Prenatal Care — MCQs

Prenatal Care Indian Medical PG Practice Questions and MCQs

Question 441: What is the single most important feature for diagnosing fetal aneuploidy?

A. Increased nuchal translucency (Correct Answer)
B. Absent nasal bone
C. Cystic hygroma
D. Abnormal ductus venosus flow

Explanation: **Explanation:** **Increased Nuchal Translucency (NT)** is the single most important and sensitive ultrasound marker for fetal aneuploidy, particularly Trisomy 21 (Down Syndrome), in the first trimester (11–13+6 weeks). It refers to the subcutaneous collection of fluid behind the fetal neck. An NT measurement ≥3.5 mm or above the 95th percentile for gestational age is highly predictive of chromosomal abnormalities, structural heart defects, and various genetic syndromes. **Analysis of Options:** * **B. Absent Nasal Bone:** While a powerful marker (absent in ~60-70% of Trisomy 21 fetuses), it is considered a secondary marker. It increases the likelihood ratio but is less sensitive as a standalone screening tool compared to NT. * **C. Cystic Hygroma:** This is a more severe malformation of the lymphatic system. While strongly associated with Turner Syndrome and Trisomy 21, it is less common than increased NT and often represents a later or more pathological stage of fluid accumulation. * **D. Abnormal Ductus Venosus (DV) Flow:** Reversed a-wave in the DV is a significant marker for aneuploidy and cardiac defects, but like the nasal bone, it is used to "fine-tune" the risk calculated primarily by NT and maternal age. **High-Yield Clinical Pearls for NEET-PG:** * **Optimal Timing:** NT must be measured when the Crown-Rump Length (CRL) is between **45 mm and 84 mm**. * **Combined Test:** The gold standard first-trimester screening includes **NT + PAPP-A + free β-hCG**, which has a detection rate of ~90% for Down Syndrome. * **Next Step:** If NT is increased, the next step is **CVS (Chorionic Villus Sampling)** for definitive karyotyping or NIPT for further screening. * **Association:** Increased NT with a *normal* karyotype should prompt a **Fetal Echocardiography** at 18–22 weeks to rule out cardiac anomalies.

Question 442: What is the normal net weight gain during pregnancy?

A. 11 Pounds
B. 24 Pounds (Correct Answer)
C. 36 Pounds
D. 42 Pounds

Explanation: The normal net weight gain during a singleton pregnancy for a woman with a normal pre-pregnancy BMI (18.5–24.9 kg/m²) is approximately **11 kg**, which converts to roughly **24 pounds** (1 kg ≈ 2.2 lbs). ### **Medical Concept & Distribution** The total weight gain is a combination of the "products of conception" and maternal physiological adaptations. The average distribution is as follows: * **Fetus:** ~7.5 lbs (3.4 kg) * **Placenta/Amniotic Fluid:** ~3.5 lbs (1.6 kg) * **Uterus/Breasts:** ~4 lbs (1.8 kg) * **Blood/Fluid Volume:** ~6 lbs (2.7 kg) * **Maternal Fat Stores:** ~3–4 lbs (1.5 kg) **Total:** ~24–25 lbs. ### **Analysis of Options** * **Option A (11 Pounds):** This is significantly underweight. While 11 **kg** is the correct metric value, 11 **pounds** is insufficient and associated with Intrauterine Growth Restriction (IUGR). * **Option C (36 Pounds):** This represents the upper limit of the IOM (Institute of Medicine) guidelines (25–35 lbs). While common, it is not the "standard" net average often tested in classical textbooks. * **Option D (42 Pounds):** This indicates excessive weight gain, increasing the risk of gestational diabetes, macrosomia, and postpartum weight retention. ### **High-Yield Clinical Pearls for NEET-PG** 1. **BMI-Based Recommendations:** * Underweight (<18.5): 28–40 lbs * Normal (18.5–24.9): 25–35 lbs * Overweight (25–29.9): 15–25 lbs * Obese (>30): 11–20 lbs 2. **Rate of Gain:** In the 2nd and 3rd trimesters, a woman with a normal BMI should gain approximately **1 lb (0.5 kg) per week**. 3. **Sudden Weight Gain:** A gain of >2 kg/month is a warning sign for **Pre-eclampsia** (due to fluid retention).

Question 443: What is the earliest structure detectable for pregnancy by ultrasound?

A. Gestational sac (Correct Answer)
B. Fetal pole
C. Follicle-stimulating hormone (FSH)
D. Fetal skeleton

Explanation: **Explanation:** The detection of pregnancy via ultrasound follows a predictable chronological sequence based on embryonic development. **1. Why Gestational Sac is correct:** The **gestational sac** is the first definitive sonographic sign of pregnancy. It can be visualized using Transvaginal Sonography (TVS) as early as **4.5 to 5 weeks** of gestation (when the Mean Sac Diameter is approximately 2–3 mm). It appears as a small fluid collection surrounded by an echogenic rim (the decidual reaction) within the endometrial cavity. **2. Why the other options are incorrect:** * **Fetal pole:** This is the thickening on the margin of the yolk sac that represents the early embryo. It appears after the gestational sac and yolk sac, typically at **5.5 to 6 weeks** via TVS. * **Follicle-stimulating hormone (FSH):** FSH is a pituitary hormone involved in the menstrual cycle, not a structure used to detect pregnancy. In fact, FSH levels are suppressed during pregnancy due to high levels of estrogen and progesterone. * **Fetal skeleton:** This is a late finding. Mineralization of the fetal skeleton begins around the 8th week, but it is generally not clearly visible on routine ultrasound until the **second trimester** (after 12–14 weeks). **High-Yield Clinical Pearls for NEET-PG:** * **Order of appearance (TVS):** Gestational Sac (4.5–5 wks) → Yolk Sac (5.5 wks) → Fetal Pole/Cardiac activity (6 wks). * **Discriminatory Zone:** The level of serum β-hCG at which a gestational sac should be visible. For TVS, this is typically **1,500–2,000 mIU/mL**. * **Double Decidual Sign:** A useful sonographic feature to distinguish a true gestational sac from a "pseudogestational sac" seen in ectopic pregnancies.

Question 444: Sex determination in early pregnancy is done by:

A. X-rays
B. Amniocentesis
C. Ultrasound (Correct Answer)
D. Hysteroscopy

Explanation: **Explanation:** **Correct Option: C. Ultrasound** Ultrasound (USG) is the primary, non-invasive modality used for sex determination in clinical practice. While chromosomal sex is determined at fertilization, the external genitalia become sonographically distinguishable starting from the **12th–14th week** of gestation. By the second trimester (18–22 weeks), the accuracy of USG for sex determination reaches nearly 100% by identifying the "phallus" in males or the "labial folds" (hamburger sign) in females. **Incorrect Options:** * **A. X-rays:** These are contraindicated in early pregnancy due to the risk of teratogenicity and fetal radiation. Furthermore, X-rays only visualize calcified fetal bones and cannot differentiate soft tissue genitalia. * **B. Amniocentesis:** While amniocentesis (karyotyping) is the "gold standard" for definitive genetic sex determination, it is an **invasive** procedure. It is performed for genetic screening (e.g., Down syndrome), not for routine sex determination. * **D. Hysteroscopy:** This is an endoscopic procedure used to visualize the uterine cavity in non-pregnant women. It is not used during pregnancy as it would disrupt the gestational sac. **High-Yield Clinical Pearls for NEET-PG:** * **PCPNDT Act:** In India, the Pre-Conception and Pre-Natal Diagnostic Techniques Act strictly prohibits the disclosure of fetal sex to prevent female feticide. * **Earliest Method:** Non-Invasive Prenatal Testing (NIPT), which analyzes **cell-free fetal DNA (cffDNA)** in maternal blood, can determine fetal sex as early as **7–9 weeks**, though USG remains the most common method. * **The "Angle of the Genital Tubercle":** In the first trimester (11–13 weeks), a cranial orientation of the genital tubercle (>30°) suggests a male, while a caudal orientation (<10°) suggests a female.

Question 445: At what gestational age does an expectant mother typically feel quickening?

A. 12-18 weeks
B. 16-20 weeks (Correct Answer)
C. 26 weeks
D. 24-28 weeks

Explanation: **Explanation:** **Quickening** refers to the first perception of fetal movements by the mother. It is a subjective clinical milestone used to corroborate gestational age. **Why 16–20 weeks is correct:** The timing of quickening depends primarily on the mother's parity: * **Multigravida:** Women who have been pregnant before typically feel movements earlier, around **16–18 weeks**, because they are familiar with the sensation. * **Primigravida:** First-time mothers usually perceive movement later, around **18–20 weeks**, often mistaking early movements for intestinal gas or peristalsis. The range of 16–20 weeks encompasses both groups, making it the most accurate clinical window. **Analysis of Incorrect Options:** * **A (12–18 weeks):** While the fetus begins moving as early as 7–8 weeks (visible on ultrasound), the mother cannot feel these movements through the uterine wall at 12 weeks. * **C (26 weeks) & D (24–28 weeks):** These are far too late. By 24–28 weeks, fetal movements are vigorous and can often be felt by an external examiner (palpation). **NEET-PG High-Yield Pearls:** * **Clinical Significance:** Quickening is a subjective sign of pregnancy. If a mother does not feel movements by 20 weeks, an ultrasound is indicated to confirm fetal viability. * **Daily Fetal Movement Count (DFMC):** While quickening marks the *start* of perception, formal monitoring (e.g., Cardiff "Count to Ten" chart) is usually advised only after **28 weeks**. * **Factors delaying perception:** Obesity, posterior placenta, and polyhydramnios can make quickening more difficult to perceive early on.

Question 446: Which of the following is NOT used for antenatal screening?

A. Cord blood
B. Amniotic fluid
C. Chorionic villi
D. Peripheral lymphocytes (Correct Answer)

Explanation: **Explanation:** Antenatal screening and diagnosis aim to identify genetic or chromosomal abnormalities in the fetus. The fundamental requirement for these tests is the acquisition of **fetal genetic material**. **Why Peripheral Lymphocytes is the correct answer:** Peripheral lymphocytes are obtained from the **mother’s venous blood**. While maternal blood contains maternal DNA, it does not provide a direct source of fetal cells for traditional karyotyping or chromosomal analysis. Although "Cell-Free Fetal DNA" (cffDNA) can be found in maternal plasma, it consists of fragmented DNA from the placenta, not intact fetal lymphocytes. Therefore, maternal peripheral lymphocytes reflect the mother's genetic makeup, not the fetus's, making them unsuitable for antenatal screening of the child. **Analysis of Incorrect Options:** * **Amniotic Fluid:** Obtained via **Amniocentesis** (usually 15–20 weeks). It contains desquamated fetal cells (amniocytes) used for karyotyping, biochemical analysis (AFP), and DNA studies. * **Chorionic Villi:** Obtained via **Chorionic Villus Sampling (CVS)** (usually 10–13 weeks). These are placental tissues derived from the trophoblast, sharing the same genetic constitution as the fetus. * **Cord Blood:** Obtained via **Percutaneous Umbilical Blood Sampling (PUBS)** or Cordocentesis (usually after 18 weeks). This provides direct access to fetal blood cells for rapid karyotyping and assessing fetal anemia or infections. **Clinical Pearls for NEET-PG:** * **Gold Standard for Karyotyping:** Amniocentesis is the most common invasive diagnostic procedure. * **Earliest Invasive Test:** CVS can be performed earlier than amniocentesis. * **Non-Invasive Prenatal Testing (NIPT):** Uses maternal blood to screen for trisomies by analyzing **cffDNA**, but this is different from testing maternal lymphocytes. * **Confined Placental Mosaicism:** A potential pitfall of CVS where the placenta and fetus have different genetic makeups.

Question 447: Which of the following is NOT a presumptive sign of pregnancy?

A. Jacquemier's sign
B. Dalrymple sign (Correct Answer)
C. Hegar's sign
D. Palmer's sign

Explanation: To master pregnancy diagnosis for NEET-PG, it is essential to distinguish between **Presumptive, Probable, and Positive** signs. **Why Dalrymple sign is the correct answer:** Dalrymple sign refers to the widening of the palpebral fissures (staring look) seen in **Graves' ophthalmopathy** (hyperthyroidism). It has no clinical association with pregnancy. Therefore, it is the "odd one out." **Analysis of Incorrect Options (Probable Signs):** While the question asks for "Presumptive" signs, the options provided (A, C, and D) are actually classified as **Probable signs** (objective findings by an examiner, usually related to the uterus/cervix). In many exams, the distinction is made between "signs of pregnancy" and "non-pregnancy signs." * **Jacquemier’s sign (Chadwick’s sign):** Bluish discoloration of the anterior vaginal wall/cervix due to pelvic congestion (seen at 6–8 weeks). * **Hegar’s sign:** Softening of the lower uterine segment, allowing the fingers of the internal and external hands to meet on bimanual examination (seen at 6–10 weeks). * **Palmer’s sign:** Regular, rhythmic, painless uterine contractions felt during pelvic examination (seen as early as 4–8 weeks). **High-Yield Clinical Pearls for NEET-PG:** 1. **Presumptive signs (Subjective):** Amenorrhea, morning sickness, breast tenderness, and quickening. 2. **Probable signs (Objective):** Hegar’s, Goodell’s (softening of cervix), Piskacek’s (asymmetrical enlargement), and Osiander’s (pulsations in lateral fornix) signs. 3. **Positive signs (Diagnostic):** Fetal heart sounds (Doppler at 10 weeks), fetal movements felt by the clinician, and ultrasound evidence of a gestational sac. 4. **Quickening:** Usually felt at 18–20 weeks in primigravida and 16–18 weeks in multigravida.

Question 448: Down's syndrome is due to:

A. 5/12 translocation
B. Trisomy 18
C. Trisomy 21 (Correct Answer)
D. 14/21 translocation

Explanation: **Explanation:** Down’s syndrome (Trisomy 21) is the most common autosomal trisomy in live births. It occurs due to the presence of an extra copy of chromosome 21. **1. Why Trisomy 21 is correct:** In approximately **95% of cases**, Down’s syndrome is caused by **meiotic non-disjunction**, where chromosomes fail to separate during gametogenesis (most commonly during maternal meiosis I). This results in a karyotype of 47,XX,+21 or 47,XY,+21. The remaining cases are due to Robertsonian translocations (approx. 4%) or mosaicism (approx. 1%). **2. Analysis of Incorrect Options:** * **Option A (5/12 translocation):** This is not a recognized cause of Down’s syndrome. Deletion of the short arm of chromosome 5 (5p-) leads to **Cri-du-chat syndrome**. * **Option B (Trisomy 18):** This causes **Edwards syndrome**, characterized by clenched fists with overlapping fingers, rocker-bottom feet, and micrognathia. * **Option D (14/21 translocation):** While Robertsonian translocations involving chromosome 21 can cause Down’s syndrome, the question asks for the primary etiology. Trisomy 21 (non-disjunction) is the definitive cause in the vast majority of cases. Note: A **21/21 translocation** carrier has a 100% risk of having a child with Down’s syndrome. **NEET-PG High-Yield Pearls:** * **Risk Factor:** Increasing maternal age is the strongest risk factor for non-disjunction. * **First Trimester Screening:** Combined test (Nuchal Translucency + PAPP-A + free β-hCG) at 11–13+6 weeks. * **Quadruple Test (Second Trimester):** Low AFP, Low Unconjugated Estriol (uE3), **High hCG**, and **High Inhibin-A** (Mnemonic: **HI**gh = **H**CG and **I**nhibin). * **Most common cardiac defect:** Atrioventricular Septal Defect (Endocardial cushion defect).

Question 449: At how many weeks of gestation can Hegar's sign be elicited?

A. 8 weeks (Correct Answer)
B. 10 weeks
C. 12 weeks
D. 15 weeks

Explanation: **Explanation:** **Hegar’s sign** is a clinical indicator of early pregnancy characterized by the softening of the **isthmus** (the lower part of the uterus just above the cervix). On bimanual examination, the isthmus feels so soft and empty that the body of the uterus and the cervix may feel like two separate structures. 1. **Why 8 weeks is correct:** Hegar’s sign typically becomes detectable between **6 to 10 weeks** of gestation. At **8 weeks**, the softening is most pronounced and classically elicited. This occurs due to increased vascularity and pelvic congestion (influenced by estrogen and progesterone) specifically affecting the thin-walled isthmus. 2. **Why other options are incorrect:** * **10 weeks:** While it may still be present, it is usually first clearly identifiable by the 6th–8th week. * **12 weeks:** By the end of the first trimester, the uterus becomes more globular and rises out of the pelvis, making this specific sign less distinct as the isthmus begins to incorporate into the expanding uterine body. * **15 weeks:** This is well into the second trimester; by this stage, the sign is no longer relevant as the uterus is an abdominal organ. **High-Yield Clinical Pearls for NEET-PG:** * **Goodell’s Sign:** Softening of the cervix (feels like the lips instead of the tip of the nose), usually seen at **6 weeks**. * **Chadwick’s Sign:** Bluish discoloration of the cervix and vagina due to increased vascularity, seen at **6–8 weeks**. * **Piskacek’s Sign:** Asymmetrical enlargement of the uterus if implantation occurs near one of the cornua. * **Palmer’s Sign:** Rhythmic uterine contractions felt during bimanual examination as early as **4–8 weeks**.

Question 450: Which of the following is the investigation of choice in a pregnant lady at 18 weeks of gestation with a past history of delivering a baby with Down's syndrome?

A. Triple screen test
B. Amniocentesis (Correct Answer)
C. Chorionic villus sampling
D. Ultrasonography

Explanation: **Explanation:** The core concept here is distinguishing between **screening** and **diagnostic** tests. A woman with a prior history of a child with Down syndrome is at a significantly higher risk for recurrence. Therefore, she requires a definitive diagnostic test rather than a screening test. **1. Why Amniocentesis is the Correct Answer:** Amniocentesis is the **investigation of choice** for chromosomal analysis (karyotyping) when the patient is in the second trimester (typically performed between 15–20 weeks). Since this patient is at **18 weeks**, amniocentesis is the most appropriate diagnostic procedure to confirm or rule out trisomy 21. **2. Why other options are incorrect:** * **Triple Screen Test (Option A):** This is a screening test (measuring AFP, hCG, and uE3). In a high-risk patient with a prior history, screening is bypassed in favor of definitive diagnosis. * **Chorionic Villus Sampling (Option C):** While CVS is a diagnostic test, it is ideally performed between **10–13 weeks** (first trimester). At 18 weeks, the placenta is more developed, and the risk-benefit ratio favors amniocentesis. * **Ultrasonography (Option D):** USG can identify "soft markers" (like nuchal fold thickness), but it is not a definitive diagnostic tool for Down syndrome. **Clinical Pearls for NEET-PG:** * **Timing is Key:** CVS (10–13 weeks), Amniocentesis (15–20 weeks), Cordocentesis (>20 weeks). * **Gold Standard:** Karyotyping via amniocentesis remains the gold standard for diagnosing chromosomal aneuploidies in the second trimester. * **Risk of Loss:** The procedure-related pregnancy loss for amniocentesis is approximately 0.5% (1 in 200). * **Recurrence Risk:** The risk of Down syndrome in a subsequent pregnancy after one affected child is approximately 1% or the age-related risk, whichever is higher.

Practice by Chapter

Preconception Counseling

Practice Questions

Pregnancy Diagnosis and Dating

Practice Questions

Routine Antenatal Assessments

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Maternal Physiological Changes

Practice Questions

Nutrition in Pregnancy

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Screening Tests in Pregnancy

Practice Questions

Fetal Growth Assessment

Practice Questions

High-Risk Pregnancy Identification

Practice Questions

Antenatal Complications Management

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Psychosocial Aspects of Pregnancy

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