Oral contraceptive pills that contain progestin, which is the synthetic equivalent of the natural hormone progesterone, are sometimes called minipills. Unlike other birth control pills, progestin-only pills do not contain the hormone estrogen and contain lower doses of progestin than contraceptives that contain both estrogen and progestin. This type of contraception may be very helpful to women with medical conditions that may be worsened by estrogen; it is also used to treat endometriosis. However, the progestin-only oral contraceptive may cause several side effects that are uncomfortable or unpleasant.
Changes in the Menstrual Cycle
Dr. Andrew Kaunitz, writing in the medical reference UpToDate, explains that a common side effect of any progestin-only contraceptive--whether a pill or an implanted device such as an intruterine device--is that of irregular menstrual cycles. Depending on the patient, this may mean that she experiences spotting, unscheduled or unexpected bleeding or a complete cessation of menstrual cycles. The latter may be a convenient effect but may also cause stress if the reason for an absent period is thought to be due to an unplanned pregnancy. These unpredictable changes may be significant enough that the patient decides to choose another type of contraception. Indeed, Dr. Kaunitz indicates in his article for UpToDate that menstrual cycle unpredictability is the most frequent reason for discontinuing progesterone-only contraceptives, including the progestin-only pill.
Acne
The National Institutes of Health website, Medline Plus, lists acne as another possible side effect of progestin-only pills. In his UpToDate article, Dr. Kaunitz suggests that this may be due to the fact that progesterone has androgenic effects. These are effects that are associated with the production of male sex hormones such as testosterone. While this side effect may not be dangerous or painful, it can certainly be unpleasant or, in severe cases, disfiguring. Patients who are experiencing severe acne as a result of taking oral progestin-only contraceptives may consider switching to another form of birth control.
Unwanted Hair Growth
Excessive hair growth is known as hirsutism. Women who take a progestin-only contraceptive pill, whether for prevention of unwanted pregnancy or to treat endometriosis, may find that that they have more hair growth than usual. In some cases, they may even notice the growth of facial hair. Similarly to the situation with acne, this is likely due to the androgen-like effects of progesterone; if a patient is suffering from this side effect and wants to discontinue her use of the progestin-only oral contraceptive, she should discuss this with her healthcare provider.
References
- Medline Plus: Progestin-Only Oral Contraceptives
- "UpToDate;" Progestin-Only Pills (Minipills) for Contraception; A. Kauntiz; February 2010
- Medline Plus: Norethindrone
