Is time-interval between mini-pill ingestion and breastfeeding essential?

A study was conducted on four alternate days over an eight-day period in a group of 12 healthy, 20-35 year old exclusively breast feeding women who were interested in weaning their infants. On each study day the women ingested 150 micrograms levonorgestrel. Maternal blood and milk samples were collected at 2, 4, 6, and 8 hr intervals after LNG ingestion on the 1st, 3rd, 5th, and 8th day. A time-dependent decrease in maternal serum and increase in breast milk levels of LNG were observed. Maintaining a time interval between mini-pill intake and breastfeeding results in higher levels of LNG in breast milk, thereby exposing the infant to a bolus of LNG in a "single-delayed" feed.