What is the Origin of Progestin-Only Pills?

POPs were developed as an alternative to Combined Oral Contraceptives (COCs) to mitigate the potential risks associated with the estrogen component, particularly cardiovascular complications. Early research focused on identifying progestin dosages and formulations that could reliably prevent pregnancy primarily through peripheral mechanisms. This development expanded contraceptive access for specific populations previously excluded from combined hormonal methods.

What is the Mechanism of Progestin-Only Pills?

The primary contraceptive mechanism of POPs is the thickening of the cervical mucus, creating a barrier that prevents sperm penetration into the upper reproductive tract. Additionally, progestin suppresses the endometrial lining, making it unreceptive to implantation. While some formulations may suppress ovulation in a percentage of cycles, this effect is less consistent than with COCs, making the cervical mucus barrier the most reliable action.

Progestin-Only Pills ∞ Area

Progestin-Only Pills

Meaning

Progestin-Only Pills (POPs), often referred to as the mini-pill, are a form of oral hormonal contraception containing only a synthetic progestin and no estrogen component. These pills are a valuable option for women who have contraindications to estrogen, such as those with a history of thromboembolism or who are breastfeeding. Consistent, timely daily intake is critical for maintaining their contraceptive efficacy due to their short half-life.