Prenatal Care Practice Questions

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

Tay-Sach's disease. **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.

Q: Definite diagnosis of pregnancy include all, except:

hCG in blood. ### 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.

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

46 days. **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).

Q: Which of the following is associated with Down syndrome?

Decreased AFP level. **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**.

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

25 mm. ### 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.

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

PAPP-A and beta HCG. **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.

Q: What is the optimal gestational age for pregnancy termination?

Second trimester. **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, **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.

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

8 to 9 days. ### 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**.

Q: 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?

Hegar's sign. **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.

Question 1

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

Accepted Answer

Tay-Sach's disease

Answer

Hemophilia A

Answer

Sickle cell disease

Answer

Duchenne muscular dystrophy

Question 2

Definite diagnosis of pregnancy include all, except:

Accepted Answer

hCG in blood

Answer

Fetal heart sound

Answer

Palpation of fetal parts

Answer

Fetal skeleton on X-ray

Question 3

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

Accepted Answer

46 days

Answer

35 days

Answer

38 days

Answer

53 days

Question 4

Which of the following is associated with Down syndrome?

Accepted Answer

Decreased AFP level

Answer

Raised PAPP-A level

Answer

Decreased beta-HCG level

Answer

Raised estriol level

Question 5

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

Accepted Answer

25 mm

Answer

15 mm

Answer

20 mm

Answer

30 mm

Question 6

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:

Accepted Answer

Send the patient to labor and delivery immediately for an emergency Cesarean section.

Answer

Allow the patient to undergo a vaginal breech delivery when she goes into labor.

Answer

Schedule a Cesarean section at or after 39 weeks gestation.

Answer

Schedule an external cephalic version in the next few days.

Question 7

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

Accepted Answer

PAPP-A and beta HCG

Answer

PAPP-A and estradiol

Answer

PAPP-A and AFP

Answer

Beta HCG and inhibin

Question 8

What is the optimal gestational age for pregnancy termination?

Accepted Answer

Second trimester

Answer

First trimester

Answer

Third trimester

Answer

None of the above

Question 9

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

Accepted Answer

8 to 9 days

Answer

3 to 4 days

Answer

12 to 14 days

Answer

20 to 21 days

Question 10

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?

Accepted Answer

Hegar's sign

Answer

Jacquemier's sign

Answer

Osiander's sign

Answer

Goodell's sign

Prenatal Care — MCQs

Prenatal Care — MCQs

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