Hydrocephalus is best detected antenatally by :
Which of the following is not considered a marker of ovarian reserve?
Most common antigen involved in erythroblastosis fetalis is:
A G2P1L1 female presents at 28 weeks of gestation with a 1:4 anti-D titre. What is the most appropriate management option?
All are true about uteroplacental circulation except:
The window of implantation occurs at which of the following time periods after fertilization?
Number of stem villi at term in human placenta is?
Which serum level is increased in premature ovarian failure?
Which of the following precancerous conditions, if treated, has the highest likelihood of not leading to cancer?
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 11: Hydrocephalus is best detected antenatally by :
- A. X-ray abdomen
- B. Amniocentesis
- C. Clinical examination
- D. Ultrasonography (Correct Answer)
Explanation: ***Ultrasonography*** - **Antenatal ultrasonography** is the primary and most effective method for detecting fetal hydrocephalus. - It allows direct visualization of **ventricular dilation**, the key diagnostic finding in hydrocephalus (lateral ventricles >10mm at atrium level). - USG is **safe, non-invasive**, and can be performed repeatedly without radiation exposure. - It also helps identify associated anomalies and determine the cause of hydrocephalus. *X-ray abdomen* - **X-rays** expose the fetus to **ionizing radiation**, posing risks and violating ALARA (As Low As Reasonably Achievable) principles. - They provide limited detail of **soft tissue structures** like brain ventricles, making them unsuitable for diagnosing hydrocephalus. - X-rays are not used for antenatal diagnosis of fetal brain abnormalities. *Amniocentesis* - **Amniocentesis** is primarily used for **chromosomal analysis** and genetic testing, not for direct visualization of brain anomalies. - While some genetic conditions can lead to hydrocephalus, amniocentesis doesn't directly detect the hydrocephalus itself. - It cannot visualize structural fetal abnormalities. *Clinical examination* - **Antenatal clinical examination** of the mother cannot directly assess fetal brain abnormalities. - It may suggest fetal issues if there is an abnormally large uterine size or polyhydramnios, but it **lacks the specificity and sensitivity** to diagnose hydrocephalus. - Clinical examination alone is inadequate for detecting structural fetal anomalies.
Question 12: 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 13: Most common antigen involved in erythroblastosis fetalis is:
- A. C antigen in Rh group
- B. E antigen in Rh group
- C. Duffy antigen
- D. D antigen in Rh group (Correct Answer)
Explanation: ***D antigen in Rh group*** - The **D antigen** is the most immunogenic of the Rh antigens and is responsible for the vast majority of cases of **erythroblastosis fetalis** (hemolytic disease of the fetus and newborn). - When an **Rh-negative mother** is exposed to Rh-positive fetal blood (usually during previous pregnancies or transfusions), she can form antibodies against the D antigen, which can then cross the placenta in subsequent pregnancies and attack Rh-positive fetal red blood cells. *C antigen in Rh group* - While the **C antigen** is part of the Rh blood group system, antibodies to it are much less common and typically cause less severe hemolytic disease compared to anti-D antibodies. - The C antigen is less immunogenic than the D antigen, meaning it is less likely to provoke an immune response in an Rh-negative individual. *E antigen in Rh group* - Similar to the C antigen, the **E antigen** is another Rh antigen, but antibodies against it (anti-E) are also less frequently implicated in severe erythroblastosis fetalis than anti-D. - Antibodies to E can cause hemolytic disease, but their clinical significance is usually milder than that of anti-D. *Duffy antigen* - The **Duffy antigen system** is separate from the Rh system and is known for its role in resistance to certain malarial parasites (e.g., *Plasmodium vivax*). - Although antibodies to Duffy antigens (anti-Fya, anti-Fyb) can cause **hemolytic disease of the fetus/newborn**, they are a far less common cause of erythroblastosis fetalis than antibodies to the Rh D antigen.
Question 14: 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 15: 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 16: 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 17: 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 18: 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 19: Which of the following precancerous conditions, if treated, has the highest likelihood of not leading to cancer?
- A. Cervical intraepithelial Neoplasia (Correct Answer)
- B. Ductal carcinoma in situ of breast
- C. Lobular carcinoma in situ of breast
- D. Vaginal intraepithelial neoplasia
Explanation: ***Cervical intraepithelial neoplasia (CIN)*** - CIN has a high success rate with treatment (e.g., **cryotherapy**, **LEEP**), often completely eradicating the dysplastic cells and preventing progression to **invasive cervical cancer**. - The effectiveness of screening via **Pap smears** allows for early detection and intervention, significantly reducing cancer risk. *Ductal carcinoma in situ (DCIS) of breast* - While treatable, DCIS carries a higher risk of recurrence and progression to **invasive breast cancer** in the same or contralateral breast compared to CIN. - Treatment often involves **lumpectomy** with or without radiation, and sometimes **total mastectomy**, reflecting its more serious potential. *Lobular carcinoma in situ (LCIS) of breast* - LCIS is largely considered a **risk indicator** for future invasive cancer in either breast, rather than a direct precursor that inevitably progresses. - Management often involves **close surveillance** or **chemoprevention**, as surgical excision does not prevent cancer development in other areas of the breast. *Vaginal intraepithelial neoplasia (VAIN)* - While treatable, VAIN is less common and often coexists with or follows **cervical or vulvar neoplasia**, indicating a broader field defect due to **HPV**. - Recurrence rates post-treatment can be significant, and patients often require long-term follow-up due to the continued risk of progression.
Question 20: 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.