Prenatal Care Practice Questions

Q: Alpha-fetoprotein in maternal serum and/or amniotic fluid is increased in all except:

Down's syndrome. **Explanation:** Alpha-fetoprotein (AFP) is a glycoprotein synthesized by the fetal yolk sac and later by the fetal liver. It is the fetal equivalent of albumin. Monitoring maternal serum AFP (MSAFP) is a crucial screening tool during the second trimester (15–20 weeks). **1. Why Down’s Syndrome is the Correct Answer:** In **Down’s Syndrome (Trisomy 21)**, maternal serum AFP levels are characteristically **decreased** (typically <0.5 MoM). While the exact pathophysiology is not fully understood, it is believed to result from decreased synthesis by the fetal liver or a smaller-than-normal yolk sac. In a "Triple Test" for Down’s Syndrome, you typically see: * **Decreased:** AFP and Unconjugated Estriol (uE3). * **Increased:** hCG and Inhibin-A. **2. Analysis of Incorrect Options (Conditions with Increased AFP):** AFP levels increase whenever there is a defect in the fetal epithelial barrier, allowing AFP to leak into the amniotic fluid and maternal circulation. * **Neural Tube Defects (NTDs):** Open NTDs like **Anencephaly (C)** and **Encephalocele (D)** involve a failure of the neural tube to close, leading to massive leakage of AFP. * **Fetal Neural Tube Defects (A):** This is the broad category encompassing Spina Bifida, Anencephaly, and Encephalocele. **3. NEET-PG High-Yield Pearls:** * **Most common cause of increased MSAFP:** Incorrect dating (underestimation of gestational age). * **Other causes of Increased AFP:** Omphalocele, Gastroschisis (ventral wall defects), Multiple gestations, and Renal anomalies (Finnish-type nephrosis). * **Other causes of Decreased AFP:** Trisomy 18 (Edwards Syndrome), Molar pregnancy, and Fetal macrosomia (maternal diabetes). * **Confirmatory Test:** If MSAFP is elevated, the next step is Ultrasound [1]; if still suspicious, Amniocentesis is performed to check for AFP and **Acetylcholinesterase (AChE)** levels (AChE is highly specific for open NTDs).

Q: Which of the following is NOT correct regarding respiratory function during the late trimester of normal pregnancy?

Lung compliance is decreased.. In normal pregnancy, significant physiological adaptations occur in the respiratory system to meet the increased oxygen demands of the fetus and the mother. **Explanation of the Correct Answer (C):** **Lung compliance does NOT change** during pregnancy. While the enlarging uterus causes the diaphragm to rise by approximately 4 cm, the chest wall diameter increases and the ribs flare out (mediated by the hormone relaxin). This maintains the overall compliance of the respiratory system. Therefore, the statement that lung compliance is decreased is incorrect. **Analysis of Incorrect Options:** * **Option A:** Progesterone acts as a direct respiratory stimulant. It increases the sensitivity of the respiratory center to $CO_2$, leading to an increase in **Tidal Volume (by ~40%)** and **Resting Minute Ventilation (by ~40-50%)**. * **Option B:** Due to the elevation of the diaphragm, the **Functional Residual Capacity (FRC)** and **Residual Volume (RV)** are decreased by approximately 20%. This is a high-yield fact often tested in exams. * **Option D:** Progesterone causes relaxation of the smooth muscles in the tracheobronchial tree, which leads to a **reduction in total pulmonary resistance**. **High-Yield NEET-PG Pearls:** 1. **Vital Capacity (VC)** and **Inspiratory Capacity (IC)** remain unchanged or may slightly increase. 2. **Respiratory Rate** remains largely **unchanged**; the increase in minute ventilation is primarily due to increased tidal volume. 3. Pregnancy is a state of **compensated respiratory alkalosis** (pH 7.40–7.45) due to hyperventilation, which facilitates $CO_2$ transfer from the fetus to the mother. 4. **Dyspnea of pregnancy** is common and physiological, often starting in the first or second trimester.

Q: Amniocentesis is done for all of the mentioned indications EXCEPT?

Oligohydramnios. **Explanation:** Amniocentesis is a procedure where amniotic fluid is aspirated from the gravid uterus for diagnostic or therapeutic purposes. The correct answer is **Oligohydramnios** because it is a **contraindication** (or a technical limitation) rather than an indication. 1. **Why Oligohydramnios is the Correct Answer:** Amniocentesis requires an adequate pocket of amniotic fluid to safely insert the needle without injuring the fetus or the umbilical cord. In oligohydramnios (decreased fluid volume), the risk of fetal injury and "dry tap" (failure to obtain fluid) is significantly high. In fact, amniocentesis is often used to *treat* polyhydramnios (therapeutic amnioreduction), not oligohydramnios. 2. **Analysis of Other Options:** * **Fetal Lung Maturity:** Historically, the L/S ratio (Lecithin/Sphingomyelin) and Phosphatidylglycerol levels were measured via amniocentesis to assess lung maturity before elective preterm delivery. * **Congenital Infections:** Amniotic fluid PCR is the gold standard for diagnosing intrauterine infections like TORCH (especially CMV and Toxoplasmosis). * **Genetic Defects:** This is the most common indication. Amniotic fluid contains desquamated fetal cells (amniocytes) used for karyotyping, FISH, and chromosomal microarray to detect Down syndrome and other aneuploidies. **NEET-PG High-Yield Pearls:** * **Timing:** Ideally performed between **15–20 weeks** of gestation. * **Early Amniocentesis:** Done between 12–14 weeks; however, it is associated with a higher risk of clubfoot (talipes equinovarus) and procedure loss. * **Risk of Fetal Loss:** Approximately 0.5% (1 in 200). * **Rh-Negative Mothers:** Always administer Anti-D immunoglobulin after the procedure to prevent isoimmunization.

Q: A high level of hCG is seen in all of the following conditions EXCEPT:

Neural tube defect. **Explanation:** Human Chorionic Gonadotropin (hCG) is a glycoprotein hormone produced by the syncytiotrophoblast. Understanding its variations is crucial for prenatal screening and oncology. **Why Neural Tube Defects (NTDs) is the correct answer:** In cases of **Neural Tube Defects** (like anencephaly or spina bifida), the primary biochemical marker that increases is **Alpha-Fetoprotein (AFP)**, due to leakage from the exposed fetal tissues. hCG levels typically remain **normal** in isolated NTDs. Therefore, it is the "except" in this list. **Analysis of Incorrect Options:** * **Down Syndrome (Trisomy 21):** In the second-trimester quadruple screen, Down syndrome is characterized by **elevated hCG** and Inhibin-A, while AFP and unconjugated Estriol (uE3) are decreased (Mnemonic: **HI**gh for **H**CG and **I**nhibin). * **Gestational Trophoblastic Disease (GTD):** Conditions like Hydatidiform mole involve massive proliferation of trophoblastic tissue, leading to **extremely high levels of hCG** (often >100,000 mIU/mL). * **Germ Cell Tumors:** Certain ovarian or testicular germ cell tumors, specifically **Choriocarcinomas** and some Dysgerminomas/Embryonal carcinomas, secrete hCG as a tumor marker. **High-Yield NEET-PG Pearls:** * **Low hCG levels** are associated with: Ectopic pregnancy (lower than expected for gestational age), threatened abortion, and Edwards syndrome (Trisomy 18). * **High hCG levels** are also seen in: Multiple pregnancies and Rh isoimmunization (due to placental hydrops). * **AFP** is the marker of choice for NTDs; it is **decreased** in Down syndrome.

Q: A patient is at 20 weeks of gestation. The patient's last menstrual period (LMP) was on January 9th. What is the estimated date of delivery?

October 16th. **Explanation:** The estimated date of delivery (EDD) is calculated using **Naegele’s Rule**, which is a standard clinical tool used in obstetrics. According to this rule, the EDD is determined by adding **9 months and 7 days** to the first day of the patient’s last menstrual period (LMP). **Calculation for this case:** * **LMP:** January 9th * **Add 7 days:** January 9 + 7 = January 16th * **Add 9 months:** January + 9 months = **October 16th** **Analysis of Options:** * **Option C (Correct):** Follows Naegele’s Rule correctly (Jan 9 + 9 months + 7 days). * **Option A:** This is simply the date of the LMP, not the delivery date. * **Option B:** This date is exactly 36 weeks from the LMP, which is premature. * **Option D:** This adds 9 months but forgets to add the 7 days required by the formula. **Clinical Pearls for NEET-PG:** 1. **Naegele’s Rule Assumptions:** It assumes a standard 28-day menstrual cycle with ovulation occurring on day 14. 2. **Cycle Adjustment:** If a patient has a longer cycle, add the extra days (e.g., for a 30-day cycle, add 9 days instead of 7). If shorter, subtract the difference. 3. **Alternative Formula:** You can also calculate EDD by subtracting 3 months from the LMP and adding 7 days and 1 year. 4. **Gold Standard:** While Naegele’s Rule is used for LMP, **First Trimester Ultrasound (Crown-Rump Length)** is the most accurate method for dating a pregnancy.

Q: All of the following are considered as high-risk pregnancy except?

Short-statured primi (150 cm and below). In prenatal care, a **high-risk pregnancy** is one where the mother, fetus, or newborn is at increased risk of adverse outcomes. ### Why Option B is the Correct Answer The standard clinical definition for a "short-statured primi" in the context of high-risk screening is a height of **140 cm (4'7") or below**, not 150 cm. While a woman measuring 150 cm is relatively short, she is not automatically categorized as "high-risk" unless other complications exist. A height of $\leq$ 140 cm is a significant risk factor because it is strongly associated with a **contracted pelvis**, increasing the risk of Cephalopelvic Disproportion (CPD) and obstructed labor. ### Analysis of Other Options * **A. Elderly Primi ($\geq$ 30 years):** Women embarking on their first pregnancy at age 30 or older are high-risk due to increased incidences of pre-eclampsia, gestational diabetes, chromosomal abnormalities (like Down Syndrome), and uterine fibroids. * **C. Previous Cesarean/Instrumental Delivery:** These patients are at risk for uterine rupture (in the case of prior C-section) or recurrent mechanical issues that necessitated instrumental intervention previously. * **D. Prolonged Pregnancy:** A pregnancy extending 14 days beyond the EDD (Post-term, $\geq$ 42 weeks) is high-risk due to **placental insufficiency**, oligohydramnios, and meconium aspiration syndrome. ### NEET-PG High-Yield Pearls * **Short Stature Cut-off:** Always remember the **140 cm** threshold for high-risk categorization in Indian guidelines. * **Age Extremes:** Both "Teenage Primi" ($<$ 18 years) and "Elderly Primi" ($\geq$ 30 years) are considered high-risk. * **The "Rule of Too":** Too young, too old, too many (grand multipara), and too soon (short birth interval) all define high-risk status.

Question 1

Alpha-fetoprotein in maternal serum and/or amniotic fluid is increased in all except:

Accepted Answer

Down's syndrome

Answer

Fetal neural tube defects

Answer

Anencephaly

Answer

Encephalocele

Question 2

Which of the following is NOT correct regarding respiratory function during the late trimester of normal pregnancy?

Accepted Answer

Lung compliance is decreased.

Answer

Tidal volume and resting minute ventilation increase.

Answer

Functional residual capacity and residual volume are decreased.

Answer

Total pulmonary resistance is reduced.

Question 3

As an isolated finding, which of the following is associated with the highest risk of Down syndrome?

Accepted Answer

Increased nuchal fold thickness

Answer

Shortened femur

Answer

Absence of nasal bone

Answer

Echogenic bowel

Question 4

Myelodysplasia in a fetus can be best diagnosed by which of the following methods?

Accepted Answer

Alpha-fetoprotein (AFP)

Answer

Lumbar puncture

Answer

Human chorionic gonadotropin (HCG)

Answer

Unconjugated estriol

Question 5

Amniocentesis is done for all of the mentioned indications EXCEPT?

Accepted Answer

Oligohydramnios

Answer

Fetal lung maturity

Answer

Congenital infections

Answer

Genetic defects

Question 6

What is the appropriate treatment for a woman experiencing edema during pregnancy?

Accepted Answer

Bed rest

Answer

Salt restriction

Answer

Fluid restriction

Answer

Diuretics

Question 7

A 32-year-old G3P20L2 presents to the obstetrician's office for a routine OB visit at 30 weeks gestation. She has had no complications during the pregnancy and has had regular prenatal care. Her gestational age is confirmed with a first-trimester sonogram. During the routine OB visit, the fundal height measures 35 cm. All of the following can explain the size-date discrepancy except?

Accepted Answer

The 5-cm difference is within the error for fundal height measurements

Answer

Leiomyomas

Answer

Polyhydramnios

Answer

Fetal macrosomia

Question 8

A high level of hCG is seen in all of the following conditions EXCEPT:

Accepted Answer

Neural tube defect

Answer

Down syndrome

Answer

Germ cell tumor

Answer

Gestational trophoblastic disease

Question 9

A patient is at 20 weeks of gestation. The patient's last menstrual period (LMP) was on January 9th. What is the estimated date of delivery?

Accepted Answer

October 16th

Answer

January 9th

Answer

September 16th

Answer

October 9th

Question 10

All of the following are considered as high-risk pregnancy except?

Accepted Answer

Short-statured primi (150 cm and below)

Answer

Elderly primi (30 years and over)

Answer

History of previous cesarean or instrumental delivery

Answer

Prolonged pregnancy (14 days after expected date of delivery)

Prenatal Care — MCQs

Prenatal Care — MCQs

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