Prenatal Care Practice Questions

Q: Maternal serum Alpha-fetoprotein is raised in all the following conditions EXCEPT?

Down's syndrome. **Explanation:** Maternal Serum Alpha-Fetoprotein (MSAFP) is a glycoprotein produced initially by the yolk sac and later by the fetal liver. It enters the maternal circulation via the placenta and amniotic fluid. **Why Down’s Syndrome is the Correct Answer:** In **Down’s Syndrome (Trisomy 21)**, MSAFP levels are characteristically **decreased** (usually <0.5 MoM), not raised. This is often associated with decreased levels of Unconjugated Estriol (uE3) and increased levels of hCG and Inhibin-A (the "Quadruple Test" profile). **Analysis of Incorrect Options (Conditions with Raised MSAFP):** * **Spina Bifida (Open Neural Tube Defects):** AFP leaks directly from the exposed fetal tissues into the amniotic fluid and subsequently into the maternal serum. * **Multiple Pregnancy:** Since AFP is produced by the fetus, multiple fetuses result in higher cumulative levels of AFP in the maternal blood. * **Omphalocele (Abdominal Wall Defects):** Similar to NTDs, the lack of skin integrity allows AFP to leak into the amniotic fluid, leading to elevated maternal levels. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most Common Cause of Raised MSAFP:** Underestimation of gestational age (wrong dates). 2. **Raised MSAFP (>2.5 MoM):** Seen in NTDs, abdominal wall defects (Gastroschisis > Omphalocele), multiple gestations, fetal demise, and renal anomalies (Finnish-type nephrosis). 3. **Low MSAFP (<0.5 MoM):** Seen in Down’s syndrome, Trisomy 18 (Edwards syndrome), gestational trophoblastic disease, and maternal obesity. 4. **Screening Window:** The ideal time for MSAFP screening is **15–20 weeks** of gestation.

Q: Normally, what is the upper limit for Nuchal Translucency measurement?

Less than 3 mm. **Explanation:** **Nuchal Translucency (NT)** is the sonographic appearance of a collection of fluid under the skin behind the fetal neck in the first trimester. It is a critical screening marker for chromosomal abnormalities and structural defects. **1. Why "Less than 3 mm" is correct:** In clinical practice and standardized screening protocols (Fetal Medicine Foundation), the 95th percentile for NT thickness is approximately 2.5 mm, while the **99th percentile is 3.5 mm**. For the purpose of competitive exams like NEET-PG, **3 mm** is generally accepted as the upper limit of normal. A measurement ** 3.5 mm) is considered increased and warrants further diagnostic testing (CVS or Amniocentesis). **2. Why other options are incorrect:** * **Options A & D (> 10 mm and > 5 mm):** These values are significantly pathological. An NT > 3.5 mm is associated with a high risk of Trisomy 21 (Down Syndrome), Trisomy 18, Trisomy 13, and Turner Syndrome. * **Option B (< 6 mm):** This threshold is too high. Using 6 mm as a cutoff would result in a dangerously high false-negative rate, missing the majority of chromosomal anomalies. **3. High-Yield Clinical Pearls for NEET-PG:** * **Timing:** NT must be measured between **11 weeks and 13 weeks 6 days** of gestation. * **CRL Criteria:** The Fetal Crown-Rump Length (CRL) must be between **45 mm and 84 mm**. * **Associated Conditions:** Increased NT is not only seen in aneuploidies but is also a strong marker for **Congenital Heart Disease** (most common), diaphragmatic hernia, and skeletal dysplasias. * **Combined Test:** NT is used along with maternal age and biochemical markers (**PAPP-A and β-hCG**) to calculate the risk for Down Syndrome.

Q: Fetal cardiac activity is detected with transvaginal ultrasound as early as which gestational age?

6 weeks. **Explanation:** The detection of fetal cardiac activity is a critical milestone in early pregnancy assessment. On **Transvaginal Sonography (TVS)**, the fetal heart pole and cardiac flicker can typically be visualized when the Crown-Rump Length (CRL) is 2–5 mm, which corresponds to approximately **6 weeks of gestation**. * **Why 6 weeks is correct:** Embryonic heart development begins early, but it reaches a size and rate detectable by high-frequency TVS probes by the 6th week. In a normal intrauterine pregnancy, cardiac activity must be seen once the CRL reaches 7 mm; failure to do so is a diagnostic criterion for pregnancy failure. * **Why 8 weeks is incorrect:** While cardiac activity is clearly visible and the heart is fully formed by 8 weeks, it can be detected much earlier via TVS. 8 weeks is more characteristic of detection via older, less sensitive transabdominal probes. * **Why 10 & 12 weeks are incorrect:** These represent later stages of the first trimester. By 10–12 weeks, fetal heart tones can typically be heard using a **Handheld Doppler**, but ultrasound detection occurs much earlier. **High-Yield Clinical Pearls for NEET-PG:** 1. **TVS vs. TAS:** TVS can detect pregnancy milestones about **1 week earlier** than Transabdominal Sonography (TAS). 2. **Sequence of TVS findings:** * **Gestational Sac:** 4.5 – 5 weeks (Mean Sac Diameter >25mm without embryo = Blighted ovum). * **Yolk Sac:** 5 – 5.5 weeks (First sign of an intrauterine pregnancy). * **Cardiac Activity:** 6 – 6.5 weeks. 3. **Discriminatory Zone:** The β-hCG level at which a gestational sac should be visible on TVS is **1500–2000 mIU/ml**.

Q: Prophylactic anti-D immunoglobulin is given to Rh-negative pregnant women antenatally at which gestational age?

28 weeks. **Explanation:** The correct answer is **28 weeks (Option C)**. **Medical Concept:** Rh isoimmunization occurs when an Rh-negative mother is exposed to Rh-positive fetal red blood cells, leading to the production of anti-D antibodies. While most feto-maternal hemorrhages (FMH) occur at delivery, small "silent" bleeds can occur during the third trimester. Prophylactic administration of Anti-D immunoglobulin (RhoGAM) at **28 weeks** of gestation is the standard of care because the risk of sensitization increases significantly after this period. A single dose of 300 mcg (1500 IU) at 28 weeks provides coverage for the remainder of the pregnancy, as the half-life of the immunoglobulin is approximately 24 days. **Analysis of Incorrect Options:** * **A (20 weeks) & B (24 weeks):** These are too early. The risk of spontaneous FMH in an uncomplicated pregnancy is negligible before 28 weeks. Administering it this early would mean the passive antibodies would deplete before the high-risk delivery period. * **D (32 weeks):** This is too late. A significant number of women may already become sensitized between 28 and 32 weeks, rendering the prophylaxis ineffective if delayed. **High-Yield Clinical Pearls for NEET-PG:** * **Postpartum Dose:** If the neonate is Rh-positive, a second dose (300 mcg) must be given within **72 hours of delivery**. * **First Trimester Events:** For miscarriage, ectopic pregnancy, or CVS (<13 weeks), a lower dose of **50 mcg** is sufficient. * **Indirect Coombs Test (ICT):** Anti-D is only given if the mother is **non-sensitized** (ICT negative). If ICT is positive, the mother is already sensitized, and Anti-D is of no use. * **Kleihauer-Betke Test:** Used to quantify the volume of FMH to determine if additional doses of Anti-D are required beyond the standard 300 mcg.

Q: A hypertensive woman is seeking preconception counseling. Which of the following antihypertensive medications is advised to be continued once she becomes pregnant?

Nifedipine. **Explanation:** The management of hypertension in pregnancy requires a careful balance between maternal benefit and fetal safety. **Nifedipine**, a long-acting Calcium Channel Blocker (CCB), is considered a first-line antihypertensive agent in pregnancy. It is preferred because it is non-teratogenic, does not affect uteroplacental blood flow significantly, and has a well-established safety profile for both chronic hypertension and the management of pre-eclampsia. **Analysis of Options:** * **Nifedipine (Correct):** Along with Labetalol and Methyldopa, Nifedipine is a mainstay of treatment. It is effective and safe to continue from the preconception period through delivery. * **Enalapril (Incorrect):** This is an ACE Inhibitor. ACE inhibitors are strictly contraindicated in pregnancy (Category D) as they cause **fetal renal dysgenesis**, oligohydramnios, skull hypoplasia, and intrauterine growth restriction (IUGR). * **Losartan (Incorrect):** This is an Angiotensin II Receptor Blocker (ARB). Like ACE inhibitors, ARBs interfere with the fetal renin-angiotensin system, leading to severe renal toxicity and fetopathy. * **Chlorthalidone (Incorrect):** Thiazide diuretics are generally avoided as first-line therapy in pregnancy because they can prevent the physiological plasma volume expansion necessary for a healthy pregnancy and may cause neonatal thrombocytopenia or electrolyte imbalances. **High-Yield NEET-PG Pearls:** * **Drug of Choice (DOC)** for Chronic Hypertension in pregnancy: **Labetalol** (often preferred over Methyldopa due to fewer side effects). * **DOC for Acute Hypertensive Crisis** in pregnancy: **IV Labetalol** or **IV Hydralazine**. * **Safe drugs:** Labetalol, Methyldopa, Nifedipine, Hydralazine. * **Contraindicated drugs:** ACE inhibitors, ARBs, Nitroprusside (risk of cyanide toxicity), and Spironolactone (anti-androgenic effects).

Q: In triple screening test for Down's syndrome during pregnancy, which of the following is NOT included?

Acetyl cholinesterase. ### Explanation The **Triple Screening Test** is a second-trimester maternal serum screening performed between **15 and 20 weeks** of gestation (ideally 16–18 weeks) to assess the risk of chromosomal abnormalities, primarily Down syndrome (Trisomy 21). #### Why Acetylcholinesterase is the Correct Answer **Acetylcholinesterase (AChE)** is not a component of the Triple Screen. It is a specific biochemical marker used to confirm **Neural Tube Defects (NTDs)**. When Maternal Serum Alpha-Fetoprotein (MSAFP) is elevated, an amniocentesis is performed; if the amniotic fluid AFP is also high, the presence of AChE in the amniotic fluid confirms an open NTD (like spina bifida or anencephaly), as it leaks from exposed neural tissue. #### Analysis of Incorrect Options (Components of Triple Screen) In a pregnancy affected by **Down Syndrome**, the typical "Triple Test" pattern is: * **Maternal Serum Alpha-fetoprotein (MSAFP):** Decreased. * **Serum Unconjugated Oestriol (uE3):** Decreased. * **Serum beta-hCG:** Increased. *(Note: If Inhibin-A is added to these three, it becomes the **Quadruple Screen**, which is the preferred second-trimester screening method due to higher sensitivity.)* #### High-Yield Clinical Pearls for NEET-PG * **Down Syndrome Pattern:** "HI" is high (hCG and Inhibin-A are **High**), while AFP and uE3 are **Low**. * **Edwards Syndrome (Trisomy 18):** All markers (AFP, hCG, uE3) are **decreased**. * **Timing:** The best time for the Triple/Quadruple screen is **15–20 weeks**. * **Combined Test:** Performed in the **first trimester** (11–13+6 weeks), consisting of Nuchal Translucency (NT) scan, PAPP-A (low in Down's), and beta-hCG (high in Down's).

Q: An 18-year-old G2P1L1 with a last menstrual period of May 7 presents for her first OB visit at 10 weeks. The patient had a previous pregnancy complicated by gestational diabetes and delivered a 4.2kg baby boy via cesarean section after a long labor. Which of the following should NOT be performed at each routine prenatal visit?

Real-time ultrasound for estimated fetal weight. **Explanation:** The goal of routine prenatal care is to monitor the health of the mother and fetus while identifying high-risk conditions early. However, the frequency and type of interventions must be evidence-based to avoid unnecessary costs and interventions. **Why Option B is Correct:** **Real-time ultrasound for estimated fetal weight (EFW)** is **not** indicated at every routine visit. In a low-risk pregnancy, a screening ultrasound is typically performed at 18–22 weeks (Anomaly Scan). Serial ultrasounds for growth are reserved for specific indications such as suspected Fetal Growth Restriction (FGR), macrosomia, or maternal complications (e.g., poorly controlled diabetes). Even in this patient, who has a history of a macrosomic baby (4.2kg) and gestational diabetes, growth is monitored via symphysis-fundal height (SFH) measurements starting at 20 weeks; ultrasound is used only if there is a clinical discrepancy. **Why Incorrect Options are Wrong:** * **Maternal Blood Pressure (C):** This is mandatory at every visit to screen for Preeclampsia and Gestational Hypertension. * **Urinalysis (D):** Performed at every visit (via dipstick) to screen for asymptomatic bacteriuria, proteinuria (preeclampsia), and glucosuria. * **Fetal Heart Tones (A):** Auscultation via Doppler (usually from 10–12 weeks onwards) is a standard component of every visit to confirm fetal viability and reassure the parents. **Clinical Pearls for NEET-PG:** * **Naegele’s Rule:** For this patient (LMP May 7), the EDD would be Feb 14. * **GDM Screening:** Because this patient has a history of GDM and a macrosomic baby, she should undergo an early OGT/GCT at the first visit rather than waiting until 24–28 weeks. * **Weight Gain:** Routine weighing at every visit is also a standard component of prenatal care.

Q: Acetylcholine esterase levels are highly specific for which of the following congenital anomalies?

Open spina bifida. The correct answer is **Open spina bifida**. **1. Why Open Spina Bifida is correct:** In cases of **Open Neural Tube Defects (NTDs)**, such as myelomeningocele, the neural tissue is directly exposed to the amniotic fluid [1]. Acetylcholinesterase (AChE) is an enzyme found in high concentrations within the fetal cerebrospinal fluid and neural tissues. When the neural tube fails to close, this enzyme leaks into the amniotic cavity [2]. While Alpha-fetoprotein (AFP) is a common screening marker, it can be elevated in various conditions; however, the presence of **AChE in amniotic fluid** (detected via electrophoresis) is **highly specific** for open NTDs, as it confirms the leakage of neural components [3]. **2. Why the other options are incorrect:** * **Omphalocele and Gastroschisis:** These are ventral body wall defects. While they lead to significantly elevated levels of maternal serum and amniotic fluid **AFP** (due to exposed fetal membranes or bowel), they do not typically involve neural tissue leakage, so AChE levels remain normal. * **Sacrococcygeal Teratoma:** This is a germ cell tumor. While it may occasionally cause elevated AFP if it contains yolk sac elements, it is not a neural tube defect and does not characteristically elevate AChE. **3. Clinical Pearls for NEET-PG:** * **Screening Sequence:** Maternal Serum AFP (MSAFP) is the initial screening test [2]. If elevated, ultrasound is performed. If ultrasound is inconclusive, **Amniocentesis** for AChE is the confirmatory "gold standard" for specificity. * **Closed NTDs:** Conditions like *Spina Bifida Occulta* will **not** show elevated AFP or AChE because the defect is covered by skin. * **Prevention:** Periconceptional supplementation of **Folic Acid (400 mcg/day)** reduces the risk of NTDs by 70%. For women with a previous affected pregnancy, the dose is increased to **4 mg/day**.

Q: Gestational sac is seen on transvaginal sonography as early as:

35 days from LMP. **Explanation:** The visualization of pregnancy on ultrasound follows a predictable chronological sequence based on the **Last Menstrual Period (LMP)**. 1. **Why Option C is Correct:** The **Gestational Sac (GS)** is the first definitive sign of pregnancy seen on ultrasound. On **Transvaginal Sonography (TVS)**, it typically becomes visible at **4.5 to 5 weeks (32–35 days)** of gestation. At this stage, it appears as a small, eccentric fluid collection within the endometrium (the "intradecidual sign"). By 35 days, the mean sac diameter is approximately 2–5 mm. 2. **Why Other Options are Incorrect:** * **Options A & B (18 and 21 days):** These represent the 3rd week of gestation. At this point, implantation has only just occurred or is occurring. The blastocyst is microscopic and cannot be resolved by current ultrasound technology. * **Option D (42 days):** This corresponds to 6 weeks. While the GS is easily seen here, it is no longer the "earliest" finding. By 42 days, one should expect to see the **Yolk Sac** (appears at 5.5 weeks) and often the **Fetal Pole with cardiac activity** (appears by 6 weeks). **High-Yield NEET-PG Pearls:** * **TVS vs. TAS:** TVS can detect pregnancy landmarks approximately **1 week earlier** than Transabdominal Sonography (TAS). * **Discriminatory Zone:** This is the level of serum β-hCG at which a gestational sac should be visible. For TVS, it is generally **1,500–2,000 mIU/mL**. * **Order of Appearance (TVS):** 1. Gestational Sac (4.5–5 weeks) 2. Yolk Sac (5.5 weeks) – *First reliable sign of intrauterine pregnancy.* 3. Embryo/Cardiac activity (6 weeks). * **Double Decidual Sign:** Helps distinguish a true gestational sac from a pseudogestational sac (seen in ectopic pregnancy).

Question 1

Maternal serum Alpha-fetoprotein is raised in all the following conditions EXCEPT?

Accepted Answer

Down's syndrome

Answer

Spina bifida

Answer

Multiple pregnancy

Answer

Omphalocele

Question 2

Normally, what is the upper limit for Nuchal Translucency measurement?

Accepted Answer

Less than 3 mm

Answer

More than 10 mm

Answer

Less than 6 mm

Answer

More than 5 mm

Question 3

Fetal cardiac activity is detected with transvaginal ultrasound as early as which gestational age?

Accepted Answer

6 weeks

Answer

8 weeks

Answer

10 weeks

Answer

12 weeks

Question 4

Which of the following is associated with an increased risk of thromboembolism in a normal pregnancy?

Accepted Answer

Increased production of clotting factors by the liver

Answer

Increased progesterone level

Answer

Change in blood viscosity

Answer

Decreased antithrombin III

Question 5

Prophylactic anti-D immunoglobulin is given to Rh-negative pregnant women antenatally at which gestational age?

Accepted Answer

28 weeks

Answer

20 weeks

Answer

24 weeks

Answer

32 weeks

Question 6

A hypertensive woman is seeking preconception counseling. Which of the following antihypertensive medications is advised to be continued once she becomes pregnant?

Accepted Answer

Nifedipine

Answer

Enalapril

Answer

Chlorthalidone

Answer

Losartan

Question 7

In triple screening test for Down's syndrome during pregnancy, which of the following is NOT included?

Accepted Answer

Acetyl cholinesterase

Answer

Serum beta hCG

Answer

Serum oestriol

Answer

Maternal serum Alfa fetoprotein

Question 8

An 18-year-old G2P1L1 with a last menstrual period of May 7 presents for her first OB visit at 10 weeks. The patient had a previous pregnancy complicated by gestational diabetes and delivered a 4.2kg baby boy via cesarean section after a long labor. Which of the following should NOT be performed at each routine prenatal visit?

Accepted Answer

Real-time ultrasound for estimated fetal weight

Answer

Fetal heart tones by Doppler equipment

Answer

Maternal blood pressure

Answer

Urinalysis

Question 9

Acetylcholine esterase levels are highly specific for which of the following congenital anomalies?

Accepted Answer

Open spina bifida

Answer

Omphalocele

Answer

Gastroschisis

Answer

Sacrococcygeal teratoma

Question 10

Gestational sac is seen on transvaginal sonography as early as:

Accepted Answer

35 days from LMP

Answer

18 days from LMP

Answer

21 days from LMP

Answer

42 days from LMP

Prenatal Care — MCQs

Prenatal Care — MCQs

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