Limited information on the use of estradiol during breastfeeding indicates that the route of administration and dosage form have influences on the amount transferred into breastmilk. Vaginal administration results in measurable amounts in milk, but transdermal patches do not. Maternal doses of up to 200 mcg daily transdermally do not increase estradiol or estriol in breastfed infants or cause any adverse effects in breastfed infants. Vaginal administration results in unpredictable peak times for estradiol in breastmilk, so timing of the dose with respect to breastfeeding is probably not useful. Milk estradiol levels have not been studied after use of the estradiol gel, but maternal blood levels only increase slightly in a dose-dependent manner. Estrogens can decrease the milk supply, especially if started before the milk supply is well established at about 6 weeks postpartum. The decrease can happen over the first few days of estrogen exposure.[1] A case report of inadequate milk production and inadequate infant weight gain was possibly caused by transdermal estradiol initiated on the first day postpartum, but 2 small studies found no such effect when the drug was initiated after lactation was well established.
关于母乳喂养期间使用雌二醇的信息有限，表明给药途径和剂型会影响进入母乳中的量。经阴道给药会导致母乳中出现可测量的量，但经皮贴片则不会。母亲每天经皮给予高达200微克的剂量不会增加母乳喂养婴儿的雌二醇或雌三醇水平，也不会对母乳喂养婴儿造成任何不良影响。经阴道给药会导致母乳中雌二醇的峰值时间不可预测，因此根据母乳喂养时间来安排给药时间可能没有用。使用雌二醇凝胶后尚未研究母乳中的雌二醇水平，但母亲的血液水平仅以剂量依赖的方式略有增加。雌激素会减少乳汁分泌，尤其是在产后约6周乳汁分泌尚未充分建立之前开始使用时。这种减少可能在接触雌激素的头几天内发生。[1] 一例产后第一天开始使用经皮雌二醇导致乳汁分泌不足和婴儿体重增加不足的病例报告，但两项小型研究发现，在泌乳充分建立后开始使用该药物时没有这种影响。
