Comparative study of the effects of a progestogen-only pill containing desogestrel and an intrauterine contraceptive device in lactating women

Objective To evaluate the effects of desogestrel 75μg/day, as a progestogen-only pill compared with a copper-bearing intrauterine contraceptive device (IUCD) on lactation and to study the safety of both treatments in mothers and children. Transfer of etonogestrel to breast milk was studied in a subgroup of desogestrel users. The children were to be followed up until 2.5 years of age.

Design An open, non-randomised, group-comparative study in lactating women.

Setting University Hospital, Reykjavik, Iceland.

Participants A total of 83 lactating women; 42 received desogestrel and 41 had an IUCD inserted for seven consecutive treatment cycles of 28 days.

Methods Evaluation visits were planned at baseline and at the end of treatment cycles 1, 4 and 7. The amount of breast milk was determined by weighing the infants before and after feeding, at baseline and after treatment cycles 1 and 4. Milk samples were obtained at the same time for constituent measurements. Safety was studied by structured medical examinations and by recording adverse experiences in mothers and children.

Results There were no significant differences between the desogestrel and IUCD groups in composition and quantity of breast milk nor in growth and development of the children followed up to the age of 2.5 years. In the desogestrel group a slightly higher incidence of mild adverse experiences of a hormonal nature was reported among both mothers and infants. Of the children 82% were followed until 1.5 years of age and 50% until 2.5 years.

Conclusion The use of desogestrel 75μg/day did not change the amount and composition of breast milk nor did it affect growth and development of the breastfed children. It appears to be a safe and effective contraceptive method for lactating women