Chapter 183 Routine Prenatal Care: Third Trimester
THE CHALLENGE
Scope of the Problem: It is during the third trimester that the uterus and fetus prepare for labor and delivery. It is also during this phase of pregnancy that complications such as pre-eclampsia, bleeding, complications of diabetes or hypertension, abnormalities of growth or amniotic fluid, and preterm labor may arise.
TACTICS
Relevant Pathophysiology: During the third trimester of gestation, the dramatic growth of the fetus continues as it gains its final birthweight and its organs prepare for full function as an autonomous individual. Maternal blood volume almost doubles, and cardiac output reaches its maximum. By the 29th week, the fetus has 300 bones, although many of them will fuse after birth, leaving the adult total of 206. The fetal presenting part begins to descend into the maternal pelvis in the last month of pregnancy, resulting in a decline in fundal height, improved respiratory and gastric function, and greater pelvic pressure and discomfort. Late in this trimester, changes in the cervix begin the preparations for dilation and effacement during labor and delivery.
