Prenatal Care Practice Questions

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.

Q: What is the earliest ultrasound sign of pregnancy in a transabdominal ultrasound scan?

Fundal endometrial thickening. **Explanation:** The earliest sonographic sign of pregnancy, particularly on a transabdominal scan (TAS), is **fundal endometrial thickening**. This occurs due to the decidual reaction—the hypertrophy and increased vascularity of the endometrial lining in preparation for implantation. This "decidual sign" appears as a thickened, echogenic endometrium before a distinct gestational sac can be visualized. **Analysis of Options:** * **A. Visible gestational sac:** While the gestational sac is the first *definitive* sign of an intrauterine pregnancy, it typically appears around 5 weeks of gestation on TAS (4.5 weeks on TVS). Endometrial thickening precedes this. * **B. Apparent embryonic structures:** The fetal pole (embryo) only becomes visible within the gestational sac at approximately 6 weeks of gestation. * **C. Fundal endometrial thickening (Correct):** This is the earliest non-specific sign, appearing in the late luteal phase/early pregnancy (approx. 3-4 weeks). * **D. Identifiable cardiac movements:** This is the first sign of a *viable* pregnancy, usually detected when the embryo reaches a crown-rump length (CRL) of 5mm (around 6-6.5 weeks). **High-Yield Clinical Pearls for NEET-PG:** * **Double Decidual Sign:** Two concentric echogenic rings surrounding the gestational sac; it helps differentiate a true gestational sac from a "pseudogestational sac" seen in ectopic pregnancy. * **Discriminatory Zone:** The serum β-hCG level at which a gestational sac should be visible (1500–2000 mIU/ml for TVS; 6500 mIU/ml for TAS). * **Mean Sac Diameter (MSD):** A gestational sac should be visible via TVS when the MSD is 2–3 mm.

Q: The triple test for the diagnosis of Down syndrome includes all of the following except?

Inhibin A. The **Triple Test** is a maternal serum screening performed between **15 and 20 weeks** of gestation (ideally 16–18 weeks) to screen for chromosomal abnormalities like Down syndrome (Trisomy 21) and neural tube defects. ### Why Inhibin A is the Correct Answer Inhibin A is **not** a component of the Triple Test. It is the fourth marker added to the Triple Test to create the **Quadruple (Quad) Test**. The addition of Inhibin A increases the sensitivity for detecting Down syndrome from approximately 65-70% (Triple Test) to 80-85% (Quad Test). ### Explanation of Incorrect Options (Components of Triple Test) In Down syndrome, the typical "Triple Test" profile shows: * **A. Beta-hCG:** Levels are characteristically **increased**. * **B. Alpha-fetoprotein (AFP):** Levels are characteristically **decreased**. (Note: AFP is increased in open neural tube defects). * **D. Serum Unconjugated Estriol (uE3):** Levels are characteristically **decreased**. ### High-Yield Clinical Pearls for NEET-PG * **Quadruple Test:** Includes AFP, uE3, hCG, and **Inhibin A** (Inhibin A is **increased** in Down syndrome). * **Mnemonic for Down Syndrome (Quad Test):** "HI" is High – **H**CG and **I**nhibin A are elevated; the others (AFP, uE3) are low. * **Edwards Syndrome (Trisomy 18):** All markers (AFP, uE3, and hCG) are typically **decreased**. * **Combined Test (First Trimester):** Performed at 11–13 weeks; includes PAPP-A (decreased), Beta-hCG (increased), and Nuchal Translucency (increased) on ultrasound. * **Best Screening Tool:** Cell-free DNA (cfDNA) / NIPT has the highest sensitivity (>99%) but is more expensive.

Q: At what gestational age can the earliest fetal heart activity be detected?

6.0-6.5 weeks. **Explanation:** The detection of fetal heart activity is a critical milestone in early pregnancy, serving as the definitive sign of a viable intrauterine pregnancy. **Why Option A is Correct:** The fetal heart is the first functional organ to develop. Spontaneous rhythmic contractions begin around the 22nd day of development (approximately 5 weeks of gestation). However, these are not consistently visible on imaging immediately. Using **Transvaginal Sonography (TVS)**, fetal heart activity can typically be detected when the Crown-Rump Length (CRL) reaches 1–2 mm, which corresponds to a gestational age of **6.0 to 6.5 weeks**. At this stage, the heart rate is relatively slow (approx. 100-110 bpm) before increasing. **Analysis of Incorrect Options:** * **Options B & C (6.5–7.5 weeks):** While heart activity is clearly visible during this window, it is not the *earliest* point of detection. By 7 weeks, the heart rate typically peaks around 175 bpm. * **Option D (8 weeks):** This is the timeframe when fetal heart activity can usually be detected via **Transabdominal Sonography (TAS)**. TAS has lower resolution than TVS and requires a larger embryo and more advanced gestation for accurate detection. **NEET-PG High-Yield Pearls:** * **TVS vs. TAS:** TVS can detect pregnancy milestones about 1 week earlier than TAS. * **Discriminatory Zone:** Fetal heart activity should always be visible by TVS when the CRL is **>7 mm**. If absent at this size, it suggests pregnancy failure (Missed Abortion). * **Mean Sac Diameter (MSD):** A yolk sac should be visible when the MSD is 20 mm (TVS); an embryo with a heartbeat should be visible when the MSD is **>25 mm**. * **Doppler:** While M-mode is used to document the rate, pulse-wave Doppler is generally avoided in the first trimester to prevent thermal bioeffects on the developing embryo.

Q: An obstetrician sees a pregnant patient who was exposed to rubella virus in the eighteenth week of pregnancy. She does not remember getting a rubella vaccination. What is the best immediate course of action?

Order a rubella antibody titer to determine immune status. The management of rubella exposure in pregnancy depends on the mother’s immune status and the gestational age at exposure. **Explanation of the Correct Answer:** The immediate priority is to determine if the mother is already immune. Many adults have immunity through childhood vaccination or prior subclinical infection. A **Rubella IgG antibody titer** should be ordered: * **If IgG is positive:** The patient is immune, and there is no risk of Congenital Rubella Syndrome (CRS). * **If IgG is negative:** The patient is susceptible. A second sample should be taken 2–3 weeks later to check for seroconversion (IgM/IgG), which would indicate an acute infection. **Analysis of Incorrect Options:** * **Option A:** Termination is not indicated without confirming maternal infection and assessing fetal risk. Furthermore, the risk of CRS decreases significantly after the first trimester. * **Option C:** This is factually incorrect. Rubella is most dangerous in the **first trimester** (up to 80% risk of CRS). While the risk drops after 16–18 weeks, exposure in the eighteenth week still requires investigation. * **Option D:** Rubella immune globulin does not reliably prevent fetal infection and is only considered if a susceptible woman refuses termination after a confirmed exposure. **NEET-PG High-Yield Pearls:** * **Maximum Risk:** The highest risk for CRS is during the first 12 weeks of gestation. * **Classic Triad of CRS:** Sensorineural deafness (most common), Cataracts (salt-and-pepper retinopathy), and Cardiac defects (Patent Ductus Arteriosus). * **Vaccination:** The Rubella vaccine (RA 27/3 strain) is a **live-attenuated vaccine** and is **contraindicated during pregnancy**. Women should avoid pregnancy for 1 month (28 days) after receiving the MMR vaccine. * **Postpartum:** If a pregnant woman is found to be non-immune, she should be vaccinated in the immediate postpartum period.

Q: At which gestational age is external cephalic version typically performed?

36 weeks. **Explanation:** External Cephalic Version (ECV) is a procedure where the fetus is manually rotated from a breech or transverse lie to a cephalic presentation through the maternal abdomen. **Why 36 weeks is correct:** The timing of ECV is a balance between the likelihood of spontaneous version and the risks of prematurity. * **In Nulliparous women:** ECV is typically performed at **36 weeks**. * **In Multiparous women:** It is often delayed until **37 weeks**. At 36 weeks, the fetus is large enough that spontaneous version is unlikely, yet there is still sufficient amniotic fluid and space to facilitate the maneuver. Most importantly, if a complication occurs (e.g., placental abruption or cord prolapse) necessitating emergency delivery, the fetus has reached near-term maturity. **Why other options are incorrect:** * **34 weeks:** Too early. Many fetuses (approx. 25%) will undergo spontaneous version to cephalic before 36 weeks. Performing it now increases the risk of the fetus reverting to breech and exposes a preterm infant to unnecessary delivery risks if complications arise. * **38/40 weeks:** Too late. As the pregnancy advances, the fetus grows larger and the relative volume of amniotic fluid decreases, significantly reducing the success rate of the procedure. **High-Yield Clinical Pearls for NEET-PG:** * **Prerequisites:** Reactive NST (reassuring fetal heart rate), adequate liquor, and no contraindications to vaginal delivery. * **Success Rate:** Approximately 50–60%. * **Tocolysis:** Use of beta-mimetics (e.g., Terbutaline) increases success rates by relaxing the uterus. * **Absolute Contraindications:** Placenta previa, multifetal gestation, ruptured membranes, and prior classical cesarean section. * **Rh Status:** Rh-negative non-sensitized mothers must receive **Anti-D immunoglobulin** after the procedure to prevent isoimmunization.

Q: In Down syndrome, which of the following markers is NOT typically measured in the second-trimester quadruple screening test performed between 14-20 weeks of gestation?

Progesterone. The **Quadruple Screening Test** (Quad Screen) is a prenatal screening tool performed between **15 and 20 weeks** (ideally 16–18 weeks) of gestation to assess the risk of chromosomal abnormalities like Down syndrome (Trisomy 21) and Trisomy 18, as well as neural tube defects. ### Why Progesterone is the Correct Answer: **Progesterone** is not a component of the Quad screen. While it is essential for maintaining pregnancy, its levels do not serve as a reliable predictive marker for fetal aneuploidy. The fourth marker added to the "Triple Screen" to create the "Quad Screen" is **Inhibin A**, which significantly increases the sensitivity for detecting Down syndrome. ### Explanation of Incorrect Options (The Quad Markers): In a pregnancy affected by **Down syndrome**, the markers typically show the following patterns: * **Alpha-fetoprotein (AFP):** Levels are **decreased**. (Low AFP is also seen in Trisomy 18). * **Human chorionic gonadotropin (hCG):** Levels are **increased**. * **Inhibin A:** Levels are **increased**. * **Unconjugated Estriol (uE3):** (Not listed in options but the 4th marker) Levels are **decreased**. ### High-Yield Clinical Pearls for NEET-PG: * **Mnemonic for Down Syndrome (HI):** **H**CG and **I**nhibin A are **HI**gh; the others (AFP and uE3) are low. * **Trisomy 18 (Edwards Syndrome):** All markers (AFP, hCG, uE3) are typically **decreased**. * **Neural Tube Defects (NTD):** Characterized by **elevated AFP** levels. * **First Trimester Screening (11–13.6 weeks):** Uses PAPP-A (decreased), β-hCG (increased), and Nuchal Translucency (increased) for Down syndrome. * **Confirmatory Test:** Screening tests are not diagnostic. If the Quad screen is positive, definitive diagnosis requires **Amniocentesis** or **CVS**.

Question 1

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 2

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 3

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

Question 4

Which of the following is unrelated to fetal souffle?

Accepted Answer

It is due to the rush of blood through the umbilical arteries.

Answer

It is a soft blowing murmur synchronous with the fetal heart sounds.

Answer

It is heard in approximately 15% of cases.

Answer

Its presence is diagnostic of pregnancy.

Question 5

What is the earliest ultrasound sign of pregnancy in a transabdominal ultrasound scan?

Accepted Answer

Fundal endometrial thickening

Answer

Visible gestational sac

Answer

Apparent embryonic structures

Answer

Identifiable cardiac movements

Question 6

The triple test for the diagnosis of Down syndrome includes all of the following except?

Accepted Answer

Inhibin A

Answer

Beta hCG

Answer

Alpha-fetoprotein

Answer

Serum estriol level

Question 7

At what gestational age can the earliest fetal heart activity be detected?

Accepted Answer

6.0-6.5 weeks

Answer

6.5-7 weeks

Answer

7.1-7.5 weeks

Answer

8 weeks

Question 8

An obstetrician sees a pregnant patient who was exposed to rubella virus in the eighteenth week of pregnancy. She does not remember getting a rubella vaccination. What is the best immediate course of action?

Accepted Answer

Order a rubella antibody titer to determine immune status

Answer

Terminate the pregnancy

Answer

Reassure the patient because rubella is not a problem until after the thirtieth week

Answer

Administer rubella immune globulin

Question 9

At which gestational age is external cephalic version typically performed?

Accepted Answer

36 weeks

Answer

34 weeks

Answer

38 weeks

Answer

40 weeks

Question 10

In Down syndrome, which of the following markers is NOT typically measured in the second-trimester quadruple screening test performed between 14-20 weeks of gestation?

Accepted Answer

Progesterone

Answer

Alpha-fetoprotein

Answer

Human chorionic gonadotropin (hCG)

Answer

Inhibin A

Prenatal Care — MCQs

Prenatal Care — MCQs

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