‘Pregnancy Test’ is based on estimation of the following hormone - - UPPSC 2023

UPPSC 2023

Obstetrics & Gynaecology

Easy

Appeared in: UPPSC 2023

Explanation

Pregnancy tests are designed to detect Human Chorionic Gonadotropin (hCG), a hormone produced by the placenta's syncytiotrophoblast cells after implantation.
hCG can be detected in the mother's blood and urine as early as 7 to 9 days after ovulation, making it the earliest biochemical marker of pregnancy.
The primary function of hCG is to maintain the corpus luteum, which in turn produces progesterone to support the uterine lining and sustain the early pregnancy.
The unique beta (β) subunit of the hCG molecule is what pregnancy tests specifically target, allowing them to distinguish it from other similar hormones like Luteinizing Hormone (LH).

Option A: Luteinizing Hormone (LH) is incorrect because its primary role is to trigger ovulation. Its levels peak before conception occurs.
Option B: Progesterone is incorrect because while it is essential for maintaining the uterine lining and supporting the pregnancy, it is not the specific marker used for the initial detection of pregnancy.
Option D: Follicle-Stimulating Hormone (FSH) is incorrect because its main function is to stimulate the growth of ovarian follicles at the beginning of the menstrual cycle, well before pregnancy is established.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal basis of pregnancy detection as background academic context rather than a clinical decision trigger.
Quantitative blood tests for hCG (beta-hCG) are vital for monitoring early pregnancy. A normal doubling time (approximately every 48-72 hours) is a strong indicator of a viable intrauterine pregnancy.
Abnormally rising or falling hCG levels are a critical warning sign. Slow-rising levels may indicate an ectopic pregnancy or a non-viable pregnancy, requiring urgent medical evaluation.
Extremely high hCG levels for gestational age can be a marker for a multiple gestation (e.g., twins) or, more concerningly, gestational trophoblastic disease (a molar pregnancy).

How to Approach the Question

This is a factual recall question testing fundamental knowledge of reproductive physiology.
First, identify the key terms in the question: 'Pregnancy Test' and 'hormone'. The question asks which hormone is measured to confirm pregnancy.
Recall the timeline of early pregnancy: ovulation, fertilization, implantation, and the beginning of placental development.
Remember that the newly formed placenta must send a signal to the mother's body to prevent menstruation and maintain the pregnancy. This signal is a specific hormone.
Associate this unique pregnancy-signaling hormone with Human Chorionic Gonadotropin (hCG).
Systematically eliminate the other options by recalling their primary functions: FSH and LH are key players before ovulation, and while progesterone is vital during pregnancy, it's not the primary detection marker.

Concept Tested & Keywords

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