The fetal kidneys start providing urine at
A. 12 week
B. 8 week
C. 14 week
D. 10 week
Correct Answer: B. 8 week
Explanation
Question: The fetal kidneys start providing urine at which week of gestation?
Correct answer: Around 10–12 weeks of gestation
(Most exam keys accept 10 weeks as the best answer)
Explanation
- The permanent kidneys (metanephros) begin to develop around the 5th week of intrauterine life.
- Although kidney structure starts forming early, functional urine production begins later.
- By about 10–12 weeks, the fetal kidneys start producing urine, which then becomes the main contributor to amniotic fluid.
Why earlier weeks are incorrect
- Before 10 weeks:
- Kidneys are still developing
- Urine production is minimal or absent
- Amniotic fluid mainly comes from maternal sources and transudation
Key points to remember
- Kidney development: starts at 5 weeks
- Urine formation begins: 10–12 weeks
- Amniotic fluid later in pregnancy depends largely on fetal urine
One-line exam answer
Fetal kidneys start producing urine at about 10 weeks of gestation.
Key points (≈50 words, point-to-point):
• Fetal kidneys (metanephros) begin functioning around 10 weeks.
• Urine formation starts and contributes to amniotic fluid.
• Before this, amniotic fluid is mainly from maternal sources.
• Urine production increases as gestation advances.
Other Options Details
Question: The fetal kidneys start providing urine at — describe all options.
A. 12 weeks
- By 12 weeks, the fetal kidneys are actively producing urine.
- Urine production is well-established and contributes significantly to amniotic fluid volume.
- This option is slightly late for the start of urine production.
B. 8 weeks
- At 8 weeks, kidney development is still in the early embryonic stage.
- The permanent kidney (metanephros) has begun forming, but it is not yet functional.
- Urine production has not started at this stage.
- ❌ Incorrect.
C. 14 weeks
- At 14 weeks, fetal kidneys are fully functional in terms of urine formation.
- Amniotic fluid is largely maintained by fetal urine.
- This is much later than the starting point.
- ❌ Incorrect for “start”.
D. 10 weeks ✅ Correct Answer
- The fetal kidneys (metanephros) begin producing urine around the 10th week of gestation.
- This marks the onset of renal function in the fetus.
- Fetal urine gradually becomes the main source of amniotic fluid after this time.
✅ Correct Answer: D. 10 week
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Writer: Vandita Singh, Lucknow (GS India Nursing Group