Side Effects of Birth Control Pills While Breastfeeding

When a nursing mother is evaluating medications for herself, she must consider how possible side effects will impact her as well as her child. Many medications, including hormonal birth control pills, can pass through her breast milk to her child. Awareness of the side effects can help her to make an educated decision that will allow her to manage her fertility and continue to enjoy a breast feeding relationship with her child.

What Kind of Pill? Combo Versus Progesterone Only

When evaluating the side effects of birth control pills, one must first look at the type of pill that the nursing mother will be using. There are two main types of birth control pills available. The most commonly prescribed is a combination of estrogen and progesterone. These pills are available under many names and are considered a reliable way to prevent pregnancy. However, estrogen is not recommended for nursing mothers because it is known to greatly reduce a mother’s milk supply.

Instead, care providers often prescribe progesterone only pills to nursing mothers. These have a slightly higher failure rate (because the lower hormone dose makes them more subject to user error), however they are considered compatible with lactation because progesterone does not seem to interfere with milk supply to the extent of estrogen.

Side Effects for the Nursing Mom

While both progesterone and estrogen are approved by the American Academy of Pediatrics for use by breastfeeding women, one important side effect that pertains to nursing mothers is the dramatic drop in milk supply that estrogen causes. If a woman chooses to use combination birth control containing estrogen and progesterone, it should only be used after the nursing baby reaches six months old and is well established on solid foods, according to Kelly Bonyata, International Board Certified Lactation Consultant.

In addition to the potential drop in supply, a woman must also be aware of the side effects of birth control that pertain to all users, regardless of lactation status. These include irregular bleeding or spotting, nausea, breast tenderness, weight gain, water retention, spotty darkening of the skin, and mood changes. There are also important danger signs that can identify a more dangerous reaction, such as a blood clot. These signs include severe abdominal pains, chest pain, shortness of breath, severe headaches, eye problems (such as blurred vision) or severe leg or arm pain or numbness.

Side Effects for the Breastfed Baby

The most obvious side effect of birth control pills on the breastfed baby is the potential for a drop in milk supply in the mother. This drop in supply could lead to poor growth, lack of nutrition, and an end of the breastfeeding relationship. There have been few studies to directly study long term effects of early exposure to these hormones, although the American Academy of Pediatrics regards them as safe for the nursing infant.