Progestins are female hormones your body produces and that can be produced synthetically. Progesterone is a hormone in the progestin family that is used in hormone replacement therapy for women after they undergo menopause and in some forms of birth control pills. Progesterone-containing pills are prescribed for a number of health conditions, including if you have stopped menstruating, which can indicate a lack of progesterone in the body.
Estrogen-Progestin Pills
Most birth control pills are known as combination pills, which contain estrogen and progestin -- the synthetic version of progesterone. The estrogen in the pills works to stop the pituitary gland from releasing hormones that can stimulate ovulation. However, estrogen can have some side effects, like thickening the uterine lining, which can increase a released egg's likelihood of attaching to the uterus. This is where progestin comes in: the progestin helps reduce the uterine lining, making the environment inhospitable for an egg to implant, therefore preventing pregnancy.
Progestin-Only
While some pills combine hormones like progesterone and estrogen, others include only progestin. Progestin-only pills are known as "mini-pills." These pills trick your body into thinking it's pregnant, thin the uterine lining and increase the mucus between the uterus and vagina, making it more difficult for an egg to pass through. Physicians prescribe the progestin-only pill in a few key situations: if you are breastfeeding or if you have severe reactions to estrogen-progestin pills. Also, progestin-only pills are considered safer for women older than age 35 as there is an increased risk of side effects when taking the pill past this age.
Progestin-Only Drawbacks
While the progestin-only pill offers several benefits, it also can be more complicated to take than an estrogen-progestin combination pill. This is because you must take a progestin-only pill every day at the same time. Combination pills tend to have a larger window where you can take them around the same time each day and still have a higher chance of preventing contraception. If you have difficulty remembering to take medication or taking it at the same time each day, the progestin-only pill may not be for you. Also, the estrogen in the combination pill helps prevent breakthrough bleeding, which can occur when you take birth control pills.
Warning
Before you take progestin-containing pills, inform your physician about any medications you may be taking, including St. John's wort or other herbal supplements. Medications like amiodarone, fluconazole, itraconazole or troleandomycin may affect how well your birth control pills work, and your physician may need to adjust your medications accordingly.
References
- Family Doctor: Progestin-Only Contraceptives; July 2010
- Baby Center: Birth Control Pills; The Minipill; June 2006
- MedlinePlus: Estrogen and Progestin; February 2011
- PubMed Health: Progesterone; September 2008
- American Pregnancy Association: Oral Contraceptives: Birth Control Pills; August 2003
- Go Ask Alice!: How Do Birth Control Pills Work?; April 2010
