Minipills, also called POP, Progestin Only Pills, are another type of birth control pill. Unlike the combination oral contraceptive pill, which uses synthetic estrogen and progestin, minipills contain progestin only. Your natural estrogen levels may remain in their normal monthly cycle on minipills, which is why breastfeeding women may take these contraceptive pills. Estrogen signals the release of breast milk, which must be unaffected if a woman plans on breastfeeding her newborn baby. Minipills work by creating a more challenging environment for sperm -- your cervical mucus will thicken and your endometrium (the lining of your uterus) will thin out. Most sperm can't make it past these unfriendly conditions to reach the egg, if it is present. Some women don't ovulate on the minipill, and some don't even have periods -- not everybody has the same experience with this contraceptive pill. Your symptoms may smooth out after a couple of months.
The dose of progestin that the minipill contains is lower than you'll find in the combination pill. In order to work effectively, it must be taken as prescribed to maintain an even level of progesterone every day. You can see in the graph how the estrogen levels rise and fall in a normal pattern, while the progesterone levels remain constant -- induced by the minipill. Since we all react to progesterone in different ways, your levels of breast pain may be less, get worse, or remain unchanged while on the minipill.
Breastfeeding itself may cause many sensations in the breast and nipple, so if you're taking minipills while nursing a baby, it may be hard to sort out what is causing any breast pain. Consult your obstetrician if you're concerned about breast and nipple pain during breastfeeding.
Changing Your Hormone Levels Changes Your Breast Pain
Hormones that influence the menstrual cycle also affect breast pain or breast tenderness in premenopausal women. When you take synthetic hormones in birth control pills or hormone replacement therapy (HRT) your cyclical rhythms will change. Sometimes taking a contraceptive pill will help relieve breast pain and sometimes it may make the pain worse. Give yourself time to let the new cycle establish itself with the pill and keep your doctor informed of your menstrual and breast pain symptoms. Get professional help if your symptoms don't improve, or if you run into problems.
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Breast Pain. MedlinePlus Medical Encyclopedia. National Institutes of Health. Last Updated: 12/31/2008.
Oral Contraceptives and Cancer Risk: Questions and Answers. National Cancer Institute. Reviewed: 05/04/2006.
The Menstruating Years. Pp. 17-18. Dr. Susan Love's Breast Book. Susan M. Love, M.D. Fifth Edition, 2010.