In which part of the fallopian tube is ectopic pregnancy most likely to survive longer?
Most common antigen involved in erythroblastosis fetalis is:
Hydrocephalus is best detected antenatally by :
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?
Which of the following describes the points marked in the diagram of pelvic measurements?
Which of the following is not considered an absolute contraindication for the use of an Intra Uterine Contraceptive Device (IUD)?
NEET-PG 2015 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 61: In which part of the fallopian tube is ectopic pregnancy most likely to survive longer?
- A. Isthmus
- B. Ampulla
- C. Cornua
- D. Interstitial (Correct Answer)
Explanation: ***Interstitial*** - An **interstitial (intramural) pregnancy** occurs in the portion of the fallopian tube that passes through the muscular wall of the uterus, known as the **cornua**. This position allows for a larger and more distensible space, potentially accommodating the pregnancy for a longer duration before rupture. - The surrounding **myometrial tissue** can provide a temporary blood supply and structural support, leading to later presentation (often up to 12-16 weeks) and often more significant hemorrhage upon rupture due to the rich vascularization of the uterine wall. - Interstitial pregnancies account for approximately 2-4% of all ectopic pregnancies but have a higher mortality rate due to massive hemorrhage when rupture occurs. *Isthmus* - The **isthmus** is the narrowest part of the fallopian tube, making it less accommodating for an ectopic pregnancy. - Pregnancies here tend to rupture earlier (typically by 6-8 weeks) due to limited space and thinner muscular walls. - Accounts for approximately 12% of tubal ectopic pregnancies. *Ampulla* - The **ampulla** is the most common site for ectopic pregnancies (approximately 70-80%), but pregnancies here typically rupture earlier than interstitial ones (usually by 8-12 weeks). - While wider than the isthmus, it lacks the substantial myometrial support of the interstitial portion. - The ampullary wall is thin and distensible but cannot sustain pregnancy as long as the interstitial portion. *Cornua* - While the interstitial part of the tube is located within the uterine wall (cornua), \"cornua\" itself refers to the upper angles of the uterus where the fallopian tubes enter. - The term **\"cornual pregnancy\"** is sometimes used interchangeably with **\"interstitial pregnancy,\"** though some authorities distinguish between them based on precise location. - Without the specific context of \"interstitial,\" this option is less precise in identifying the segment of the fallopian tube associated with prolonged survival.
Question 62: 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 63: 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 64: 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 65: 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 66: Which of the following describes the points marked in the diagram of pelvic measurements?
- A. Diagonal conjugate (Correct Answer)
- B. Obstetric conjugate measurement
- C. True conjugate measurement
- D. Oblique conjugate measurement
Explanation: ***Diagonal conjugate*** - The image depicts a **bimanual examination** where one hand is inserted vaginally to measure the distance from the **lower border of the pubic symphysis** to the **sacral promontory**. - This measurement directly corresponds to the **diagonal conjugate**, which is a clinically estimated measurement of the pelvic inlet. *Obstetric conjugate measurement* - The **obstetric conjugate** is the smallest anteroposterior diameter through which the fetal head must pass. - It extends from the **middle of the sacral promontory** to the **innermost aspect of the pubic symphysis** and cannot be measured directly by clinical examination. *True conjugate measurement* - The **true conjugate**, also known as the anatomical conjugate, extends from the **sacral promontory** to the **upper border of the pubic symphysis**. - Like the obstetric conjugate, it is not directly palpable and must be estimated from the diagonal conjugate (true conjugate = diagonal conjugate - 1.5 to 2 cm). *Oblique conjugate measurement* - The **oblique conjugate** measures the distance between the sacroiliac joint on one side to the iliopectineal eminence on the opposite side. - This measurement is not typically assessed during a routine pelvic examination as depicted and is more relevant for identifying asymmetric pelvic deformities.
Question 67: Which of the following is not considered an absolute contraindication for the use of an Intra Uterine Contraceptive Device (IUD)?
- A. Undiagnosed vaginal bleeding
- B. Pregnancy
- C. Pelvic inflammatory disease
- D. Uterine malformation (Correct Answer)
Explanation: ***Uterine malformation*** - While a uterine malformation can make IUD insertion more difficult or reduce its effectiveness, it is often considered a **relative contraindication**, depending on the specific anomaly and the patient's desire for contraception. - In certain cases, an IUD might still be a viable option, but it requires careful consideration and specialized insertion techniques. *Pregnancy* - The presence of an existing pregnancy is an **absolute contraindication** for IUD insertion, as it can lead to complications such as miscarriage or ectopic pregnancy. - An IUD is a contraceptive device, and inserting it when a woman is already pregnant directly contradicts its purpose and poses significant risks. *Undiagnosed vaginal bleeding* - This is an **absolute contraindication** because it could be a symptom of a serious underlying condition, such as cervical cancer, endometrial cancer, or ectopic pregnancy. - Inserting an IUD before diagnosing the cause of the bleeding could delay treatment of a potentially life-threatening condition and exacerbate the bleeding. *Pelvic inflammatory disease* - Current or recent (within the last 3 months) **pelvic inflammatory disease (PID)** is an **absolute contraindication** due to the increased risk of worsening infection. - IUD insertion can introduce bacteria from the vagina into the uterus, potentially exacerbating an existing infection or causing a new one.