The scenario:
A 25 year-old patient (she/her) is interested in starting birth control four weeks after having her first child. She is breastfeeding but needs to supplement formula one to two bottles a day because of “not having enough milk.” Prior to pregnancy she was happy with a hormonal implant but is unsure if this method is safe while producing milk.
Is birth control safe during lactation*?
Hormonal birth control has long been considered safe to use during lactation for both parents and infants. Parent safety includes risk to the health of the birthing person, including high blood pressure and blood clots, the likelihood of which are elevated in the postpartum time period. Infant safety includes potential for harm from exposure to hormonal birth control (considered low) as well as losing the benefit of exclusive feeding with human milk. Individual decisions about birth control also go beyond safety and include considerations of how birth control can affect milk supply.
Parent safety
Birth control safety in the postpartum period depends on the type of hormonal birth control used, how long it’s been since delivery, if someone is lactating, and an individual’s risk of venous thromboembolism (VTE). However, by 42 days postpartum, all birth control methods can be used by people who are lactating without restrictions according to the U.S. Medical Eligibility Criteria for Contraceptive Use (as long as they don’t have other contraindications).
Progestin-only options, including the progestin-only pill, implant, shot, and hormonal IUD, can all be started immediately postpartum and have less of a risk in decreasing milk production; however counseling should include that there is a risk of decreased supply and how to quickly change methods should this occur. All non-hormonal and behavioral methods are safe to use in the postpartum period and offer the least risk of impacting milk supply.
Infant safety
All birth control methods are safe to use while lactating in terms of infant safety. No progesterone only method has been noted to show differences in growth or development when compared with other babies whose parent was not taking a hormonal birth control method. Use of estrogen-containing methods are also safe—the exposure is low because estrogens are not excreted into milk at a high level. There are case reports of neonatal breast development with combination pill use; however, that subsides when pills are stopped and there were no differences in growth or development noted. For more information about the safety of individual methods (and other medications), the National Center for Biotechnology Information has a free online database.
How does hormonal birth control affect milk supply?
Although all methods of birth control are safe from an exposure standpoint, a reduction in the amount of milk can lead to an increased need for supplementation and eventually early weaning if not recognized.
Progesterone and estrogen are important hormones in pregnancy and lactation. An increase in these hormones after delivery can both impede lactogenesis II, which is needed for the production of milk after delivery, and limit the amount of milk that is produced. However, there is variability between individuals in the amount that exogenous estrogen and progestin decrease milk supply.
While all estrogen-containing methods, such as combination pills, patches, and rings, will cause a decrease in the amount of milk produced, combination pills are the most likely to cause a decrease in milk production. As such, combination pills can be utilized if someone wants to stop milk production altogether. Some progestin-only methods have also been documented to decrease milk supply. Of all the progestin-only methods, the shot has the greatest risk for milk supply reduction, and the implant is slightly more likely than a hormonal IUD to cause a decrease in the amount of milk produced. However, the studies looking at these effects have very small sample sizes and are limited.
What about the lactational amenorrhea method (LAM)?
Lactation in and of itself can serve as highly effective birth control. LAM is 98% effective at preventing pregnancy if the following three criteria are met:
- There is no return of menses.
- All infant nutrition is from human milk directly (versus expressed milk) with no more than four hours between feedings, including overnight.
- The infant is less than six months of age.
However, as soon as any one of these criteria are not met (for example, the patient in this scenario), particularly if milk removal is spaced out overnight, LAM quickly loses its efficacy. Education on LAM should include information on how to follow up in the first six months for alternative birth control options, including hormonal and non-hormonal options, if any of these criteria are no longer met.
Back to the scenario–do you offer this patient another implant?
It depends on what she wants! Although the implant is safe during lactation, it may affect the amount of milk she produces.
It is important to ask questions to understand her birth control preferences as well as her long- and short-term goals for lactation. Counseling should include information on the safety of all methods, consideration of how starting an implant today could impact milk production, and how that may impact long-term breastfeeding goals. However, if the supplementation is going well and the patient feels that the most important aspect of today’s visit is avoiding pregnancy, an implant may be the best option. What is most important is giving her the best information so that she can choose the method that’s right for her based on her contraceptive needs and her goals for lactation.
Key Points
- Most hormonal birth control methods are safe to use while lactating.
- Some hormonal methods can affect milk supply, especially combination estrogen-progestin options and, to a lesser extent, certain progestin-only methods like the shot or implant.
- Lactational amenorrhea method (LAM) is highly effective, but only under certain conditions. Once supplementation begins or feedings are spaced out, effectiveness drops significantly.
- Counseling should balance contraceptive needs and lactation goals, supporting informed decisions based on the patient’s values, experiences, and evolving priorities.
*We know that words matter, and we aim to use the most inclusive language on Bedsider Providers. In this article, we are using lactation to include anyone who is giving human milk through direct chest or breastfeeding as well as those who are giving expressed milk.