Gynecology & Obstetrics

Trimester In obstetrics, one of these three divisions of three months each during pregnancy in which different phases of fetal development take place. The first trimester is a time of introductory cell isolation. The alternate trimester is a period of rapid-fire growth and development of body systems. A alternate-trimester fetus that's born precociously may be feasible, given the stylish sanitarium care possible. The third trimester makes the final stage of fetal growth, in which systems are completed fat accumulates under the soon-to-be-born baby's skin, and the fetus at last moves into position for birth. This trimester ends with birth.