Figure 3.

Representative hormone, mucus, and menses profile of a woman with follicular activity and delayed ovulation (green, yellow, blue as described in Figure 1, red represents menses). Two arrows represent the end of full breastfeeding with the introduction of formula or solids (3.0 months) and complete weaning (4.1 months). The short time span between the two landmarks indicates that breastfeeding intensity decreased rapidly, thereby probably stimulating reactivation of the hypothalamic–pituitary–ovarian axis. The dotted line is the PDG threshold of 9 µmol/24 h as the biochemical criterion of ovulation. PDG = pregnanediol glucuronide.