Under the National Family Planning Programme, the injectable contraceptive Antara Program (medroxyprogesterone acetate) is administered as a single intramuscular dose of 150 mg. Its primary mechanism of action is:

• A Thickening of cervical mucus preventing sperm penetration only
• B Suppression of ovulation by inhibiting gonadotropin release ✓
• C Induction of endometrial atrophy preventing implantation only
• D Direct spermicidal action in the uterine cavity

Explanation

Medroxyprogesterone acetate (DMPA), the injectable contraceptive under India's Antara Program, acts primarily by suppressing the hypothalamic-pituitary axis, inhibiting gonadotropin release and thus preventing ovulation. While it also thickens cervical mucus and causes endometrial atrophy, suppression of ovulation is the principal mechanism. Option A and C describe secondary mechanisms only. Option D is incorrect as DMPA has no spermicidal action.

Reference: Park's Textbook of Preventive and Social Medicine, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.