the myometrium stretches (the smooth muscle cells expand in both size and number) during pregnancy to allow for the uterus to become several times its non-gravid size, and contracts in a coordinated fashion, via a positive feedback effect on the "ferguson reflex", during the process of labor. after delivery the myometrium contracts to expel the placenta, and crisscrossing fibres of middle layer compress the blood vessels to minimize blood loss. a positive benefit to early breastfeeding is a stimulation of this reflex to reduce further blood loss and facilitate a swift return to prepregnancy uterine and abdominal muscle tone.