** * **Option B (Correct):** As explained, PGE2 inhibition leads to constriction and premature closure of the ductus. This risk increases significantly when used after **32 weeks** of gestation. * **Option A:** Patent Ductus Arteriosus (PDA) is the failure of the ductus to close *after* birth. Interestingly, Indomethacin is used postnatally to *treat* PDA, but its prenatal use causes the opposite (premature closure). * **Options C & D:** Ventricular and Atrial Septal Defects are structural congenital heart diseases related to embryological development in the first trimester. Indomethacin does not cause these malformations when used in the third trimester. **High-Yield Clinical Pearls for NEET-PG:** * **Tocolysis:** Indomethacin is used as a second-line tocolytic for preterm labor, but only before 32 weeks. * **Oligohydramnios:** Another major side effect of Indomethacin is reduced fetal urine output, leading to oligohydramnios (often used therapeutically in polyhydramnios). * **Monitoring:** If used for >48 hours, serial fetal echocardiography is mandatory to monitor the ductal flow and amniotic fluid index. * **Contraindication:** It is generally avoided after 32 weeks due to the high sensitivity of the fetal ductus to prostaglandins at this stage.

Q: Oligohydramnios is seen in which of the following conditions?

Renal agenesis. **Explanation:** **Correct Answer: A. Renal agenesis** The volume of amniotic fluid is a balance between production and removal. From the second trimester onwards, **fetal urine** is the primary source of amniotic fluid. In **Renal agenesis** (Potter sequence), the absence of kidneys leads to a lack of urine production (anuria), resulting in **Oligohydramnios** (Amniotic Fluid Index < 5 cm or Single Deepest Pocket < 2 cm). **Why the other options are incorrect:** * **B. Oesophageal atresia:** Fetal swallowing is the major pathway for amniotic fluid removal. In esophageal atresia, the fetus cannot swallow the fluid, leading to its accumulation and **Polyhydramnios**. * **C. Exomphalos (Omphalocele):** This is a ventral wall defect. It is generally associated with **Polyhydramnios** due to the exudation of fluid from the exposed bowel or associated chromosomal/structural anomalies that interfere with swallowing. * **D. Neural tube defect (NTD):** Open NTDs (like Anencephaly) cause **Polyhydramnios** via two mechanisms: the absence of the swallowing reflex and the transudation of cerebrospinal fluid across the exposed neural membranes. **High-Yield Clinical Pearls for NEET-PG:** * **Potter Sequence:** Renal agenesis → Oligohydramnios → Pulmonary hypoplasia, limb deformities, and flattened facies. * **Amniotic Fluid Index (AFI):** Normal range is 5–25 cm. * **Common causes of Oligohydramnios (DRIPPC):** **D**eath (fetal), **R**enal anomalies, **I**UGR, **P**rom (Premature Rupture of Membranes), **P**ost-term pregnancy, **C**hromosomal anomalies. * **Indomethacin:** A common drug-induced cause of oligohydramnios (due to reduced fetal renal blood flow).

Q: An ectopic pregnancy is shed as?

Decidua vera. In an ectopic pregnancy, the hormonal changes (rising progesterone) stimulate the transformation of the endometrium into **decidua**, despite the embryo being implanted outside the uterine cavity. ### Why Decidua Vera is Correct The endometrium undergoes a "decidual reaction" to prepare for implantation. In a normal intrauterine pregnancy, the decidua is divided into three layers: 1. **Decidua Basalis:** Where the blastocyst implants. 2. **Decidua Capsularis:** Covers the blastocyst. 3. **Decidua Vera (Parietalis):** Lines the remainder of the uterine cavity. In an **ectopic pregnancy**, there is no blastocyst inside the uterus to create the basalis or capsularis layers. Therefore, the entire uterine lining transforms uniformly into **Decidua Vera**. When the ectopic pregnancy fails and hormone levels fall, this lining sloughs off and is shed, often as a single intact piece known as a **decidual cast**. ### Why Other Options are Incorrect * **Decidua Basalis & Capsularis:** These layers only form in response to the physical presence and implantation of the embryo within the uterus. Since the embryo is extrauterine, these specific layers do not exist. * **Decidua Rubra:** This is not a standard anatomical term for the decidual layers; it is likely a distractor derived from "Lochia Rubra" (the bloody discharge seen postpartum). ### NEET-PG Clinical Pearls * **Arias-Stella Reaction:** This is the characteristic histological change seen in the endometrium during ectopic pregnancy, featuring hypersecretory glands and nuclear hypertrophy. * **Decidual Cast:** If a patient presents with abdominal pain and passes a fleshy mass per vaginum, it is often a decidual cast. This must be differentiated from a miscarriage (which would contain chorionic villi). * **Key Distinction:** The absence of chorionic villi on histopathology of the shed tissue is a strong indicator of ectopic pregnancy.

Question 1

What is the most common causative organism of acute pyelonephritis in pregnancy?

Accepted Answer

E. coli

Answer

Klebsiella pneumoniae

Answer

Enterobacter

Answer

Staphylococcus group

Question 2

Which is the most common complication in monoamniotic twins?

Accepted Answer

Intertwining

Answer

Discordance

Answer

Cord entanglement

Answer

Conjoined twins

Question 3

Placental enlargement is seen in which of the following infections?

Accepted Answer

Plasmodium

Answer

Toxoplasma

Answer

Cytomegalovirus (CMV)

Answer

Parvovirus

Question 4

Hemolytic disease of the newborn is least common with which blood group female?

Accepted Answer

O

Answer

A

Answer

B

Answer

AB

Question 5

Which of the following is associated with an increased incidence of heterotopic pregnancy?

Accepted Answer

Assisted reproductive technologies

Answer

Obesity

Answer

Multiparity

Answer

Prior cesarean delivery

Question 6

What is the impact on the fetus in case of use of Indomethacin in utero in the third trimester?

Accepted Answer

Early closure of ductus arteriosus

Answer

Patent ductus arteriosus

Answer

Ventricular septal defect

Answer

Atrial septal defect

Question 7

Which of the following are risk factors for preeclampsia?

Accepted Answer

Chronic hypertension, obesity, placental ischemia, antiphospholipid syndrome

Answer

Chronic hypertension, obesity, placental ischemia, multigravidae

Answer

Placental ischemia, multigravidae, antiphospholipid syndrome

Answer

Chronic hypertension, multigravidae, antiphospholipid syndrome

Question 8

Oligohydramnios is seen in which of the following conditions?

Accepted Answer

Renal agenesis

Answer

Oesophageal atresia

Answer

Exomphalos

Answer

Neural tube defect

Question 9

An ectopic pregnancy is shed as?

Accepted Answer

Decidua vera

Answer

Decidua basalis

Answer

Decidua capsularis

Answer

Decidua rubra

Question 10

A patient with systemic lupus erythematosus desires pregnancy. What should her physician advise her regarding pregnancy in lupus patients?

Accepted Answer

There may be an increase in spontaneous abortions and prematurity.

Answer

There is no increased risk to the fetus.

Answer

There may be an increase in cardiovascular malformations.

Answer

There may be an increase in nervous system malformations.

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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