Journal: Cochrane Review
Authors: Laureen M Lopez, Thomas W Grey, Alison M Stuebe, Mario Chen, Sarah T Truitt, Maria F Gallo
Plain Language Summary:
Hormonal and nonhormonal birth control during breastfeeding
Birth control for women who are breastfeeding is important worldwide. Delaying the next pregnancy improves the health of women and children. Each year, millions of women decide whether to use birth control after having a baby. The decision includes the birth control type and when to start using it. Researchers and health care providers debate these issues. Some worry that hormones could affect the breast milk and therefore the baby’s growth. Ideally, the birth control would not affect the type or amount of breast milk or the baby’s growth. Identifying the best time to start birth control is also important. When monthly cycles return is uncertain, and the woman could get pregnant again.
Combined birth control methods contain the hormones estrogen and progestin. Other types of birth control contain only progestin or no hormones. We looked at whether combined birth control or methods with only progestin affect breastfeeding more than other methods. We ran computer searches for randomized trials of birth control used during breastfeeding until 2 March 2015. These trials compared hormonal methods to other hormonal methods or to placebo (‘dummy’ method). We also looked at reference lists to find trials. For the initial review, we wrote to researchers to find other studies.
We included 11 studies with a total of 1482 women. These trials looked at many methods: pills, an implant, the injectable ‘Depo,’ and a hormonal intrauterine device (IUD). Some older reports did not have much data. Most trials showed no major difference due to hormonal birth control use. Two of eight trials noted less breastfeeding among women using hormonal birth control. One was a combined pill with few results and the other a hormonal IUD. In one study, the implant group infants gained more weight than those in the no-method group but less weight than infants in the ‘Depo’ group. Two trials noted that a combined pill had a negative effect on breast milk volume or content. One report did not have much data. The other showed lower volume for combined pill users than for women taking pills with only progestin.
We found little information on any specific birth control method, with usually two studies per method. Results were not consistent across all trials. The data were of moderate quality overall. The results of better quality showed little effect on breastfeeding or infant growth.