Is Opill As Effective As Other Birth Control Pills?

Quick Answer

Opill, a progestin-only pill, is approximately 98% effective in preventing pregnancy but is less forgiving in terms of missed or late doses compared to combined hormone birth control pills (i.e., those that contain both progestin and estrogen).

Detailed Answer

Opill is a progestin-only pill, also known as a mini pill or POP (progestin-only pill). Unlike combined hormone pills that contain both estrogen and progestin, progestin-only pills only contain progestin and do not include estrogen.

Progestin-only pills like Opill primarily work by thickening the cervical mucus, making it difficult for sperm to reach the egg. They also thin the lining of the uterus, reducing its receptiveness to implantation. These mechanisms help prevent pregnancy. Some progestin-only pills suppress ovulation, but most do not.

Most sources report that when taken correctly, progestin-only pills are around 99% effective in preventing pregnancy.

Clinical trials for Opill specifically, involving more than 2,000 women aged 15 to 49 years old (over 21,000 28-day cycles), reported a pregnancy rate of 2 percent, indicating an effectiveness rate of around 98% in preventing pregnancy.

Effective But Less Margin For Error

Progestin-only pills, like Opill, can be highly effective in preventing pregnancy when taken correctly. However, they have a narrower margin for error compared to combined hormone pills.

Progestin-only pills require strict adherence to a daily dosing schedule. Deviating from the recommended timing, even by a few hours, or missing doses completely, can significantly decrease their effectiveness.

In contrast, combined hormone pills are generally more forgiving if a pill is missed or taken slightly outside the designated time window. However, it is still important to follow the instructions provided with any birth control pill to maximize its effectiveness.

Other Differences Versus Combined Hormone Pills

There are a few notable differences between progestin-only pills, like Opill, and birth control pills that contain both estrogen and progestin I want to point out here (in addition to the fact that progestin-only pills are less forgiving with missed doses):

• In contrast with estrogen-progestin oral contraceptive pills, most progestin-only pills do not consistently suppress ovulation. The effectiveness of progestin-only pills in preventing pregnancy primarily relies on their effects on cervical mucus and the endometrium.
• Unscheduled bleeding (e.g., spotting, breakthrough bleeding) and menstrual changes are fairly common in progestin-only pill (POP) users. In fact, menstrual irregularities are a common reason for discontinuation of progestin-only pills.

Final Words

Opill, as a progestin-only pill, is an effective birth control option with an approximately 98% success rate in preventing pregnancy.

Although you don't need a prescription for Opill, if you have concerns or questions about taking it, I recommend you speak with your doctor for personalized advice.