Maternal-Fetal Medicine — MCQs

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.

Maternal-Fetal Medicine Indian Medical PG Practice Questions and MCQs

Question 1: What is the most common causative organism of acute pyelonephritis in pregnancy?

A. E. coli (Correct Answer)
B. Klebsiella pneumoniae
C. Enterobacter
D. Staphylococcus group

Explanation: **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.

Question 2: Which is the most common complication in monoamniotic twins?

A. Discordance
B. Cord entanglement
C. Conjoined twins
D. Intertwining (Correct Answer)

Explanation: **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.

Question 3: Placental enlargement is seen in which of the following infections?

A. Toxoplasma
B. Cytomegalovirus (CMV)
C. Parvovirus
D. Plasmodium (Correct Answer)

Explanation: **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.

Question 4: Hemolytic disease of the newborn is least common with which blood group female?

A. A
B. B
C. O (Correct Answer)
D. AB

Explanation: **Explanation:** The correct answer is **O**. This question refers to the risk of **Rh isoimmunization** (Rh incompatibility), which is the most severe form of hemolytic disease of the newborn (HDN). **Why Option C is correct:** In Rh isoimmunization, a Rh-negative mother carries a Rh-positive fetus. If the mother and fetus are also **ABO incompatible** (e.g., Mother is Type O and Fetus is Type A or B), the risk of Rh sensitization is significantly **reduced**. This is because any fetal red blood cells (RBCs) entering the maternal circulation are rapidly destroyed by the mother’s naturally occurring anti-A or anti-B antibodies before her immune system can recognize the Rh (D) antigen and produce anti-D antibodies. Since Type O individuals possess both anti-A and anti-B antibodies, they have the highest likelihood of ABO incompatibility with a non-O fetus, thereby providing a "protective effect" against Rh isoimmunization. **Why other options are incorrect:** * **Options A and B:** Mothers with blood group A or B only possess one type of isoagglutinin (anti-B or anti-A, respectively). They are less likely to have ABO incompatibility with the fetus compared to Type O mothers, leading to a higher risk of Rh sensitization. * **Option D (AB):** A mother with blood group AB has no anti-A or anti-B antibodies. Therefore, there is no ABO-mediated destruction of fetal cells, making her the most susceptible to Rh isoimmunization if she is Rh-negative. **High-Yield Clinical Pearls for NEET-PG:** 1. **ABO Incompatibility vs. Rh Incompatibility:** While ABO incompatibility is more common and can occur in the *first* pregnancy, it is clinically milder. Rh incompatibility is more severe and typically affects *subsequent* pregnancies. 2. **Protective Effect:** ABO incompatibility reduces the risk of Rh isoimmunization from ~16% to about **1-2%**. 3. **Kleihauer-Betke Test:** Used to quantify the amount of fetal-maternal hemorrhage to determine the dose of Anti-D (RhoGAM). 4. **Indirect Coombs Test (ICT):** Performed on the mother to detect sensitization. A titer of **1:16** is generally considered the critical threshold.

Question 5: Which of the following is associated with an increased incidence of heterotopic pregnancy?

A. Obesity
B. Multiparity
C. Prior cesarean delivery
D. Assisted reproductive technologies (Correct Answer)

Explanation: **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.

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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