Prenatal Care Practice Questions

Q: What is the earliest ultrasound sign of pregnancy in a transabdominal ultrasound scan?

Fundal endometrial thickening. **Explanation:** The earliest sonographic sign of pregnancy, particularly on a transabdominal scan (TAS), is **fundal endometrial thickening**. This occurs due to the decidual reaction—the hypertrophy and increased vascularity of the endometrial lining in preparation for implantation. This "decidual sign" appears as a thickened, echogenic endometrium before a distinct gestational sac can be visualized. **Analysis of Options:** * **A. Visible gestational sac:** While the gestational sac is the first *definitive* sign of an intrauterine pregnancy, it typically appears around 5 weeks of gestation on TAS (4.5 weeks on TVS). Endometrial thickening precedes this. * **B. Apparent embryonic structures:** The fetal pole (embryo) only becomes visible within the gestational sac at approximately 6 weeks of gestation. * **C. Fundal endometrial thickening (Correct):** This is the earliest non-specific sign, appearing in the late luteal phase/early pregnancy (approx. 3-4 weeks). * **D. Identifiable cardiac movements:** This is the first sign of a *viable* pregnancy, usually detected when the embryo reaches a crown-rump length (CRL) of 5mm (around 6-6.5 weeks). **High-Yield Clinical Pearls for NEET-PG:** * **Double Decidual Sign:** Two concentric echogenic rings surrounding the gestational sac; it helps differentiate a true gestational sac from a "pseudogestational sac" seen in ectopic pregnancy. * **Discriminatory Zone:** The serum β-hCG level at which a gestational sac should be visible (1500–2000 mIU/ml for TVS; 6500 mIU/ml for TAS). * **Mean Sac Diameter (MSD):** A gestational sac should be visible via TVS when the MSD is 2–3 mm.

Q: The triple test for the diagnosis of Down syndrome includes all of the following except?

Inhibin A. The **Triple Test** is a maternal serum screening performed between **15 and 20 weeks** of gestation (ideally 16–18 weeks) to screen for chromosomal abnormalities like Down syndrome (Trisomy 21) and neural tube defects. ### Why Inhibin A is the Correct Answer Inhibin A is **not** a component of the Triple Test. It is the fourth marker added to the Triple Test to create the **Quadruple (Quad) Test**. The addition of Inhibin A increases the sensitivity for detecting Down syndrome from approximately 65-70% (Triple Test) to 80-85% (Quad Test). ### Explanation of Incorrect Options (Components of Triple Test) In Down syndrome, the typical "Triple Test" profile shows: * **A. Beta-hCG:** Levels are characteristically **increased**. * **B. Alpha-fetoprotein (AFP):** Levels are characteristically **decreased**. (Note: AFP is increased in open neural tube defects). * **D. Serum Unconjugated Estriol (uE3):** Levels are characteristically **decreased**. ### High-Yield Clinical Pearls for NEET-PG * **Quadruple Test:** Includes AFP, uE3, hCG, and **Inhibin A** (Inhibin A is **increased** in Down syndrome). * **Mnemonic for Down Syndrome (Quad Test):** "HI" is High – **H**CG and **I**nhibin A are elevated; the others (AFP, uE3) are low. * **Edwards Syndrome (Trisomy 18):** All markers (AFP, uE3, and hCG) are typically **decreased**. * **Combined Test (First Trimester):** Performed at 11–13 weeks; includes PAPP-A (decreased), Beta-hCG (increased), and Nuchal Translucency (increased) on ultrasound. * **Best Screening Tool:** Cell-free DNA (cfDNA) / NIPT has the highest sensitivity (>99%) but is more expensive.

Q: At what gestational age can the earliest fetal heart activity be detected?

6.0-6.5 weeks. **Explanation:** The detection of fetal heart activity is a critical milestone in early pregnancy, serving as the definitive sign of a viable intrauterine pregnancy. **Why Option A is Correct:** The fetal heart is the first functional organ to develop. Spontaneous rhythmic contractions begin around the 22nd day of development (approximately 5 weeks of gestation). However, these are not consistently visible on imaging immediately. Using **Transvaginal Sonography (TVS)**, fetal heart activity can typically be detected when the Crown-Rump Length (CRL) reaches 1–2 mm, which corresponds to a gestational age of **6.0 to 6.5 weeks**. At this stage, the heart rate is relatively slow (approx. 100-110 bpm) before increasing. **Analysis of Incorrect Options:** * **Options B & C (6.5–7.5 weeks):** While heart activity is clearly visible during this window, it is not the *earliest* point of detection. By 7 weeks, the heart rate typically peaks around 175 bpm. * **Option D (8 weeks):** This is the timeframe when fetal heart activity can usually be detected via **Transabdominal Sonography (TAS)**. TAS has lower resolution than TVS and requires a larger embryo and more advanced gestation for accurate detection. **NEET-PG High-Yield Pearls:** * **TVS vs. TAS:** TVS can detect pregnancy milestones about 1 week earlier than TAS. * **Discriminatory Zone:** Fetal heart activity should always be visible by TVS when the CRL is **>7 mm**. If absent at this size, it suggests pregnancy failure (Missed Abortion). * **Mean Sac Diameter (MSD):** A yolk sac should be visible when the MSD is 20 mm (TVS); an embryo with a heartbeat should be visible when the MSD is **>25 mm**. * **Doppler:** While M-mode is used to document the rate, pulse-wave Doppler is generally avoided in the first trimester to prevent thermal bioeffects on the developing embryo.

Q: An obstetrician sees a pregnant patient who was exposed to rubella virus in the eighteenth week of pregnancy. She does not remember getting a rubella vaccination. What is the best immediate course of action?

Order a rubella antibody titer to determine immune status. The management of rubella exposure in pregnancy depends on the mother’s immune status and the gestational age at exposure. **Explanation of the Correct Answer:** The immediate priority is to determine if the mother is already immune. Many adults have immunity through childhood vaccination or prior subclinical infection. A **Rubella IgG antibody titer** should be ordered: * **If IgG is positive:** The patient is immune, and there is no risk of Congenital Rubella Syndrome (CRS). * **If IgG is negative:** The patient is susceptible. A second sample should be taken 2–3 weeks later to check for seroconversion (IgM/IgG), which would indicate an acute infection. **Analysis of Incorrect Options:** * **Option A:** Termination is not indicated without confirming maternal infection and assessing fetal risk. Furthermore, the risk of CRS decreases significantly after the first trimester. * **Option C:** This is factually incorrect. Rubella is most dangerous in the **first trimester** (up to 80% risk of CRS). While the risk drops after 16–18 weeks, exposure in the eighteenth week still requires investigation. * **Option D:** Rubella immune globulin does not reliably prevent fetal infection and is only considered if a susceptible woman refuses termination after a confirmed exposure. **NEET-PG High-Yield Pearls:** * **Maximum Risk:** The highest risk for CRS is during the first 12 weeks of gestation. * **Classic Triad of CRS:** Sensorineural deafness (most common), Cataracts (salt-and-pepper retinopathy), and Cardiac defects (Patent Ductus Arteriosus). * **Vaccination:** The Rubella vaccine (RA 27/3 strain) is a **live-attenuated vaccine** and is **contraindicated during pregnancy**. Women should avoid pregnancy for 1 month (28 days) after receiving the MMR vaccine. * **Postpartum:** If a pregnant woman is found to be non-immune, she should be vaccinated in the immediate postpartum period.

Q: At which gestational age is external cephalic version typically performed?

36 weeks. **Explanation:** External Cephalic Version (ECV) is a procedure where the fetus is manually rotated from a breech or transverse lie to a cephalic presentation through the maternal abdomen. **Why 36 weeks is correct:** The timing of ECV is a balance between the likelihood of spontaneous version and the risks of prematurity. * **In Nulliparous women:** ECV is typically performed at **36 weeks**. * **In Multiparous women:** It is often delayed until **37 weeks**. At 36 weeks, the fetus is large enough that spontaneous version is unlikely, yet there is still sufficient amniotic fluid and space to facilitate the maneuver. Most importantly, if a complication occurs (e.g., placental abruption or cord prolapse) necessitating emergency delivery, the fetus has reached near-term maturity. **Why other options are incorrect:** * **34 weeks:** Too early. Many fetuses (approx. 25%) will undergo spontaneous version to cephalic before 36 weeks. Performing it now increases the risk of the fetus reverting to breech and exposes a preterm infant to unnecessary delivery risks if complications arise. * **38/40 weeks:** Too late. As the pregnancy advances, the fetus grows larger and the relative volume of amniotic fluid decreases, significantly reducing the success rate of the procedure. **High-Yield Clinical Pearls for NEET-PG:** * **Prerequisites:** Reactive NST (reassuring fetal heart rate), adequate liquor, and no contraindications to vaginal delivery. * **Success Rate:** Approximately 50–60%. * **Tocolysis:** Use of beta-mimetics (e.g., Terbutaline) increases success rates by relaxing the uterus. * **Absolute Contraindications:** Placenta previa, multifetal gestation, ruptured membranes, and prior classical cesarean section. * **Rh Status:** Rh-negative non-sensitized mothers must receive **Anti-D immunoglobulin** after the procedure to prevent isoimmunization.

Q: In Down syndrome, which of the following markers is NOT typically measured in the second-trimester quadruple screening test performed between 14-20 weeks of gestation?

Progesterone. The **Quadruple Screening Test** (Quad Screen) is a prenatal screening tool performed between **15 and 20 weeks** (ideally 16–18 weeks) of gestation to assess the risk of chromosomal abnormalities like Down syndrome (Trisomy 21) and Trisomy 18, as well as neural tube defects. ### Why Progesterone is the Correct Answer: **Progesterone** is not a component of the Quad screen. While it is essential for maintaining pregnancy, its levels do not serve as a reliable predictive marker for fetal aneuploidy. The fourth marker added to the "Triple Screen" to create the "Quad Screen" is **Inhibin A**, which significantly increases the sensitivity for detecting Down syndrome. ### Explanation of Incorrect Options (The Quad Markers): In a pregnancy affected by **Down syndrome**, the markers typically show the following patterns: * **Alpha-fetoprotein (AFP):** Levels are **decreased**. (Low AFP is also seen in Trisomy 18). * **Human chorionic gonadotropin (hCG):** Levels are **increased**. * **Inhibin A:** Levels are **increased**. * **Unconjugated Estriol (uE3):** (Not listed in options but the 4th marker) Levels are **decreased**. ### High-Yield Clinical Pearls for NEET-PG: * **Mnemonic for Down Syndrome (HI):** **H**CG and **I**nhibin A are **HI**gh; the others (AFP and uE3) are low. * **Trisomy 18 (Edwards Syndrome):** All markers (AFP, hCG, uE3) are typically **decreased**. * **Neural Tube Defects (NTD):** Characterized by **elevated AFP** levels. * **First Trimester Screening (11–13.6 weeks):** Uses PAPP-A (decreased), β-hCG (increased), and Nuchal Translucency (increased) for Down syndrome. * **Confirmatory Test:** Screening tests are not diagnostic. If the Quad screen is positive, definitive diagnosis requires **Amniocentesis** or **CVS**.

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.

Question 1

Which of the following is unrelated to fetal souffle?

Accepted Answer

It is due to the rush of blood through the umbilical arteries.

Answer

It is a soft blowing murmur synchronous with the fetal heart sounds.

Answer

It is heard in approximately 15% of cases.

Answer

Its presence is diagnostic of pregnancy.

Question 2

What is the earliest ultrasound sign of pregnancy in a transabdominal ultrasound scan?

Accepted Answer

Fundal endometrial thickening

Answer

Visible gestational sac

Answer

Apparent embryonic structures

Answer

Identifiable cardiac movements

Question 3

The triple test for the diagnosis of Down syndrome includes all of the following except?

Accepted Answer

Inhibin A

Answer

Beta hCG

Answer

Alpha-fetoprotein

Answer

Serum estriol level

Question 4

At what gestational age can the earliest fetal heart activity be detected?

Accepted Answer

6.0-6.5 weeks

Answer

6.5-7 weeks

Answer

7.1-7.5 weeks

Answer

8 weeks

Question 5

An obstetrician sees a pregnant patient who was exposed to rubella virus in the eighteenth week of pregnancy. She does not remember getting a rubella vaccination. What is the best immediate course of action?

Accepted Answer

Order a rubella antibody titer to determine immune status

Answer

Terminate the pregnancy

Answer

Reassure the patient because rubella is not a problem until after the thirtieth week

Answer

Administer rubella immune globulin

Question 6

At which gestational age is external cephalic version typically performed?

Accepted Answer

36 weeks

Answer

34 weeks

Answer

38 weeks

Answer

40 weeks

Question 7

In Down syndrome, which of the following markers is NOT typically measured in the second-trimester quadruple screening test performed between 14-20 weeks of gestation?

Accepted Answer

Progesterone

Answer

Alpha-fetoprotein

Answer

Human chorionic gonadotropin (hCG)

Answer

Inhibin A

Question 8

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 9

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 10

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

Prenatal Care — MCQs

Prenatal Care — MCQs

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