A pregnant woman at term presents with a symphysiofundal height of 40 cm. What is the most likely approximate fetal weight?
What is the primary hormonal cause of hot flushes experienced during menopause?
What is the recommended dose of folic acid for a patient with a history of neural tube defect (NTD) in a previous pregnancy?
A G2P1L1 female presents at 28 weeks of gestation with a 1:4 anti-D titre. What is the most appropriate management option?
Number of stem villi at term in human placenta is?
The window of implantation occurs at which of the following time periods after fertilization?
All are true about uteroplacental circulation except:
Which serum level is increased in premature ovarian failure?
Which of the following is not considered a marker of ovarian reserve?
Which of the following is a side effect of Progestin Only Pills (POPs)?
NEET-PG 2015 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 31: A pregnant woman at term presents with a symphysiofundal height of 40 cm. What is the most likely approximate fetal weight?
- A. 3 kg
- B. 4 kg (Correct Answer)
- C. 3.3 kg
- D. 4.3 kg
Explanation: ***4 kg*** - Using **Johnson's formula** for fetal weight estimation: Weight (g) = (SFH in cm - n) × 155, where n = 12 if fetal vertex is above ischial spines or n = 11 if at/below spines - For SFH of **40 cm**: (40 - 12) × 155 = **4,340 g ≈ 4 kg** or (40 - 11) × 155 = 4,495 g ≈ 4.5 kg - An approximate weight of **4 kg** is the most reasonable estimate for an SFH of 40 cm at term - This represents a larger than average fetus, which is consistent with the clinical measurement *3 kg* - While 3 kg is a common average birth weight, Johnson's formula calculation for an SFH of **40 cm** yields a significantly higher estimate - A weight of 3 kg would typically correlate with an SFH of approximately **32-33 cm**, not 40 cm - This option significantly underestimates the fetal weight for the given measurement *3.3 kg* - Although closer to average birth weight, this still **underestimates** the fetal weight suggested by an SFH of 40 cm - Using Johnson's formula, this measurement would correlate with an SFH of approximately **34-35 cm**, not 40 cm - The 40 cm measurement indicates a larger fetus than this estimate suggests *4.3 kg* - This represents the more **precise calculation** using Johnson's formula: (40 - 12) × 155 = 4,340 g - While mathematically accurate, **4 kg is the more commonly used approximation** in clinical practice for ease of communication - Both 4 kg and 4.3 kg are acceptable estimates, but 4 kg is the standard teaching answer for NEET-PG
Question 32: What is the primary hormonal cause of hot flushes experienced during menopause?
- A. Increased noradrenaline with normal estrogen levels
- B. Increased noradrenaline
- C. Decreased estrogen levels (Correct Answer)
- D. Both increased noradrenaline and decreased estrogen levels
Explanation: ***Decreased estrogen levels*** - **Decreased estrogen** is the primary hormonal change during menopause, leading to thermoregulatory dysfunction in the hypothalamus. - This hormonal imbalance causes the **vasomotor symptoms** like hot flushes and night sweats. *Increased noradrenaline* - While **noradrenaline** (norepinephrine) is involved in thermoregulation, its increase is a **secondary event** triggered by the initial estrogen deficiency, not the primary cause. - Increased noradrenaline can exacerbate the **vasodilation** and heat dissipation experienced during a hot flush. *Increased noradrenaline with normal estrogen levels* - This option is incorrect because hot flushes are characteristic of menopause, which is defined by **decreased estrogen levels**. - **Normal estrogen levels** would typically prevent the severe thermoregulatory instability that causes hot flushes. *Both increased noradrenaline and decreased estrogen levels* - Although both factors are involved, the question asks for the **primary hormonal cause**. **Decreased estrogen** initiates the cascade of events, including the subsequent alteration of neurotransmitter levels like noradrenaline. - Noradrenaline's role is more of a **mediator** in the physiological response to the primary estrogen deficiency.
Question 33: What is the recommended dose of folic acid for a patient with a history of neural tube defect (NTD) in a previous pregnancy?
- A. 0.5 mg
- B. 1 mg
- C. 2 mg
- D. 4 mg (Correct Answer)
Explanation: ***4 mg*** - For women with a prior history of a **neural tube defect (NTD)-affected pregnancy**, a higher dose of **4 mg of folic acid daily** is recommended to significantly reduce the risk of recurrence. - This increased dosage is crucial for achieving adequate maternal folate levels to prevent NTDs, starting at least one month before conception and continuing through the first trimester. *0.5 mg* - This dose is lower than the standard recommendation for women without a history of NTDs and is insufficient for high-risk individuals. - Suboptimal folic acid levels can still lead to a higher risk of NTD recurrence in patients with a history of NTD-affected pregnancies. *1 mg* - While 1 mg is higher than the general recommendation, it is still insufficient for women with a **history of NTD in a previous pregnancy**. - Current guidelines suggest a significantly higher dose for secondary prevention due to altered folate metabolism or higher requirements in these individuals. *2 mg* - This dose is also lower than the **established recommendation for high-risk women** who have had a previous NTD-affected pregnancy. - It does not provide the optimal level of protection required to reduce the risk of recurrence effectively.
Question 34: A G2P1L1 female presents at 28 weeks of gestation with a 1:4 anti-D titre. What is the most appropriate management option?
- A. MCA Doppler (Correct Answer)
- B. Caesarean section
- C. Induction of labour
- D. Amniocentesis
Explanation: ***MCA Doppler*** - The presence of anti-D antibodies in a pregnant woman indicates **Rh isoimmunization**, which can lead to **hemolytic disease of the fetus and newborn (HDFN)**. - Even though a titre of **1:4 is below the critical threshold** (usually 1:16 or 1:32), any detectable anti-D titre at 28 weeks warrants **fetal surveillance** to detect early signs of fetal anemia. - **Middle cerebral artery (MCA) Doppler** is the **non-invasive gold standard** for detecting fetal anemia by measuring peak systolic velocity (PSV), which increases in anemic fetuses due to hyperdynamic circulation. - Serial MCA Doppler monitoring allows timely intervention if fetal anemia develops, avoiding unnecessary invasive procedures. *Caesarean section* - This is a mode of delivery and would only be considered if there were severe **fetal compromise** or other obstetric indications after proper monitoring and management. - At 28 weeks gestation with a low anti-D titre, immediate delivery is **not indicated** and would result in significant prematurity risks. *Induction of labour* - Induction of labour is a delivery method that would only be planned at term or for specific indications like severe fetal compromise unresponsive to other interventions. - At **28 weeks gestation**, the focus should be on **monitoring and prolonging pregnancy** while ensuring fetal wellbeing, not on delivery. *Amniocentesis* - Historically used to assess **bilirubin levels (ΔOD450)** in amniotic fluid as an indirect measure of fetal hemolysis, but it is an **invasive procedure** with risks (miscarriage ~1%, infection, worsening sensitization). - **MCA Doppler has largely replaced amniocentesis** for initial and serial assessment of fetal anemia due to its non-invasive nature, high sensitivity, and ability to be repeated safely.
Question 35: Number of stem villi at term in human placenta is?
- A. 60
- B. 240 (Correct Answer)
- C. 120
- D. 480
Explanation: ***240*** - At term, the **human placenta** contains numerous **stem villi** which branch extensively to form the villous tree. - The approximate number of **stem villi** at term is around **240**, contributing to the large surface area for maternal-fetal exchange. *60* - This number is significantly **lower** than the actual count of **stem villi** found in a mature, term placenta. - Such a low number would result in an **insufficient surface area** for effective nutrient and gas exchange. *120* - While higher than 60, this number is still **underestimated** for the quantity of **stem villi** present in a full-term human placenta. - A placenta with only 120 stem villi might not be able to adequately support a fetus at term. *480* - This number is an **overestimation** of the typical count of **stem villi** in a human placenta at term. - While villi are extensive, 480 stem villi represent a significantly higher number than usually observed.
Question 36: The window of implantation occurs at which of the following time periods after fertilization?
- A. 6-10 days (Correct Answer)
- B. 12 days
- C. 12 weeks
- D. 6 weeks
Explanation: ***6-10 days*** - The uterus is most receptive to implantation during the **"window of implantation,"** which occurs roughly **6 to 10 days post-fertilization**, coinciding with the mid-luteal phase. - During this period, the **endometrial lining** undergoes specific changes, guided by hormonal signals from **progesterone**, making it optimal for the blastocyst to attach. *12 days* - While implantation can still occur, the **peak receptivity window** is generally considered to be narrower, between 6 and 10 days. - By day 12, changes in the **endometrial environment** may start to reduce the likelihood of successful implantation. *12 weeks* - **12 weeks** refer to the end of the first trimester of pregnancy and is far too late for the initial implantation event. - Implantation must have occurred much earlier for a viable pregnancy at this stage. *6 weeks* - **6 weeks** refers to an established pregnancy, at which point implantation would have occurred several weeks prior. - The process of implantation is completed within the first two weeks post-fertilization.
Question 37: All are true about uteroplacental circulation except:
- A. The villi depend on the maternal blood for their nutrition
- B. Blood in the intervillous space is completely replaced 3-4 times per minute
- C. A mature placenta has 150 ml of blood in the villi system and 350 ml of blood in the intervillous space (Correct Answer)
- D. Intervillous blood flow at term is 500-600 ml per minute
Explanation: ***A mature placenta has 150 ml of blood in the villi system and 350 ml of blood in the intervillous space*** - This statement is incorrect because a **mature placenta** typically holds approximately **350 ml of blood** in the **villi system** and **150 ml of blood** in the **intervillous space**, which is the reverse of what is stated. - The villi system contains the fetal blood, which has a larger volume within the placental unit. *Blood in the intervillous space is completely replaced 3-4 times per minute* - This is a correct statement regarding uteroplacental circulation, as the **high turnover rate** ensures efficient **nutrient and gas exchange** between mother and fetus. - The rapid replacement prevents stagnant blood and facilitates continuous delivery of essential substances. *The villi depend on the maternal blood for their nutrition* - This statement is true because the **chorionic villi**, which are the functional units of the placenta, are bathed in **maternal blood** within the intervillous space. - The placental tissue itself receives its **nutrients and oxygen** directly from this maternal blood supply. *Intervillous blood flow at term is 500-600 ml per minute* - This is an accurate physiological fact. At term, the **maternal blood flow** through the intervillous space is indeed substantial, typically ranging from **500 to 700 ml per minute**, ensuring adequate perfusion for the growing fetus. - This significant blood flow is crucial for meeting the high metabolic demands of the fetus.
Question 38: Which serum level is increased in premature ovarian failure?
- A. Serum Inhibin
- B. Serum FSH (Correct Answer)
- C. Serum Estradiol
- D. Serum Progesterone
Explanation: ***Serum FSH*** - In **premature ovarian failure**, the ovaries fail to produce sufficient estrogen and inhibin, leading to a loss of negative feedback on the pituitary gland. - This lack of negative feedback results in continuously **elevated levels of FSH** as the pituitary tries to stimulate the non-responsive ovaries. *Serum Inhibin* - **Inhibin** is a hormone produced by ovarian granulosa cells, which normally inhibits FSH secretion. - In premature ovarian failure, due to ovarian dysfunction, **inhibin levels are typically decreased**, not increased. *Serum Estradiol* - **Estradiol** is the primary estrogen produced by the ovaries. - In premature ovarian failure, the ovaries are failing, resulting in **decreased production of estrogen/estradiol**. *Serum Progesterone* - **Progesterone** is primarily produced after ovulation by the corpus luteum. - In premature ovarian failure, ovulation is impaired or absent, leading to **low or undetectable progesterone levels**.
Question 39: Which of the following is not considered a marker of ovarian reserve?
- A. Ovarian volume
- B. Inhibin B
- C. Anti-Müllerian Hormone (AMH)
- D. Inhibin A (Correct Answer)
Explanation: ***Inhibin A*** - **Inhibin A** levels primarily rise during the mid to late luteal phase and are involved in regulating FSH, but they are not a reliable or commonly used marker for **ovarian reserve**. - Its fluctuations are more indicative of the presence of a **corpus luteum** and short-term ovarian function rather than the total follicular pool. *Inhibin B* - **Inhibin B** is produced by granulosa cells of small antral follicles and is an important marker of **ovarian reserve**. - It inversely correlates with **FSH** levels in the early follicular phase, reflecting the number of developing follicles. *Ovarian volume* - **Ovarian volume**, particularly when measured by ultrasound, can be an indicator of **ovarian reserve**. - Smaller ovarian volume is generally associated with a reduced number of **antral follicles** and lower ovarian reserve. *Anti-Müllerian Hormone (AMH)* - **AMH** is a well-established and highly reliable marker of **ovarian reserve**, produced by the granulosa cells of preantral and small antral follicles. - Its levels correlate directly with the total number of remaining **primordial follicles** and are relatively stable throughout the menstrual cycle.
Question 40: Which of the following is a side effect of Progestin Only Pills (POPs)?
- A. Ovarian cysts (Correct Answer)
- B. Venous thromboembolism
- C. Increased risk of diabetes mellitus
- D. Ectopic pregnancy
Explanation: ***Ovarian cysts*** - **Functional ovarian cysts** are a known side effect of Progestin Only Pills (**POPs**), as POPs can alter the normal ovulatory cycle but usually do not completely suppress follicular development. - While generally benign and self-resolving, they can cause pain and discomfort. *Venous thromboembolism* - **POPs** are not significantly associated with an increased risk of **venous thromboembolism** due to the absence of estrogen, unlike combined hormonal contraceptives. - This is a key advantage of POPs, making them suitable for individuals at risk for thromboembolic events. *Increased risk of diabetes mellitus* - There is generally **no significant increased risk** of **diabetes mellitus** associated with POPs. - While some hormonal contraceptives *may* have minor effects on glucose metabolism, this is not a prominent or clinically significant side effect of POPs. *Ectopic pregnancy* - POPs **do not increase the risk of ectopic pregnancy**. In fact, they **reduce the overall pregnancy rate**, including ectopic pregnancies, by preventing ovulation. - However, if a pregnancy does occur while on POPs, there is a *slightly higher proportion* of those pregnancies that may be ectopic compared to unaided conceptions, but the *absolute risk* remains low.