A review of the use of progestogen-only minipills for contraception during lactation

Abstract

Progestogen-only minipills and other systems for releasing low doses of progestogens alone are widely used for contraception in breast-feeding women around the world. There is good evidence to confirm their acceptability and their lack of effect on milk production, neonatal growth and early development. In contrast, combined oral contraceptives frequently decrease milk production, and may produce minor changes in milk composition. However, even combined oral contraceptives do not appear to produce adverse effects on neonatal well-being and development, although minor reductions in initial growth rate may sometimes occur. Progestogen-only methods may also produce subtle changes in milk composition, although less than combined oral contraceptives. Steroids are transferred from plasma into milk in small quantities, but the amounts are usually very low or insufficient to allow detection in the infants using present-day assays. There has been theoretical concern that these tiny amounts of steroids might affect neonatal reproductive development, but this appears to be unwarranted. Progestogen-only methods are being widely used for post-partum contraception, and they appear to have particular advantages in this situation. They also have few disadvantages; a theoretical concern about a possible effect on later reproductive or sexual development has no evidence to support it. The present licensing situation in Australia, which lists lactation as a relative contraindication to progestogen-only contraceptive use, causes real concern to potential users and appears to lead to frequent errors in compliance.