Fetal kidney starts to produce urine by .... Week POG?

Appeared in: ESIC Nursing Officer 2016 (Shift -2)

Explanation

The fetal kidneys begin to produce and excrete urine by the 12th week of gestation.
This milestone marks the functional onset of the metanephros, which is the permanent kidney.
While initial glomerular filtration can start as early as the 9th week, 12 weeks is the standard timeframe for the commencement of significant urine production.
After this point, fetal urine begins to contribute to the volume of amniotic fluid.

Option A: At 10 weeks, the permanent kidneys (metanephros) are still in the early stages of development. While some initial glomerular filtration might be occurring, it is not yet established as consistent urine production.
Option C: By 14 weeks, urine production is already well underway. At this stage, the loop of Henle becomes functional, which is a more advanced step involving urine modification (reabsorption).
Option D: At 16 weeks, fetal urine is already the primary component of amniotic fluid. This indicates that urine production must have started significantly earlier.

Visual 1: Timeline Diagram - An infographic illustrating the key milestones of fetal kidney development from week 5 to week 18, highlighting the start of urine production at 12 weeks.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Fetal renal system development and the onset of urine production as background academic context rather than a clinical decision trigger.
Fetal urine production is the main source of amniotic fluid from the second trimester onwards. Assessing amniotic fluid volume is a key part of monitoring fetal well-being.
A low volume of amniotic fluid (oligohydramnios) can be a sign of fetal renal problems, such as bilateral renal agenesis (both kidneys missing) or a urinary tract obstruction.
Conversely, a high volume of amniotic fluid (polyhydramnios) can be associated with conditions that impair fetal swallowing, such as anencephaly.

How to Approach the Question

Identify the core of the question: it asks for the specific week of gestation when fetal kidneys start producing urine.
This is a factual recall question based on knowledge of fetal embryology and physiology.
Recall the major developmental milestones of the fetal organ systems.
Focus on the urinary system's timeline: the transition from primitive kidneys (pronephros, mesonephros) to the permanent kidney (metanephros).
Differentiate between the start of filtration (around 9 weeks) and the established production of urine (around 12 weeks).
Eliminate options that are clearly too late (14 and 16 weeks), as urine is already a major component of amniotic fluid by then.

Concept Tested & Keywords

Concept Tested: Fetal renal system development and the onset of urine production.
Stem keywords: Fetal kidney, produce urine, Week POG
Lead-in keywords: BEST, MOST RELEVANT CLUE

QMieiCRoMkGtMDNrcPhBl

Practise the full ESIC Nursing Officer 2016 (Shift -2)

Attempt every question from this paper in a timed mock, then review the full solution for each one.