quality:corruption, information:highlighting, linguistic:translation, linguistic:voice_change
Function

The primary reproductive function of the human uterus is to prepare for the implantation of a zygote, a fertilized ovum, and maintenance of pregnancy if implantation occurs. Traveling along the fallopian tube on its way to the uterine cavity, the zygote divides mitotically to become a blastocyst, which ultimately attaches to the uterine wall and implants into the endometrium. The placenta later develops to nourish the embryo, which grows through embryonic and fetal development until childbirth. During this process, the uterus grows to accommodate the growing fetus. When normal labor begins, the uterus forcefully contracts as the cervix dilates, which results in delivery of the infant.

In the absence of pregnancy, menstruation occurs. The withdrawal of female sex hormones, estrogen and progesterone, which occurs in the absence of fertilization, triggers the shedding of the functional layer of the endometrium. This layer is broken down, shed, and restored in anticipation of the next menstrual cycle. The average bleeding duration during menses is 5-7 days after which the menstrual cycle begins again.