Prenatal Care Practice Questions

Q: The double decidual sac sign (DDSS) is the best ultrasound method for diagnosing which of the following?

Normal intrauterine pregnancy. **Explanation:** The **Double Decidual Sac Sign (DDSS)** is a classic early ultrasonographic marker used to confirm a **normal intrauterine pregnancy (IUP)** before a yolk sac or embryo is visible. It typically appears around 4.5 to 5 weeks of gestation. **Why it is the correct answer:** The DDSS consists of two concentric echogenic rings surrounding the gestational sac. These rings represent: 1. **Decidua capsularis:** The inner ring (surrounding the chorionic sac). 2. **Decidua parietalis:** The outer ring (lining the uterine cavity). The presence of these two distinct layers helps distinguish a true gestational sac from a "pseudogestational sac" (a collection of fluid or blood in the uterine cavity often seen in ectopic pregnancies). **Analysis of Incorrect Options:** * **Options A & B (Twins):** While ultrasound is used to diagnose chorionicity (e.g., the "Lambda" or "T" sign), the DDSS specifically identifies the presence of an IUP, not the number of amnions or chorions. "Monoamniotic Dichorionic" is also embryologically impossible (dichorionic twins are always diamniotic). * **Option C (Ectopic pregnancy):** The DDSS is used to *rule out* ectopic pregnancy by confirming that the pregnancy is located within the uterus. A pseudogestational sac in an ectopic pregnancy lacks the double-layered decidual appearance. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign of IUP:** The "Intrachorionic Sign" or the "Double Decidual Sac Sign." * **Mean Sac Diameter (MSD):** A yolk sac should be visible by transvaginal scan (TVS) when the MSD is **>8 mm**; a fetal pole should be visible when the MSD is **>16–25 mm**. * **Discriminatory Zone:** The level of β-hCG (usually 1,500–2,000 mIU/mL) at which a normal IUP must be visible on TVS. If the uterus is empty at this level, suspect ectopic pregnancy.

Q: What is true about hematological changes in pregnancy?

Total blood volume increases by 40% by term.. **Explanation:** The physiological adaptation to pregnancy involves significant expansion of the intravascular volume to support the metabolic demands of the fetus and protect the mother against blood loss during delivery. **1. Why Option A is Correct:** Total blood volume begins to increase as early as 6 weeks of gestation. It rises progressively, reaching a peak of approximately **40–50% above non-pregnant levels** by 32–34 weeks and remains elevated until term. This expansion is driven by an increase in both plasma volume and red cell mass. **2. Why the Other Options are Incorrect:** * **Options B & D:** While the Red Blood Cell (RBC) mass increases by about 20–30%, the **plasma volume increases disproportionately more** (about 45–50%). This results in hemodilution, leading to a **decrease** in hematocrit and hemoglobin concentration—a phenomenon known as **Physiological Anemia of Pregnancy**. * **Option C:** Red cell volume starts to increase at approximately **10 weeks** of gestation, not 20 weeks. The expansion is mediated by increased erythropoietin levels. **Clinical Pearls for NEET-PG:** * **Maximum Expansion:** Plasma volume expansion peaks at **32 weeks**. * **Hemoglobin Cut-off:** According to the WHO, anemia in pregnancy is defined as Hb **<11 g/dL**. * **Purpose:** The increased volume serves as a "buffer" for the blood loss during delivery (average 500 mL for vaginal birth; 1000 mL for C-section). * **Cardiac Output:** Increases by 30–50%, peaking early in the third trimester.

Q: What is a common cardiovascular change observed during pregnancy?

Slight left axis deviation in ECG. ### Explanation During pregnancy, the cardiovascular system undergoes significant anatomical and physiological adaptations to accommodate the growing fetus. **Why Option B is Correct:** As the uterus enlarges, it pushes the diaphragm upward. This elevation causes the heart to shift **upward and to the left**, rotating on its long axis. Consequently, the apex beat is displaced to the 4th intercostal space, lateral to the mid-clavicular line. On an ECG, this physical displacement manifests as a **slight left axis deviation (LAD)**. **Analysis of Incorrect Options:** * **A. Slight right axis deviation:** This is incorrect because the anatomical shift is superior and lateral (left), not rightward. * **C. Diastolic murmur:** While a **systolic flow murmur** (Grade I or II) is considered physiological in over 90% of pregnant women due to increased cardiac output and decreased blood viscosity, a **diastolic murmur is always pathological** and requires further investigation (e.g., echocardiography). * **D. Pulse rate is decreased:** This is incorrect. The resting heart rate typically **increases** by 10–15 beats per minute to meet the increased metabolic demands and higher cardiac output. **High-Yield NEET-PG Pearls:** * **Cardiac Output:** Increases by 30–50%, peaking at 28–32 weeks of gestation. * **Blood Pressure:** Systolic and diastolic BP decrease in the first and second trimesters (nadir at 20–24 weeks) due to decreased systemic vascular resistance (SVR), returning to pre-pregnancy levels by term. * **ECG Changes:** Besides LAD, you may see flattened or inverted T-waves in Lead III and Q-waves in Lead III and aVF (positional changes). * **Heart Sounds:** Loud S1 and a physiological S3 are common; S4 is rare and usually pathological.

Q: What is the approximate fetal weight if the height of the uterus above the pubic symphysis is 35 cm and the station of the head is -2?

3.5 kg. The correct answer is **3.5 kg**. ### **Explanation of the Correct Answer** The fetal weight is calculated using **Johnson’s Formula**, a clinical method to estimate fetal weight based on the fundal height and the station of the presenting part. **The Formula:** $\text{Fetal Weight (in grams)} = (H - n) \times 155$ Where: * **H** = Symphysio-fundal height (SFH) in cm. * **n** = 12 if the presenting part is at or above station 0. * **n** = 11 if the presenting part is below station 0 (engaged). **Calculation for this question:** * $H = 35 \text{ cm}$ * $n = 12$ (since the station is -2, which is above station 0) * $\text{Weight} = (35 - 12) \times 155$ * $\text{Weight} = 23 \times 155 = 3,565 \text{ grams} \approx \mathbf{3.5 \text{ kg}}$ ### **Why Other Options are Incorrect** * **Option A (2.5 kg):** This would correspond to an SFH of approximately 28 cm at station -2. * **Option B (3 kg):** This would correspond to an SFH of approximately 31-32 cm at station -2. * **Option D (4 kg):** This would require an SFH of approximately 38 cm at station -2. ### **High-Yield Clinical Pearls for NEET-PG** 1. **Rule of Thumb:** After 24 weeks of gestation, the SFH in centimeters roughly matches the gestational age in weeks (e.g., 30 cm $\approx$ 30 weeks). 2. **Haase’s Rule:** Used to determine fetal length. For the first 5 months, length = $\text{month}^2$. For the last 5 months, length = $\text{month} \times 5$. 3. **Limitations:** Johnson’s formula is less accurate in cases of maternal obesity, polyhydramnios, or multiple pregnancies. 4. **Station 0:** This refers to the level of the **ischial spines**. Any station with a negative value (-1 to -5) indicates the head is not yet engaged.

Q: What is the minimum height for a primigravida woman to be considered for intervention regarding fetal growth?

140 cm. **Explanation:** In obstetrics, maternal height is a critical screening tool used to predict the risk of **Cephalopelvic Disproportion (CPD)**. A short stature is often associated with a small or contracted pelvis, which can lead to obstructed labor, especially in a primigravida where the pelvis has not been "proven" by a previous delivery. 1. **Why 140 cm is correct:** According to standard obstetric guidelines (including WHO and Park’s Preventive and Social Medicine), a height of **less than 140–145 cm** is considered a high-risk factor. Specifically, for NEET-PG purposes, **140 cm** is the established threshold below which a primigravida is categorized as "short-statured," necessitating close monitoring for fetal growth and pelvic adequacy to prevent complications like obstructed labor. 2. **Why other options are incorrect:** * **145 cm:** While some guidelines use 145 cm as a cautionary cutoff, 140 cm is the more definitive "minimum" threshold used in most standardized Indian medical examinations to trigger intervention or high-risk classification. * **150 cm:** This is considered a normal height; women of this height generally have a lower risk of contracted pelvis. * **135 cm:** While a woman of this height is certainly at risk, the screening threshold starts higher (at 140 cm) to ensure early identification of at-risk mothers. **High-Yield Clinical Pearls for NEET-PG:** * **Contracted Pelvis:** Defined when any of the essential diameters of the pelvis is reduced by 0.5 cm or more. * **CPD Assessment:** The best clinical method to assess CPD is **Muller-Munro Kerr’s method** (bimanual examination). * **Complications of Short Stature:** Increased risk of non-engagement of the fetal head, malpresentations (e.g., transverse lie), and prolonged labor. * **Management:** Short-statured primigravidae should ideally deliver in a tertiary care center where facilities for an emergency Cesarean section are available.

Q: After an initial serum $\beta$-hCG test in a patient with suspected pregnancy, when should the repeat $\beta$-hCG level ideally be checked to assess viability or progression?

48 hours. ***Correct: 48 hours*** - In a viable, intrauterine pregnancy, serum β-hCG levels typically **double approximately every 48 hours** (or show a rise of at least 35% in 48 hours) during the initial weeks. - This standard **48-hour interval** is critical as it provides the most timely and appropriate benchmark to determine if the required doubling is occurring, aiding in the assessment of viability. - This is the **gold standard timing** for repeat β-hCG testing in early pregnancy monitoring. *Incorrect: 24 hours* - This interval is generally **too short** to observe the significant rise needed to confidently distinguish a normal, viable doubling rate from an abnormal or insufficient rate. - Due to natural variations in hormone secretion, a 24-hour reading often yields an overlapping range, making interpretation of the trend difficult. *Incorrect: 72 hours* - Although a check at 72 hours is sometimes used (as doubling can take up to 72 hours), waiting this long can **delay critical diagnosis** of urgent conditions like a non-ruptured **ectopic pregnancy** or ongoing miscarriage. - The 48-hour check remains the standard benchmark providing the earliest necessary data for management decisions. *Incorrect: 96 hours* - Waiting 96 hours (4 days) is generally **too long** and could significantly delay necessary intervention or further management for a non-viable or **ectopic pregnancy**. - While β-hCG doubling slows down significantly after approximately 6 weeks of gestation, the initial assessment requires the tighter 48-hour timeframe.

Q: A 24-year-old primigravida presents with painful vaginal bleeding in the first trimester. On USG, a well-formed gestation ring with central echoes from the embryo indicates a healthy fetus, and there is observation of fetal cardiac motion. What is the most probable diagnosis?

Threatened abortion. ***Threatened abortion***- This diagnosis applies when there is **vaginal bleeding** (often painful) in the first 20 weeks of pregnancy, but the **cervix is closed** and **fetal viability** (confirmed by fetal cardiac motion) is observed on ultrasound.- It is the most common cause of bleeding in early pregnancy and signifies that while the pregnancy is at risk, it is still continuing with a live fetus.*Inevitable abortion*- This diagnosis is characterized by vaginal bleeding accompanied by cervical changes, specifically **cervical dilation**, making continuation of the pregnancy unlikely.- Viable fetal cardiac activity rules out inevitable or ongoing abortion processes.*Incomplete abortion*- This involves the partial expulsion of the products of conception; USG would show **retained placental tissue** or fetal tissue and the loss of fetal viability.- The existence of **fetal cardiac motion** and a complete gestation ring confirms the pregnancy is still intact and rules out incomplete expulsion.*Complete abortion*- In this scenario, all products of conception have been expelled, resulting in an **empty uterine cavity** on ultrasound.- The presence of a **well-formed gestation ring** and an actively moving embryo/fetus clearly excludes complete abortion.

Question 1

Which of the following is NOT used for antenatal screening?

Accepted Answer

Peripheral lymphocytes

Answer

Cord blood

Answer

Amniotic fluid

Answer

Chorionic villi

Question 2

Which cardiovascular change is physiological in the last trimester of pregnancy?

Accepted Answer

Shift of apical impulse laterally and upwards in the left 4th intercostal space

Answer

Mid-diastolic murmur

Answer

Occasional atrial fibrillation

Answer

Cardiomegaly

Question 3

The double decidual sac sign (DDSS) is the best ultrasound method for diagnosing which of the following?

Accepted Answer

Normal intrauterine pregnancy

Answer

Monoamniotic Dichorionic twins

Answer

Diamniotic dichorionic twins

Answer

Ectopic pregnancy

Question 4

What is true about hematological changes in pregnancy?

Accepted Answer

Total blood volume increases by 40% by term.

Answer

The hematocrit increases.

Answer

Red cell volume does not increase until 20 weeks.

Answer

Hematocrit increases due to an increased RBC volume relative to plasma volume.

Question 5

What is a common cardiovascular change observed during pregnancy?

Accepted Answer

Slight left axis deviation in ECG

Answer

Slight right axis deviation in ECG

Answer

Diastolic murmur

Answer

Pulse rate is decreased

Question 6

What is the approximate fetal weight if the height of the uterus above the pubic symphysis is 35 cm and the station of the head is -2?

Accepted Answer

3.5 kg

Answer

2.5 kg

Answer

3 kg

Answer

4 kg

Question 7

What is uterine souffle?

Accepted Answer

Caused by an increase in blood flow through the dilated uterine vessels.

Answer

A soft blowing murmur synchronous with foetal heart sounds.

Answer

Caused by active foetal movements.

Answer

Indicates underlying foetal distress.

Question 8

What is the minimum height for a primigravida woman to be considered for intervention regarding fetal growth?

Accepted Answer

140 cm

Answer

145 cm

Answer

150 cm

Answer

135 cm

Question 9

After an initial serum $\beta$-hCG test in a patient with suspected pregnancy, when should the repeat $\beta$-hCG level ideally be checked to assess viability or progression?

Accepted Answer

48 hours

Answer

96 hours

Answer

24 hours

Answer

72 hours

Question 10

A 24-year-old primigravida presents with painful vaginal bleeding in the first trimester. On USG, a well-formed gestation ring with central echoes from the embryo indicates a healthy fetus, and there is observation of fetal cardiac motion. What is the most probable diagnosis?

Accepted Answer

Threatened abortion

Answer

Inevitable abortion

Answer

Complete abortion

Answer

Incomplete abortion

Prenatal Care — MCQs

Prenatal Care — MCQs

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