Refractory period (sex) after orgasm in which further sexual stimulation does not produce excitement. While the refractory period varies widely among individuals, ranging from minutes to days, most men cannot achieve or maintain an erection during this time, and many perceive a psychological feeling of satisfaction and are temporarily uninterested in further sexual activity; the penis may be hypersensitive and further sexual stimulation may feel painful during this time frame. An increased infusion of the hormone oxytocin during ejaculation is believed to be chiefly responsible for the male refractory period, and the amount by which oxytocin is increased may affect the length of
Human milk microbiome in mature milk. Taxonomic composition of human milk also varies across the lactation period, initially dominated by "Weisella, Leuconostoc, Staphylococcus, Streptococcus," and "Lactococcus" species, and later composed primarily of "Veillonella, Prevotella, Leptotrichia, Lactobacillus, Streptococcus, Bifidobacterium," and "Enterococcus" Human milk oligosaccharides, a primary component of human milk, are prebiotics which have been shown to promote growth of beneficial "Bifidobacterium" and "Bacteroides" species. Mode of delivery may influence composition of the human milk microbiome, vaginal births being associated with high taxonomic diversity and high prevalence of "Bifidobacterium" and "Lactobacillus," and the opposite trend being seen with Cesarean births, however, no relationship between