Prenatal Care — MCQs

Prenatal Care Indian Medical PG Practice Questions and MCQs

Question 431: DNA analysis of chorionic villus sampling or amniocentesis is not likely to detect which of the following conditions?

A. Tay-Sach's disease (Correct Answer)
B. Hemophilia A
C. Sickle cell disease
D. Duchenne muscular dystrophy

Explanation: **Explanation:** The core concept tested here is the distinction between **genetic mutations** (detectable via DNA analysis) and **metabolic/enzymatic deficiencies** (traditionally detected via biochemical assays). **Why Tay-Sachs Disease is the correct answer:** Tay-Sachs disease is a lysosomal storage disorder caused by a deficiency of the enzyme **Hexosaminidase A**. While the underlying genetic mutation can technically be identified, the standard and most reliable prenatal diagnostic method for Tay-Sachs is the **biochemical assay of enzyme activity** rather than direct DNA analysis. This is because the disease exhibits significant genetic heterogeneity (many different mutations can lead to the same enzyme deficiency), making enzymatic levels a more definitive marker for diagnosis in a clinical setting. **Analysis of Incorrect Options:** * **Hemophilia A:** This is an X-linked recessive disorder caused by mutations in the Factor VIII gene. It is routinely diagnosed prenatally using DNA analysis (linkage analysis or direct mutation detection) from CVS or amniocentesis samples. * **Sickle Cell Disease:** This is a classic example of a single-point mutation (substitution of valine for glutamic acid). It is easily and definitively detected via DNA analysis (PCR or RFLP). * **Duchenne Muscular Dystrophy (DMD):** Caused by deletions or duplications in the Dystrophin gene, DMD is primarily diagnosed prenatally through DNA-based techniques like MLPA or PCR. **High-Yield Clinical Pearls for NEET-PG:** * **CVS Timing:** Performed at **10–13 weeks**. It cannot detect Neural Tube Defects (NTDs) as it doesn't measure AFP. * **Amniocentesis Timing:** Performed at **15–20 weeks**. * **Enzyme vs. DNA:** For metabolic disorders like Tay-Sachs or Gaucher’s, enzyme activity in cultured amniocytes or villi is the traditional "gold standard," whereas structural gene defects (Hemoglobinopathies, Muscular dystrophies) rely on DNA analysis.

Question 432: Definite diagnosis of pregnancy include all, except:

A. Fetal heart sound
B. Palpation of fetal parts
C. Fetal skeleton on X-ray
D. hCG in blood (Correct Answer)

Explanation: ### Explanation In Obstetrics, signs of pregnancy are categorized into **Presumptive**, **Probable**, and **Positive (Definite)** signs. Understanding this distinction is crucial for NEET-PG. **Why hCG in blood is the correct answer:** While the presence of Human Chorionic Gonadotropin (hCG) in blood or urine is a highly sensitive and reliable indicator of pregnancy, it is classified as a **Probable sign**, not a definite one. This is because hCG can be elevated in non-pregnancy conditions such as **Gestational Trophoblastic Neoplasia (Molar pregnancy)**, choriocarcinoma, or certain germ cell tumors (e.g., dysgerminoma). Therefore, it does not provide absolute proof of a live fetus. **Analysis of Incorrect Options (Definite Signs):** * **Fetal heart sound:** Detection of the fetal heartbeat (via Doppler at 10–12 weeks or Pinard stethoscope at 18–20 weeks) is an objective, absolute proof of a living fetus. * **Palpation of fetal parts:** Feeling distinct fetal movements or parts (limbs, trunk, head) by an examiner (usually after 20 weeks) is a positive sign. * **Fetal skeleton on X-ray:** Visualization of the fetal skeleton (detectable after 16 weeks due to ossification) is a definite sign. *Note: X-rays are generally avoided in modern practice due to radiation risks.* **High-Yield Clinical Pearls for NEET-PG:** 1. **Positive Signs of Pregnancy:** Fetal heart sounds, Palpation of fetal parts, Ultrasound visualization of the fetus, and Fetal movements felt by the clinician. 2. **Earliest Definite Sign:** Visualization of the gestational sac by Transvaginal Ultrasound (TVS) at **4.5 to 5 weeks**. 3. **Hegar’s Sign:** A probable sign involving softening of the lower uterine segment (6–10 weeks). 4. **Chadwick’s Sign:** A presumptive sign involving bluish discoloration of the cervix/vagina.

Question 433: Fetal heart can be detected earliest with trans-vaginal sonography at how many days from the last menstrual period?

A. 35 days
B. 38 days
C. 53 days
D. 46 days (Correct Answer)

Explanation: **Explanation:** The detection of fetal cardiac activity is a critical milestone in early pregnancy ultrasound. The correct answer is **46 days** (approximately 6.5 weeks) from the Last Menstrual Period (LMP). **Why 46 days is correct:** In a regular 28-day cycle, the fetal heart begins to beat at approximately 22 days after fertilization (5th week of gestation). However, clinical dating is calculated from the LMP. Using **Trans-vaginal Sonography (TVS)**, which has higher resolution than trans-abdominal routes, the fetal heart flicker is typically visible when the Crown-Rump Length (CRL) is 2–5 mm. This corresponds to a gestational age of **6 to 6.5 weeks (42–46 days)**. While some high-end machines detect it slightly earlier, 46 days is the standard clinical benchmark for consistent detection. **Analysis of Incorrect Options:** * **35 days (5 weeks):** At this stage, TVS usually only reveals the gestational sac and perhaps the yolk sac. The embryo is often too small for cardiac activity to be visualized. * **38 days (5.5 weeks):** This is the "transition" period. While a yolk sac is clearly seen, the heart tube is just beginning to pulsate and is frequently not visible on routine TVS. * **53 days (7.5 weeks):** By this time, the fetal heart is easily visible even on Trans-abdominal Sonography (TAS). This is too late to be considered the "earliest" detection point for TVS. **High-Yield Clinical Pearls for NEET-PG:** * **TVS vs. TAS:** TVS can detect fetal heart activity about **1 week earlier** than Trans-abdominal Sonography (which typically detects it at 7–8 weeks). * **Discriminatory CRL:** If the CRL is **>7 mm** and no cardiac activity is seen on TVS, it is diagnostic of pregnancy failure (missed abortion). * **Order of Appearance on TVS:** Gestational Sac (5 weeks) → Yolk Sac (5.5 weeks) → Fetal Pole with Heartbeat (6–6.5 weeks).

Question 434: Which of the following is associated with Down syndrome?

A. Raised PAPP-A level
B. Decreased beta-HCG level
C. Raised estriol level
D. Decreased AFP level (Correct Answer)

Explanation: **Explanation:** In Down syndrome (Trisomy 21), the maternal serum screening profile shows characteristic alterations in biochemical markers. The correct answer is **Decreased AFP level** because Alpha-fetoprotein (AFP), which is produced by the fetal liver and yolk sac, is typically lower than normal in pregnancies affected by Down syndrome. **Analysis of Options:** * **D. Decreased AFP level (Correct):** Low maternal serum AFP (MSAFP) is a classic marker for Trisomy 21. Conversely, elevated AFP is associated with neural tube defects or abdominal wall defects. * **A. Raised PAPP-A level (Incorrect):** In the first trimester, **Pregnancy-associated plasma protein A (PAPP-A)** is characteristically **decreased** in Down syndrome. * **B. Decreased beta-HCG level (Incorrect):** Free **beta-HCG** is significantly **elevated** in Down syndrome during both the first and second trimesters. * **C. Raised estriol level (Incorrect):** **Unconjugated estriol (uE3)** is **decreased** in Down syndrome. **High-Yield Clinical Pearls for NEET-PG:** To remember the markers for Down syndrome, focus on the **"HI"** rule: only **H**CG and **I**nhibin-A are **High** (elevated). All other markers (AFP, uE3, and PAPP-A) are low. * **Triple Test:** AFP (Low), uE3 (Low), hCG (High). * **Quadruple Test:** AFP (Low), uE3 (Low), hCG (High), Inhibin-A (High). * **First Trimester Screening:** PAPP-A (Low), beta-HCG (High), and increased Nuchal Translucency (NT). * **Edward Syndrome (Trisomy 18):** All markers (AFP, uE3, hCG) are typically **decreased**.

Question 435: At what size of mean gestational sac diameter measured on transvaginal sonography (TVS) with no embryonic pole is labeled as 'Anembryonic Gestation'?

A. 15 mm
B. 20 mm
C. 25 mm (Correct Answer)
D. 30 mm

Explanation: ### Explanation The diagnosis of early pregnancy failure is based on specific criteria established by the **Society of Radiologists in Ultrasound (SRU)** to avoid any risk of terminating a potentially viable pregnancy. **1. Why 25 mm is Correct:** An **Anembryonic Gestation** (formerly known as a "blighted ovum") is diagnosed when the **Mean Sac Diameter (MSD)** measures **≥ 25 mm** via Transvaginal Sonography (TVS) and contains no visible embryo (yolk sac or fetal pole). This threshold is set conservatively to ensure 100% specificity, as some viable pregnancies may not show an embryo at smaller diameters. **2. Analysis of Incorrect Options:** * **15 mm & 20 mm:** Historically, a threshold of 16–20 mm was used. However, these values were found to have a small margin of error (false positives). Current guidelines increased the limit to 25 mm to account for inter-observer variability. * **30 mm:** While a sac of 30 mm without an embryo is certainly non-viable, the diagnostic threshold is reached earlier at 25 mm. Waiting until 30 mm would unnecessarily delay management. **3. High-Yield Clinical Pearls for NEET-PG:** * **Crown-Rump Length (CRL) Criterion:** A diagnosis of pregnancy failure is also made if the CRL is **≥ 7 mm** with no visible cardiac activity on TVS. * **Yolk Sac Rule:** If a gestational sac is present but no yolk sac is seen, a follow-up scan in **2 weeks** is recommended. If a yolk sac is present but no embryo is seen, follow-up in **11 days** is required. * **Discriminatory Zone:** The serum β-hCG level at which a gestational sac should be visible on TVS is typically **1500–2000 mIU/mL**. * **Double Decidual Sign:** This is the earliest sign of an intrauterine pregnancy on ultrasound, distinguishing it from a pseudogestational sac seen in ectopic pregnancies.

Question 436: A 30-year-old G1P1001 patient presents at 37 weeks gestational age with a breech presentation. The cervix is 50% effaced and 1-2 cm dilated. The estimated fetal weight is 7 lbs. The patient is offered all the following management plans EXCEPT:

A. Allow the patient to undergo a vaginal breech delivery when she goes into labor.
B. Send the patient to labor and delivery immediately for an emergency Cesarean section. (Correct Answer)
C. Schedule a Cesarean section at or after 39 weeks gestation.
D. Schedule an external cephalic version in the next few days.

Explanation: ### Explanation The core concept in managing a breech presentation at term is balancing maternal-fetal risks while avoiding unnecessary emergency interventions in a stable patient. **Why Option B is the Correct Answer (The "Except" Option):** An **emergency Cesarean section** is not indicated in this scenario. The patient is currently at 37 weeks, stable, and not in active labor (cervix is only 1-2 cm dilated). Emergency surgery is reserved for acute maternal or fetal distress (e.g., cord prolapse, placental abruption, or non-reassuring fetal heart rate). Performing an immediate C-section at 37 weeks without a medical indication increases the risk of neonatal respiratory morbidity compared to waiting until 39 weeks. **Analysis of Other Options:** * **Option A:** Vaginal breech delivery is a valid option if specific criteria are met (e.g., frank breech, adequate pelvis, experienced clinician). While the Term Breech Trial favored C-sections, current ACOG/RCOG guidelines allow for planned vaginal delivery with informed consent. * **Option C:** If a C-section is chosen for breech presentation, it is ideally scheduled at **39 weeks** to ensure fetal lung maturity and reduce neonatal complications. * **Option D:** **External Cephalic Version (ECV)** is the preferred initial management for breech at term (≥37 weeks). Since she is currently 37 weeks and not in active labor, ECV can be attempted to convert the fetus to vertex. ### Clinical Pearls for NEET-PG: * **Timing of ECV:** Recommended at **37 weeks** in nulliparous and **36 weeks** in multiparous women. * **Prerequisites for Vaginal Breech:** Fetal weight between 2.5–4 kg, frank or complete breech (not footling), and a flexed fetal head. * **Most Common Breech:** Frank breech (buttocks presenting, hips flexed, knees extended). * **Risk of Cord Prolapse:** Highest in footling breech (~15%) and lowest in frank breech (~0.5%).

Question 437: Which tests are used for aneuploidy screening in the first trimester?

A. PAPP-A and estradiol
B. PAPP-A and AFP
C. PAPP-A and beta HCG (Correct Answer)
D. Beta HCG and inhibin

Explanation: **Explanation:** The **First Trimester Combined Screening** is the gold standard for aneuploidy screening (specifically Trisomy 21, 18, and 13) between **11 and 13+6 weeks** of gestation. It involves a combination of maternal serum markers and ultrasound findings. **1. Why Option C is Correct:** The two primary biochemical markers used are: * **PAPP-A (Pregnancy-Associated Plasma Protein A):** In pregnancies affected by Down Syndrome, PAPP-A levels are typically **decreased**. * **Free β-hCG (Human Chorionic Gonadotropin):** In Down Syndrome, β-hCG levels are typically **increased**. When combined with the ultrasound marker **Nuchal Translucency (NT)**, this screen achieves a detection rate of approximately 85–90%. **2. Why Other Options are Incorrect:** * **Option A & B:** **AFP (Alpha-Fetoprotein)** and **Estradiol (uE3)** are markers used in the **Second Trimester Quadruple Screen** (15–20 weeks). AFP is also used to screen for Neural Tube Defects (NTDs), which cannot be reliably screened via biochemistry in the first trimester. * **Option D:** **Inhibin-A** is the fourth component of the Second Trimester Quadruple Screen. It is not used for routine first-trimester screening. **3. High-Yield Clinical Pearls for NEET-PG:** * **Down Syndrome Profile (1st Trimester):** ↓ PAPP-A, ↑ β-hCG, ↑ Nuchal Translucency. * **Down Syndrome Profile (2nd Trimester/Quad Screen):** ↓ AFP, ↓ uE3, **↑ β-hCG, ↑ Inhibin-A** (Mnemonic: **HI**gh = **H**CG and **I**nhibin). * **Trisomy 18 (Edwards Syndrome):** All markers (PAPP-A, hCG, AFP, uE3) are generally **decreased**. * **Best Screening Tool:** Cell-free DNA (cfDNA/NIPT) has the highest sensitivity (>99%) but is more expensive.

Question 438: What is the optimal gestational age for pregnancy termination?

A. First trimester
B. Second trimester (Correct Answer)
C. Third trimester
D. None of the above

Explanation: **Explanation:** The question refers to the **optimal timing for termination of pregnancy in cases of severe maternal medical complications** (such as severe pre-eclampsia or cardiac disease) or **lethal fetal anomalies** where the goal is to balance maternal safety with the technical ease of the procedure. **Why the Second Trimester is correct:** In clinical practice and competitive exams, the second trimester (specifically between 13–20 weeks) is often considered the "optimal" window for elective or therapeutic termination when early diagnosis was missed. While first-trimester procedures are technically simpler, many structural anomalies and genetic markers are only detectable via mid-trimester scans (Level II ultrasound) or amniocentesis. Furthermore, modern induction protocols (using Misoprostol) make second-trimester termination highly effective with lower risks of uterine perforation compared to late-term surgical interventions. **Analysis of Incorrect Options:** * **First Trimester:** While safest for the mother (lowest complication rate), it is often too early to diagnose many major fetal structural malformations. * **Third Trimester:** This is the least optimal time. The fetus has reached viability, making termination ethically and legally complex (MTP Act restrictions). Surgically, it carries the highest risk of hemorrhage and uterine rupture. **High-Yield Clinical Pearls for NEET-PG:** * **MTP Act (India) Update:** Termination is now legal up to **24 weeks** for specific categories (survivors of sexual assault, minors, fetal anomalies). * **Method of Choice:** For <12 weeks, **Suction Evacuation** is preferred. For >12 weeks, **Medical Induction** (Misoprostol ± Mifepristone) or Dilatation & Evacuation (D&E) is used. * **Golden Rule:** The risk of maternal mortality increases by roughly 38% for each additional week of gestation beyond 8 weeks.

Question 439: With a sensitive test, hCG can be detected in maternal serum or urine how many days after ovulation?

A. 3 to 4 days
B. 8 to 9 days (Correct Answer)
C. 12 to 14 days
D. 20 to 21 days

Explanation: ### Explanation **1. Why Option B is Correct:** Human Chorionic Gonadotropin (hCG) is secreted by the **syncytiotrophoblast** only after successful implantation of the blastocyst. In a typical 28-day cycle, fertilization occurs in the ampulla of the fallopian tube shortly after ovulation. The zygote travels to the uterus and begins **implantation approximately 6 to 7 days after ovulation**. Once the blastocyst invades the endometrium, hCG enters the maternal circulation. Using highly sensitive assays (Immunoradiometric assay - IRMA), hCG can be detected in maternal serum as early as **8 to 9 days after ovulation**. **2. Analysis of Incorrect Options:** * **Option A (3 to 4 days):** At this stage, the conceptus is still a morula traveling through the fallopian tube. It has not yet implanted; therefore, no hCG is produced or released into the maternal system. * **Option C (12 to 14 days):** This corresponds to the time of the missed period. While standard home urine pregnancy tests (which require higher concentrations) often detect hCG at this point, sensitive serum tests can detect it much earlier. * **Option D (20 to 21 days):** This is well after implantation. By this time, hCG levels are rising rapidly, doubling every 48 hours. **3. Clinical Pearls for NEET-PG:** * **Doubling Time:** In early pregnancy, serum hCG levels double every **1.4 to 2 days**. * **Peak Levels:** hCG reaches its peak concentration (approx. 100,000 mIU/mL) at **8 to 10 weeks** of gestation, then declines to a plateau. * **Subunits:** hCG is a glycoprotein with alpha and beta subunits. The **beta (β) subunit** is unique and used for pregnancy testing to avoid cross-reactivity with LH, FSH, and TSH (which share the same alpha subunit). * **Discriminatory Zone:** The level of hCG at which a gestational sac should be visible on TVS is **1500–2000 mIU/mL**.

Question 440: Which of the following signs during early pregnancy is characterized by an enlarged upper part of the uterus, a soft lower part of the body, and a firm cervix?

A. Hegar's sign (Correct Answer)
B. Jacquemier's sign
C. Osiander's sign
D. Goodell's sign

Explanation: **Explanation:** The correct answer is **Hegar's sign**. This is a clinical sign of early pregnancy, typically detectable between **6 to 10 weeks** of gestation. It is characterized by the softening of the lower uterine segment (isthmus). During a bimanual examination, the upper part of the uterus feels enlarged and elastic (due to the growing fetus), the cervix feels relatively firm, and the intervening lower segment feels so soft and empty that the fingers of the internal and external hands seem to meet. **Analysis of Incorrect Options:** * **B. Jacquemier's sign (Chadwick’s sign):** This refers to the bluish discoloration of the vestibule and anterior vaginal wall due to increased vascularity. It appears around 8 weeks. * **C. Osiander's sign:** This is the detection of increased pulsations felt through the lateral vaginal fornices, caused by increased vascularity of the uterine arteries. * **D. Goodell's sign:** This refers specifically to the softening of the **cervix** (often described as feeling like the "lips" rather than the "nose"). It typically appears around 6 weeks. **High-Yield Clinical Pearls for NEET-PG:** * **Palmer’s Sign:** Regular, rhythmic uterine contractions felt during a bimanual examination (4–8 weeks). * **Piskacek’s Sign:** Asymmetrical enlargement of the uterus if implantation occurs near one of the cornua. * **Ladins Sign:** Softening of the anterior midline of the uterus at the junction with the cervix (6 weeks). * **Von Fernwald’s Sign:** Irregular softening of the fundus over the site of implantation.

Practice by Chapter

Preconception Counseling

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Pregnancy Diagnosis and Dating

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Routine Antenatal Assessments

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Maternal Physiological Changes

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Nutrition in Pregnancy

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Screening Tests in Pregnancy

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Fetal Growth Assessment

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High-Risk Pregnancy Identification

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Antenatal Complications Management

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Psychosocial Aspects of Pregnancy

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