Q.19 Presence of which one of the following in the urine indicates pregnancy in human?
(A) Progesterone (B) Follicle–stimulating hormone and luteinizing
hormone
(C) Estrogen (D) Human chorionic gonadotropin
Human chorionic gonadotropin (hCG) in urine is the definitive indicator of pregnancy, as it is produced by the developing placenta shortly after implantation. This makes option (D) correct for the CSIR NET Life Sciences question.
Option Analysis
Progesterone (A): Progesterone maintains the uterine lining post-ovulation and during early pregnancy but circulates mainly in blood, not excreted detectably in urine for pregnancy tests.
FSH and LH (B): Follicle-stimulating hormone (FSH) stimulates follicle growth, while luteinizing hormone (LH) triggers ovulation; both are present in menstrual cycles but not uniquely elevated or urine-detectable for confirming pregnancy.
Estrogen (B): Estrogen supports endometrial proliferation and pregnancy but exists at baseline levels throughout cycles and is not the specific urine marker for pregnancy detection.
Human Chorionic Gonadotropin (D): hCG, produced by trophoblast cells post-implantation, appears in urine 5-7 days after conception (around first missed period) and is detected by standard pregnancy tests at levels >20-50 mIU/mL.
Human chorionic gonadotropin urine pregnancy tests revolutionized early detection by identifying hCG, the hallmark hormone produced exclusively after implantation. For CSIR NET Life Sciences aspirants, understanding this biomarker distinguishes it from other hormones like progesterone or estrogen.
hCG Role in Pregnancy Detection
The placenta secretes hCG starting 6-10 days post-conception, peaking at 8-10 weeks before declining. Urine tests detect beta-hCG subunits, reliable from the first missed period with >99% accuracy if used correctly.
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Home kits use immunoassay strips for qualitative results (positive/negative).
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Blood tests quantify levels, doubling every 48 hours in viable pregnancies.
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False negatives occur early or with dilute urine; false positives from medications or ectopic issues.
Why Not Other Hormones?
Progesterone sustains pregnancy but lacks urine specificity. FSH/LH regulate cycles, not implantation. Estrogen rises gradually without unique urine presence.
| Hormone | Primary Function | Urine Presence in Pregnancy? |
|---|---|---|
| Progesterone (A) | Uterine maintenance | Low, not diagnostic |
| FSH/LH (B) | Ovulation/follicle growth | Cycle-related, not specific |
| Estrogen (C) | Endometrial growth | Baseline levels |
| hCG (D) | Pregnancy confirmation | Detectable marker |
CSIR NET Exam Relevance
This question tests reproductive endocrinology: hCG rescues corpus luteum, preventing menstruation. Master pathways for molecular biology/biochemistry sections.
