Their use has been shown to decrease both the quantity and quality of breast milk. Use during lactation is not recommended. Other commonly reported adverse effects included headache, nausea, vomiting, dysmenorrhea, breast pain and edema. DNA, RNA and various proteins are increased by estradiol in target tissues. Norethindrone acetate blocks follicular maturation and ovulation by preventing the secretion of pituitary gonadotropins.
Norethindrone acetate also stimulates mammary tissue growth.
These steady state levels are equal to the level seen in normal premenopausal women during the early follicular phase. Normal steady state levels are attained within 24 hours of patch application. The skin metabolizes estradiol to a small degree. After wearing the patch up to 1 year, estradiol accumulation is not seen. In addition to most tissues, skin and blood hydrolyze norethindrone acetate to norethindrone.