Is it true that the size of your breasts will increase in size because of the birth control pill?
The quick answer is it's likely, but the extent to which breast size increases depends both on the woman and the type of birth control pill she uses. Estrogen and progestin, the hormones found in birth control pills, often lead to an increase in breast size that generally reverses after a few cycles or when the woman goes off the pill. One reason the breasts become larger and feel engorged is because the hormones in the pill cause edema, or fluid retention. When this is the case, breasts often feel smaller during the pill-free or placebo pill week. The estrogen and progesterone in birth control pills can also lead to breast tissue growth, in which case the change in breast size tends to be more constant. In either case, breast fullness may also be accompanied by breast tenderness (mastalgia) or tingling. When a woman chooses to stop taking the pill, these effects generally disappear.
If you are interested in going on the birth control pill, make sure to consult with your health care provider, and let her or him know about your needs and concerns regarding the pill or other birth control methods. Another consideration to discuss with your health care provider is dosage of hormones in the pill you take; generally the higher the dosage of hormones, the more likely it is you will notice an increase in breast size. To avoid this and other possible side effects including weight changes, spotting, headaches, mood changes, and nausea, health care providers try to prescribe the lowest dosage pill that will be reliable in preventing pregnancy. Some examples of these low-dose pills include progestin-only pills and combined oral contraceptive pills that only contain 20 mcg of estrogen.
If the possibility of larger breasts influences your decision to use birth control pills as your method of contraception, know that there are many other hormonal and non-hormonal options for pregnancy prevention. To learn more, try reading through the Go Ask Alice! Contraception category of Sexual and Reproductive Health archives.