Cluster 39: excluded pregnant women study patients men breastfeeding participating studied trial Cluster 534: breastfeeding discontinued excluded pregnant women participants mother lactating study treated Cluster 977: mother discontinued breastfeeding agent study excluded pregnant women treated discontinuation Cluster 1572: milk stored future mother breastfeeding note pregnant breast treated use Cluster 2074: mother breastfeeding discontinued pregnant treated women excluded study agents apply Cluster 2104: breastfeeding women excluded pregnant discontinued study prior nursing avoided treatment Cluster 2321: nursing pregnancy infant mother donor patients females active women excluded