Explaining Saheli Like a 10-Year-Old
Imagine the uterus as a room with a "Welcome" mat for an embryo to move in (implant). The embryo can only move in when the room has been prepared by estrogen (the interior decorator).
Regular hormonal pills (OC pills) work like this: they flood the body with fake estrogen and progesterone. The brain thinks: "Oh, there's already lots of these hormones — no need to release LH and FSH." Without LH, ovulation doesn't happen. No egg = no fertilization = no embryo.
Saheli (centchroman) works differently: it does NOT stop the egg from being made. Instead, it goes into the "room" (uterus) and REMOVES the "Welcome" mat (blocks estrogen receptors). So even if an embryo forms and arrives, the room doesn't recognize it and the embryo cannot implant.
Why NEET Tests This
Students memorize "oral contraceptive = prevents ovulation." Saheli breaks this rule completely. Saheli:
- Does NOT prevent ovulation
- Does prevent implantation
- Is NOT a steroid hormone
- Does NOT suppress GnRH/LH/FSH
Comparison Table
| Feature | OC Pills (Combined) | Saheli |
|---|---|---|
| Type | Steroidal (progestogen + estrogen) | Non-steroidal (centchroman) |
| Mechanism | Suppresses ovulation (via gonadotropin inhibition) | Prevents implantation (via estrogen receptor blockade) |
| Dosing | Daily | Once weekly (after loading phase) |
| Developer | Pharmaceutical companies (various) | CDRI, Lucknow |
| STD protection | None | None |
| Reversibility | Reversible (stop taking) | Reversible (stop taking) |
NEET Trap Answer
Q: Saheli prevents pregnancy by suppressing LH release. A: FALSE. Saheli works by blocking estrogen receptors → prevents implantation. LH suppression is the mechanism of OC pills.