A 30-year-old man is evaluated for 3 years of infertility. Both testes are of normal size, but the vas deferens cannot be felt on either side. Semen: volume 0.7 mL (low), pH 6.7, no sperm even after centrifugation, fructose absent. FSH, LH and testosterone are normal. Which test should be offered before assisted conception?

Testicular biopsy for maturation arrest

Y-chromosome microdeletion testing

Karyotype for Klinefelter syndrome

Reproductive physiology

18 NEET-PG practice questions on Reproductive physiology, part of Physiology. The first 18 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Hard
A 30-year-old man is evaluated for 3 years of infertility. Both testes are of normal size, but the vas deferens cannot be felt on either side. Semen: volume 0.7 mL (low), pH 6.7, no sperm even after centrifugation, fructose absent. FSH, LH and testosterone are normal. Which test should be offered before assisted conception?
1. ACFTR gene mutation testing
2. BTesticular biopsy for maturation arrest
3. CY-chromosome microdeletion testing
4. DKaryotype for Klinefelter syndrome
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Answer: A · CFTR gene mutation testing
Normal testes and hormones with azoospermia mean obstruction, not failure of sperm production. A low-volume, acidic, fructose-negative ejaculate shows that the seminal vesicles, which supply the alkaline, fructose-rich bulk of semen, are absent or blocked, and impalpable vasa point to congenital bilateral absence of the vas deferens. This is strongly linked to CFTR mutations, so the man and his wife are tested and counselled before sperm retrieval for ICSI.
- B: Biopsy is not needed here; spermatogenesis is presumed normal with normal testes and FSH.
- C: Y microdeletions cause non-obstructive azoospermia, usually with raised FSH.
- D: Klinefelter syndrome causes small firm testes with high FSH and LH.
Question 2 · Medium
A 30-year-old woman had a massive postpartum haemorrhage with hypotension and needed 6 units of blood at a district hospital. On day 5 her breasts remain soft and no milk has come in despite repeated attempts at breastfeeding. Deficiency of which hormone best explains this?
1. AOxytocin
2. BProlactin
3. CEstrogen
4. DProgesterone
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Answer: B · Prolactin
Severe hypotension around delivery can infarct the enlarged anterior pituitary of pregnancy (Sheehan syndrome). Failure of lactation is often the first sign, because lactotrophs no longer secrete prolactin, which is needed to start and maintain milk synthesis. Other anterior pituitary hormones may fail later, so cortisol and thyroid function should be checked. The posterior pituitary, which releases oxytocin, is usually spared.
- A: Oxytocin deficiency affects milk ejection, not milk production, and the posterior pituitary is usually spared.
- C: The fall of estrogen after delivery is what allows lactation to begin.
- D: The fall of progesterone after delivery is also a trigger for lactation, not a cause of failure.
Question 3 · Medium
Consider these statements about a normal 28-day ovarian and menstrual cycle: 1. Theca cells make androgens under LH, and granulosa cells aromatise them to estradiol under FSH. 2. Proliferation of the endometrium in the follicular phase is driven mainly by progesterone. 3. A sustained high estradiol level switches its pituitary feedback from negative to positive, causing the LH surge. 4. The fall of estrogen and progesterone after the corpus luteum regresses leads to menstruation. Which statements are correct?
1. A1 and 4 only
2. B2 and 3 only
3. C1, 3 and 4 only
4. D1, 2, 3 and 4
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Answer: C · 1, 3 and 4 only
Statements 1, 3 and 4 are correct. The two-cell, two-gonadotrophin model explains follicular estradiol, and a high estradiol level held for about two days triggers the LH surge that causes ovulation. When the corpus luteum regresses without hCG, estrogen and progesterone fall, the spiral arteries constrict and the functional endometrium is shed. Statement 2 is false: estrogen drives the proliferative phase, while progesterone produces the secretory changes of the luteal phase.
- A: Leaves out statement 3, which is true: estradiol positive feedback triggers the LH surge.
- B: Includes statement 2, which is false, and leaves out the true statements 1 and 4.
- D: Includes statement 2; endometrial proliferation is estrogen-driven.
Question 4 · Medium
A 29-year-old woman with a 6-week intrauterine pregnancy undergoes laparoscopy for a twisted ovarian cyst. The gynaecologist takes care to preserve the corpus luteum, whose progesterone output at this stage is kept up by a placental hormone. Through which receptor does that hormone act?
1. AProlactin receptor
2. BFSH receptor
3. CLH receptor
4. DTSH receptor
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Answer: C · LH receptor
hCG from the syncytiotrophoblast rescues the corpus luteum from regression and keeps it secreting progesterone in early pregnancy. hCG shares its alpha subunit with LH, FSH and TSH, and its beta subunit closely resembles that of LH, so it binds the LH/hCG receptor on luteal cells. Later in the first trimester the placenta takes over progesterone production, so if the corpus luteum is removed early, progesterone support is given.
- A: Prolactin receptors mediate milk synthesis, not luteal progesterone secretion.
- B: FSH receptors drive follicle growth; hCG does not act on them to any useful extent.
- D: Only very high hCG levels, as in molar pregnancy, cross-react with the TSH receptor.
Question 5 · Easy
In an IVF laboratory, a husband's washed sperm are incubated in a special medium for some hours before insemination so that they become able to fertilise an oocyte. In natural conception, this step, capacitation, normally takes place in:
1. AThe seminal vesicles
2. BThe female genital tract
3. CThe seminiferous tubules
4. DThe epididymis
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Answer: B · The female genital tract
Capacitation normally happens in the uterus and fallopian tubes, after the sperm have left the seminal plasma. Cholesterol and coating glycoproteins are removed from the sperm membrane, calcium enters and the sperm develop hyperactivated motility and become able to undergo the acrosome reaction. Seminal plasma contains decapacitation factors, which is why sperm are washed and incubated before IUI or IVF.
- A: The seminal vesicles add fructose-rich fluid; seminal plasma actually inhibits capacitation.
- C: The seminiferous tubules produce sperm by spermatogenesis; sperm there are immotile.
- D: The epididymis matures sperm and gives them forward motility, but they are not yet capacitated.
Question 6 · Hard
A 28-year-old woman at 32 weeks of pregnancy is admitted for observation after a minor road accident. She is comfortable, RR 16/min, SpO2 99% on room air, and the chest is clear. An arterial blood gas on admission shows pH 7.44, PaCO2 30 mmHg, HCO3- 20 mmol/L and PaO2 104 mmHg. What is the best interpretation?
1. ANormal compensated respiratory alkalosis of pregnancy
2. BPrimary metabolic acidosis with respiratory compensation
3. CMixed respiratory and metabolic alkalosis
4. DAcute respiratory alkalosis from pulmonary embolism
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Question 7 · Medium
A 25-year-old woman breastfeeding her 2-month-old notices that milk drips from her breasts whenever she hears her baby cry, even before the baby is put to the breast. Which mechanism produces this?
1. AMyoepithelial cells contracting under oxytocin
2. BAlveolar cells secreting under prolactin
3. CDuctal smooth muscle contracting under vasopressin
4. DAlveolar cells secreting under placental lactogen
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Question 8 · Medium
A 27-year-old gym trainer in Pune who has injected testosterone for 18 months to build muscle is seen for infertility. His testes are small and soft, and semen analysis shows severe oligospermia. Serum LH and FSH are low. Why has his sperm production fallen?
1. ADirect toxicity of androgen to germ cells
2. BObstruction of both vasa deferentia
3. CPrimary damage to the Sertoli cells
4. DFeedback suppression of LH and FSH
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Question 9 · Medium
A 24-year-old mother attending a PHC postnatal clinic has breastfed her 4-month-old exclusively, day and night, and has not had a menstrual period since delivery. What is the main mechanism of her amenorrhoea?
1. AOxytocin acting directly to block ovulation
2. BEndometrial injury sustained at delivery
3. CPersisting placental hormones suppressing FSH
4. DSuckling-induced prolactin suppressing GnRH pulses
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Question 10 · Easy
A 27-year-old woman trying to conceive records her oral temperature every morning on waking. On day 15 of her regular 28-day cycle the reading rises by about 0.4 °C and stays up until her next period. Which hormone causes this rise?
1. AEstradiol
2. BInhibin A
3. CLuteinising hormone
4. DProgesterone
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Question 11 · Medium
In a teaching session in the labour room, the registrar lists cardiovascular changes of normal pregnancy. 1. Cardiac output rises by 30-50%, largely by the middle of pregnancy. 2. Systemic vascular resistance falls. 3. Blood pressure is lowest in the second trimester. 4. Central venous and pulmonary capillary wedge pressures rise markedly. Which of these statements are correct?
1. A1, 2 and 3 only
2. B1, 2, 3 and 4
3. C1 and 2 only
4. D2, 3 and 4 only
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Question 12 · Hard
Free T4 2.4 ng/dL (normal 0.8-1.8) and TSH 0.05 mIU/L (normal 0.4-4.0) are found in a primigravida at 9 weeks admitted to the district hospital with severe vomiting, 4 kg weight loss and ketonuria. She has no goitre, no eye signs and no past thyroid illness; TSH-receptor antibodies are negative, and serum hCG is very high for her gestation. Ultrasound shows a single live intrauterine pregnancy with no molar change. Pulse is 104/min with a fine tremor, and she reports no palpitations before this pregnancy. She is rehydrated and given antiemetics and thiamine. What is the best plan for the thyroid results?
1. AStart propylthiouracil at once
2. BSupportive care; repeat thyroid tests in 4-6 weeks
3. CStart carbimazole at once
4. DArrange a radioiodine uptake scan
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Question 13 · Medium
Azoospermia on two semen analyses is found in a well-virilised man evaluated with his wife for three years of infertility. Both testes are 10 mL. FSH 28 IU/L (1.5-12), LH 6 IU/L (normal), testosterone 520 ng/dL (normal); karyotype 46,XY. Testicular biopsy shows tubules lined only by Sertoli cells, with normal Leydig cells. Why is his FSH raised while LH stays normal?
1. ALow testosterone feedback to the pituitary
2. BLow inhibin B output from the seminiferous tubules
3. CFaster GnRH pulses from the hypothalamus
4. DExcess oestradiol made by Leydig cells
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Question 14 · Medium
Serum creatinine 1.0 mg/dL and blood urea 28 mg/dL are reported in a primigravida at 32 weeks seen in the antenatal OPD; BP 128/80 mmHg, urine albumin nil, no oedema. The laboratory marks both values as normal against the non-pregnant reference range (creatinine 0.6-1.1 mg/dL). How should her creatinine be interpreted?
1. ANormal, because GFR falls in the third trimester
2. BNormal, since it lies inside the adult reference range
3. CHigh for pregnancy, as GFR normally rises by about half
4. DLow, reflecting haemodilution in pregnancy
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Question 15 · Easy
Which placental hormone, rising steadily through the second and third trimesters, is chiefly responsible for the maternal insulin resistance of pregnancy?
1. AOestradiol
2. BPregnancy-associated plasma protein A
3. CHuman chorionic gonadotropin
4. DHuman placental lactogen
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Question 16 · Easy
At a routine antenatal visit in a CHC, a primigravida at 30 weeks is worried because her haemoglobin has fallen from 12.6 g/dL at booking (10 weeks) to 11.2 g/dL. MCV is 88 fL, she has no symptoms, and the peripheral smear is normocytic and normochromic. Which change best explains the fall?
1. AIncreased red cell destruction in the spleen
2. BPlasma volume rising more than red cell mass
3. CReduced erythropoietin secretion
4. DIron diverted to the growing fetus
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Question 17 · Medium
On the fifth day after a home delivery in a village of Malappuram, a mother says her breasts have not filled and the baby seems hungry, though he latches well. She has continuing fresh bleeding per vaginum, and ultrasound shows a 3 cm piece of retained placental tissue in the uterus. Her blood loss at delivery was modest, she is haemodynamically stable, and she breastfeeds the baby every two hours. Her haemoglobin is 10.8 g/dL, and she has no headache or visual symptoms. Which mechanism best explains the failure of milk to come in?
1. APlacental progesterone still blocking milk secretion
2. BLack of oxytocin release from the posterior pituitary
3. CPituitary necrosis from postpartum bleeding
4. DPlacental dopamine suppressing prolactin
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Question 18 · Hard
As the medical officer in an infertility clinic at a district hospital, you see a couple trying to conceive for two years. The wife's cycles are regular but 35 days long, from the first day of one period to the first day of the next. Her husband's semen analysis is normal, her BMI is 23 kg/m2, she has no hirsutism or galactorrhoea, and a tubal patency test last month was normal. Her home urine LH kits have given unclear results. To confirm that she ovulates, on which day of her cycle should serum progesterone be measured?
1. ADay 28
2. BDay 21
3. CDay 14
4. DDay 35
Answer and explanation in LearnFree account

Reproductive physiology

A 30-year-old woman had a massive postpartum haemorrhage with hypotension and needed 6 units of blood at a district hospital. On day 5 her breasts remain soft and no milk has come in despite repeated attempts at breastfeeding. Deficiency of which hormone best explains this?

A 29-year-old woman with a 6-week intrauterine pregnancy undergoes laparoscopy for a twisted ovarian cyst. The gynaecologist takes care to preserve the corpus luteum, whose progesterone output at this stage is kept up by a placental hormone. Through which receptor does that hormone act?

In an IVF laboratory, a husband's washed sperm are incubated in a special medium for some hours before insemination so that they become able to fertilise an oocyte. In natural conception, this step, capacitation, normally takes place in:

A 25-year-old woman breastfeeding her 2-month-old notices that milk drips from her breasts whenever she hears her baby cry, even before the baby is put to the breast. Which mechanism produces this?

A 27-year-old gym trainer in Pune who has injected testosterone for 18 months to build muscle is seen for infertility. His testes are small and soft, and semen analysis shows severe oligospermia. Serum LH and FSH are low. Why has his sperm production fallen?

A 24-year-old mother attending a PHC postnatal clinic has breastfed her 4-month-old exclusively, day and night, and has not had a menstrual period since delivery. What is the main mechanism of her amenorrhoea?

A 27-year-old woman trying to conceive records her oral temperature every morning on waking. On day 15 of her regular 28-day cycle the reading rises by about 0.4 °C and stays up until her next period. Which hormone causes this rise?

Which placental hormone, rising steadily through the second and third trimesters, is chiefly responsible for the maternal insulin resistance of pregnancy?

At a routine antenatal visit in a CHC, a primigravida at 30 weeks is worried because her haemoglobin has fallen from 12.6 g/dL at booking (10 weeks) to 11.2 g/dL. MCV is 88 fL, she has no symptoms, and the peripheral smear is normocytic and normochromic. Which change best explains the fall?