Postpartum Physiologic Changes and Nursing Care

The postpartum period, also known as puerperium, is the first six weeks after delivery. Physiological and anatomical changes that occur during the postpartum period include the reversal of changes that occurred during pregnancy.

Now, immediately after delivery, patients usually lose 4.5 to 5.8 kilograms, or 10 to 13 pounds, which includes the weight of the fetus, amniotic fluid, blood, and placenta. Weight loss continues over the next several months due to normalization of blood volume and increased caloric expenditure from milk production.

Okay, let’s now focus on reproductive changes, starting with the uterus. After delivery, the uterus begins to return to its nonpregnant size and position, a process called uterine involution. As soon as the placenta is delivered, uterine muscle fibers constrict around uterine blood vessels to control bleeding. Then, intermittent uterine contractions, referred to as afterpains, continue to further aid uterine involution. The progress of involution can be monitored by palpating the top part of the uterus, called the fundus. At about 12 hours after delivery, the fundus can be palpated at 1 cm above the umbilicus. After that, it normally descends about 1 centimeter, or 1 fingerbreadth, per day, until it reaches the pelvic cavity by the 14th day.

Next, let’s look at the vaginal discharge that occurs after birth, called lochia. The three types of lochia include lochia rubra, lochia serosa, and lochia alba. Lochia rubra refers to the dark red vaginal discharge that’s present for the first 3 days. It consists of blood, small blood clots, decidua, and mucus. As the bleeding reduces, the volume of vaginal discharge reduces, and lochia rubra transforms into lochia serosa. Lochia serosa is a thin, pinkish-brown vaginal discharge that lasts until the 10th day after delivery. It consists of white blood cells, serous exudate, and cervical mucus. As time passes, lochia serosa transforms into lochia alba, which is a yellowish-white discharge that typically lasts until the 14th day after delivery but can persist up to 6 weeks. Lochia alba is rich in epithelial cells, white blood cells, fat, and bacteria.

Now, as the baby descends through the cervix and vagina, trauma can occur, resulting in bruises, lacerations, edema, which resolve over days to weeks.  

By the end of the first week, the external cervical os, or opening, narrows to less than 1 centimeter and appears as a transverse slit. The vaginal wall loses its folds and ridges called vaginal rugae, but they start to reappear 3 to 4 weeks after delivery. At 6 weeks after delivery, the vagina reaches a near pre-pregnant state.

Okay, let’s move on to cardiovascular changes. After delivery, the blood that used to supply the uterus and placenta returns to systemic circulation, causing a transient increase in cardiac output that eventually returns to the pre-labor values within one hour after delivery. The increased plasma volume also lowers the hematocrit, which will return to normal by 6 weeks as the fluid is lost through diuresis, or fluid loss through urine; and through diaphoresis, or sweating.

The white blood cell count increases up to 30,000 cells per mm3 during the first 24 hours. Usually, it takes around one week for the white blood cell count to normalize. Clotting factors that are necessary for coagulation also increase during pregnancy, and continue to be elevated during the postpartum period, which can increase the risk of thrombus formation. It takes 4 to 6 weeks before these factors return to normal, pre-pregnancy values.