Zika Continues To Alarm: Study Finds That Brain Damage Can Still Occur Even In The Third Trimester For pregnant women, the first trimester is the hardest part–at least in terms of worrying about things like miscarriage, and normal fetal development. Some diseases, like rubella, which can result in traumatic results for fetuses if contracted in the first trimester are considerably less so if contracted later in the pregnancy.… Read the rest