The progestogen-only pill (mini-pill, e.g., norethisterone 350 mcg daily) prevents pregnancy primarily by:

• A Suppressing FSH and LH to inhibit ovulation, as with combined OCP
• B Inhibiting corpus luteum progesterone secretion
• C Thickening cervical mucus (making it hostile to sperm penetration) and altering endometrial receptivity ✓
• D Accelerating ovum transport through the fallopian tube

Explanation

Low-dose progestogen-only pills (POPs) work primarily by thickening cervical mucus (increases viscosity, reducing sperm penetration) and altering endometrial glandular secretion and stromal architecture, impairing implantation. Ovulation is suppressed inconsistently (in ~50% of cycles at low doses). In contrast, higher-dose progesterone implants (e.g., etonogestrel implant) reliably suppress ovulation. This is the basis for the strict 3-hour timing window for traditional POPs.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.