Single hormone birth control comes in the form of pills, the shot (Depo), the implant (Nexplanon) and the hormonal IUD. All single-hormone forms are progesterone only, compared to 2-hormone options which include estrogen and progesterone derivatives. The only two-hormone options are in pill, patch and ring form.

So what do you need to know? If you have a family or personal history of blood clots or stroke, high blood pressure or other heart history or if you smoke, it’s worth discussing single-hormone birth control with your doctor. The primary reason is that estrogen (which is found in two-hormone options) has a slight increased risk in clot formation, and adding that risk to other risk factors could increase your risk for clots.

The way single hormone options work varies based on type of contraception. However, the most effective forms are the implant and IUDs because they have the least room for human error (missed doses or missed shots). If you choose to use the pill, it’s still a wonderful form of contraception. However, you need to remember to take it within the same 1-3 hour time window every day for it to be effective (unlike the 2-hormone option which has a window of 24-hours).

The most common side effects of single—hormone options include irregular bleeding, worsening acne and increased incidence of ovarian cysts. If you experience increased duration of periods, increased blood loss, worsening cramps or other symptoms that you find unacceptable, talk with your doctor. There will likely be a contraception option out there for you that meets your needs.