Hormonal contraceptive measures can be used immediately postpartum if the patient so desires. Progestin-only contraceptives are preferable to estrogen-containing methods if initiated during the first six months after delivery. Progestin only contraceptives do not appear to affect milk volume, composition, or to cause deleterious effects in the infant. Ideally for women who desire a form of contraception in addition to lactation-induced amenorrhea, progestin-only methods should be started at six weeks postpartum if the woman is fully breastfeeding. Since contraception protection is provided by lactation amenorrhea, the six week delay will decrease infant exposure to exogenous hormones and decrease the incidence of irregular postpartum bleeding. Milk volume may decrease with the use of estrogen; however, no detrimental effects have been shown on infant growth or development. For women who are planning to gradually wean their infant, use of COCs may provide an easier transition to bottle-feeding. COCs should be used with caution by women who are not able to obtain supplemental milk. A decrease in milk volume can lead to earlier discontinuation of the hormonal contraceptive in an attempt to increase milk quantity. Supplementation is often needed, and then the woman ovulates again, possibly resulting in an unintended pregnancy. Many women are motivated immediately postpartum to accept contraception. For other women, lack of access to health care may provide barriers in obtaining adequate contraception later. In either case, there are adequate data to show no detriments of starting progestin-only contraceptives within days of delivery. Therefore, the best method for the patient should be employed to ensure adequate contraception while preserving optimal lactation.
PIP: This review covers the appropriateness of the use of hormonal contraceptive methods while breast feeding. The introduction notes that exclusive breast feeding is associated with a pregnancy rate of less than 2% during the first 6 months postpartum. While infertility associated with amenorrhea may be extended by breast feeding on demand continually during the day and night, this is often impractical for women in developed countries. Research on progestin-only contraceptives indicates that use of norgestrel may enhance lactation and is associated with no difference in milk content from controls. Use of levonorgestrel was associated with decreased milk volume but no differences in length, weight, or head circumference of subject infants. Injections of NET-EN or depot medroxyprogesterone at 1 and 6 weeks postpartum led to no adverse effects on infants or lactation. In addition, Norplant implants after the 4th week postpartum had no affect other than passing on a small dose to the infant, which is associated with no health risk. Use of a progestin-releasing IUD in comparison with a copper IUD was associated with a slight decrease in milk volume. Nearly all studies have concluded that combined oral contraceptives decrease milk volume and impair a woman's ability to breast feed exclusively. Thus, hormonal contraceptives can be used immediately postpartum and progestin-only contraceptives are preferable during the first 6 months because they have no apparent deleterious effect on breast feeding.