Prenatal Care Practice Questions

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).

Q: Which of the following parameters are used to estimate gestational age in the last trimester?

Abdominal circumference, Biparietal diameter, Femur length. **Explanation:** In obstetric ultrasonography, the parameters used to estimate gestational age (GA) change as the pregnancy progresses. By the **third trimester**, the accuracy of ultrasound for dating decreases significantly (margin of error ± 2–3 weeks). The most reliable estimation during this period is derived from a composite of multiple biometric measurements. **Why Option D is Correct:** The standard biometric parameters used in the late second and third trimesters include: 1. **Biparietal Diameter (BPD):** Measured at the level of the thalami and cavum septum pellucidum. 2. **Head Circumference (HC):** Often used alongside BPD. 3. **Abdominal Circumference (AC):** The most sensitive parameter for assessing fetal growth and nutrition (IUGR/Macrosomia). 4. **Femur Length (FL):** The most reliable long bone measurement for GA. **Why Other Options are Incorrect:** * **Crown-Rump Length (CRL):** This is the most accurate parameter for dating a pregnancy, but **only in the first trimester** (up to 13 weeks 6 days). After this, the fetus begins to curl/flex, making CRL measurements inaccurate. Since CRL is included in Options A, B, and C, they are incorrect for the third trimester. **High-Yield Clinical Pearls for NEET-PG:** * **Best parameter for 1st Trimester:** Crown-Rump Length (CRL). Accuracy: ± 3–5 days. * **Best parameter for 2nd Trimester:** Biparietal Diameter (BPD). * **Most sensitive parameter for IUGR:** Abdominal Circumference (AC). * **Transcerebellar Diameter:** A "gestational age independent" parameter; it remains reliable even in cases of IUGR or altered head shapes (dolichocephaly/brachycephaly). * **Rule of Thumb:** The earlier the ultrasound is performed, the more accurate the gestational age estimation.

Q: Ultrasound is done in the 1st trimester for all except:

To know the position of the placenta. ### Explanation The primary goal of a first-trimester ultrasound (performed before 13 weeks 6 days) is to confirm viability, establish accurate dating, and determine chronicity in multiple gestations. **Why Option D is the Correct Answer:** In the first trimester, the placenta is not yet fully formed; instead, we see the **decidua capsularis and basalis**. More importantly, the lower uterine segment has not yet developed. As the uterus grows, the placenta appears to "move" away from the internal os—a phenomenon known as **placental migration**. Therefore, diagnosing the definitive position of the placenta (to rule out Placenta Previa) is only clinically reliable in the **second and third trimesters** (typically after 18–20 weeks). **Analysis of Incorrect Options:** * **A. Multiple pregnancy:** The first trimester is the "Gold Standard" time to determine **chorionicity** (e.g., identifying the T-sign or Lambda sign), which is crucial for managing twin pregnancies. * **B. Fetal anomalies:** While the detailed anatomy scan occurs at 18–20 weeks, major structural anomalies (like Anencephaly) and chromosomal markers (like **Nuchal Translucency**) are assessed between 11–13.6 weeks. * **C. To estimate gestational age:** The **Crown-Rump Length (CRL)** measured in the first trimester is the most accurate parameter for dating a pregnancy (error margin of ±3–5 days). **High-Yield Clinical Pearls for NEET-PG:** * **Most accurate measurement for dating:** CRL (1st Trimester). * **First sign of pregnancy on USG:** Gestational sac (at ~4.5–5 weeks). * **First sign of intrauterine pregnancy:** Yolk sac (at ~5–5.5 weeks). * **Placental Migration:** Occurs due to the differential growth of the lower uterine segment; 90% of "low-lying" placentas identified early will resolve by term.

Q: What is Osiander's sign?

Pulsation in the lateral vaginal fornix. **Explanation:** **Osiander’s sign** is a clinical sign of early pregnancy, typically appearing around the **8th week** of gestation. It is characterized by the perception of **increased pulsations in the lateral vaginal fornices** during a pelvic examination. This occurs due to the marked increase in vascularity and blood flow to the uterus (hyperemia) to support the developing fetus. **Analysis of Options:** * **Option A (Correct):** Osiander’s sign is specifically defined as the increased pulsation felt through the lateral fornices, resulting from the hypertrophy of the uterine arteries. * **Option B (Incorrect):** This describes **Chadwick’s sign** (or Jacquemier’s sign), which is a bluish discoloration of the cervix, vagina, and labia due to venous congestion. * **Option C (Incorrect):** This describes **Goodell’s sign**, which is the significant softening of the cervix (often compared to the feel of the lips rather than the nose) occurring around the 6th week. * **Option D (Incorrect):** This describes **Hegar’s sign**, where the softening of the uterine isthmus allows the fingers of the bimanual exam to nearly approximate. **High-Yield Clinical Pearls for NEET-PG:** * **Piskacek’s Sign:** Asymmetrical enlargement of the uterus if implantation occurs near one of the cornua. * **Palmer’s Sign:** Rhythmic uterine contractions felt during a bimanual examination (early pregnancy). * **Timeline:** Most of these "probable" signs of pregnancy (Hegar, Goodell, Chadwick, Osiander) appear between **6 to 10 weeks** of gestation. * **Vascularity:** Remember that Osiander’s sign is a direct result of the **uterine artery** supplying more blood to the gravid uterus.

Question 1

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 2

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 3

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 4

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 5

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 6

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 7

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

Question 8

Which of the following parameters are used to estimate gestational age in the last trimester?

Accepted Answer

Abdominal circumference, Biparietal diameter, Femur length

Answer

Cranial Rump length, Abdominal circumference, Biparietal diameter

Answer

Cranial Rump length, Biparietal diameter, Femur length

Answer

Cranial Rump length, Biparietal diameter

Question 9

Ultrasound is done in the 1st trimester for all except:

Accepted Answer

To know the position of the placenta

Answer

Multiple pregnancy

Answer

Fetal anomalies

Answer

To estimate gestational age

Question 10

What is Osiander's sign?

Accepted Answer

Pulsation in the lateral vaginal fornix

Answer

Bluish colour change in the vagina

Answer

Softening of the cervix

Answer

On bimanual palpation the fingers can be approximated as if nothing is in between

Prenatal Care — MCQs

Prenatal Care — MCQs

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