Maternal Physiologic Changes



Maternal Physiologic Changes


Kitty Cashion



Learning Objectives



• Describe the anatomic and physiologic changes that occur during the postpartum period.


• Identify characteristics of uterine involution and lochial flow, and describe ways to measure them.


• List expected values for vital signs, deviations from normal findings, and probable causes of the deviations.



Key Terms and Definitions














Web Resources


Additional related content can be found on the companion website at image


http://evolve.elsevier.com/Lowdermilk/Maternity/



T he postpartum period is the interval between the birth of the newborn and the return of the reproductive organs to their normal nonpregnant state. This period is sometimes called the puerperium, or fourth trimester of pregnancy. Although the puerperium has traditionally been considered as lasting 6 weeks, this time frame varies among women. The distinct physiologic changes that occur as the processes of pregnancy are reversed are normal. To provide care during the recovery period that is beneficial to the mother, her infant, and her family, the nurse must synthesize knowledge of maternal anatomy and physiology of the recovery period, the newborn’s physical and behavioral characteristics, infant care activities, and family response to the birth of the infant. This chapter focuses on anatomic and physiologic changes that occur in the mother during the postpartum period.



Reproductive System and Associated Structures image


Uterus


Involution process


The return of the uterus to a nonpregnant state after birth is known as involution. This process begins immediately after expulsion of the placenta with contraction of the uterine smooth muscle.


At the end of the third stage of labor the uterus is in the midline, approximately 2 cm below the level of the umbilicus, with the fundus resting on the sacral promontory. At this time the uterus weighs approximately 1000 g.


Within 12 hours the fundus rises to the level of the umbilicus, or slightly above or below (Fig. 13-1). Thereafter the fundus descends approximately 1 cm every day. By 1 week after birth the fundus is located 4 to 5 fingerbreadths below the umbilicus. The uterus should not be palpable abdominally after 2 weeks and should have returned to its nonpregnant location by 6 weeks after birth (Blackburn, 2007).


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Fig. 13-1 Assessment of involution of uterus after childbirth. A, Normal progress, days 1 through 9. B, Size and position of uterus 2 hours after childbirth. C, Two days after childbirth. D, Four days after childbirth. (B, C, D, Courtesy Marjorie Pyle, RNC, Lifecircle, Costa Mesa, CA.)


image Spanish Guidelines: Postpartum Physical Examination


The uterus, which at full term weighs approximately 11 times its prepregnancy weight, involutes to approximately 500 g by 1 week after birth and to 350 g by 2 weeks after birth. At 6 weeks, it weighs 60 to 80 g (see Fig. 13-1).


Increased estrogen and progesterone levels are responsible for stimulating the massive growth of the uterus during pregnancy. Prenatal uterine growth results from both hyperplasia, an increase in the number of muscle cells, and from hypertrophy, an enlargement of the existing cells. Postpartally, the decrease in these hormones causes autolysis, the self-destruction of excess hypertrophied tissue. The additional cells laid down during pregnancy remain, however, and account for the slight increase in uterine size after each pregnancy.


Subinvolution is the failure of the uterus to return to a nonpregnant state. The most common causes of subinvolution are retained placental fragments and infection (see Chapter 23).



Contractions


Postpartum hemostasis is achieved primarily by compression of intramyometrial blood vessels as the uterine muscle contracts rather than by platelet aggregation and clot formation. The hormone oxytocin, released from the pituitary gland, strengthens and coordinates these uterine contractions, which compress blood vessels and promote hemostasis. During the first 1 to 2 postpartum hours, uterine contractions may decrease in intensity and become uncoordinated. Because the uterus must remain firm and well contracted, exogenous oxytocin (Pitocin) is usually administered intravenously or intramuscularly immediately after expulsion of the placenta. Women who plan to breastfeed should also be encouraged to put the baby to the breast immediately after birth because suckling stimulates oxytocin release.





Lochia


Post-childbirth uterine discharge, commonly called lochia, is initially bright red (lochia rubra) and may contain small clots. For the first 2 hours after birth the amount of uterine discharge should be approximately that of a heavy menstrual period. After that time the lochial flow should steadily decrease.


Lochia rubra consists mainly of blood and decidual and trophoblastic debris. The flow pales, becoming pink or brown (lochia serosa) after 3 to 4 days. Lochia serosa consists of old blood, serum, leukocytes, and tissue debris. The median duration for lochia serosa discharge is 22 to 27 days (Katz, 2007). In most women, approximately 10 days after childbirth the drainage becomes yellow to white (lochia alba). Lochia alba consists primarily of leukocytes and decidual cells but also contains epithelial cells, mucus, serum, and bacteria. Lochia alba may last until 6 weeks after birth (Blackburn, 2007).



Critical Thinking/Clinical Decision Making


Assessment of Postpartum Bleeding


You are the nurse assigned to care for Margarita, a G9 P9 who gave birth vaginally 1 hour ago to twins. Twin A weighed 7 pounds, 4 ounces, and Twin B weighed 6 pounds, 12 ounces. Margarita did not have an episiotomy and sustained no lacerations requiring repair. You are at the nurse’s station when Margarita calls and asks for her nurse to “come quick!” When you arrive in her room, you find Margarita lying in a puddle of blood. The disposable pad underneath her, as well as Margarita’s perineal pad, are completely soaked with blood.



If the woman receives an oxytocic medication, the flow of lochia is often scant until the effects of the medication wear off. The amount of lochia is typically smaller after cesarean births. Flow of lochia usually increases with ambulation and breastfeeding. Lochia tends to pool in the vagina when the woman is lying in bed; on standing the woman may experience a gush of blood. This gush should not be confused with hemorrhage.


Persistence of lochia rubra early in the postpartum period suggests continued bleeding as a result of retained fragments of the placenta or membranes. Recurrence of bleeding approximately 7 to 14 days after birth is from the healing placental site. Approximately 10% to 15% of women will still be experiencing normal lochia serosa discharge at the 6-week postpartum examination (Katz, 2007). In the majority of women, however, a continued flow of lochia serosa or lochia alba by 3 to 4 weeks after birth may indicate endometritis, particularly if fever, pain, or abdominal tenderness is associated with the discharge. Lochia should smell similar to normal menstrual flow; an offensive odor usually indicates infection.


Not all postpartal vaginal bleeding is lochia; vaginal bleeding after birth may be a result of unrepaired vaginal or cervical lacerations. Table 13-1 distinguishes between lochial and nonlochial bleeding.


Related posts:

  1. Labor and Birth at Risk
  2. 21st Century Maternity Nursing: Culturally Competent, Family and Community Focused
  3. Postpartum Complications
  4. Assessment and Care of the Newborn and Family

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Oct 8, 2016 | Posted by in NURSING | Comments Off on Maternal Physiologic Changes

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