Maternal Physiologic Changes Chapter 20 Maternal Physiologic Changes

Maternal Physiologic Changes Postpartum period is interval between birth and return of reproductive organs to their nonpregnant state Referred to as puerperium or fourth stage of pregnancy Traditionally lasts 6 weeks, although this varies among women

Reproductive System and Associated Structures Uterus Involution: return of uterus to nonpregnant state following birth Progresses rapidly Fundus descends 1 to 2 cm every 24 hours 2 weeks after childbirth uterus lies in true pelvis Subinvolution: failure of uterus to return to nonpregnant state Common causes are retained placental fragments and infection

Reproductive System and Associated Structures—cont’d Uterus Contractions Hemostasis achieved by compression of intramyometrial blood vessels as uterine muscle contracts Hormone oxytocin, released from pituitary gland, strengthens and coordinates uterine contractions

Reproductive System and Associated Structures—cont’d Uterus Afterpains Placental site Lochia: postbirth uterine discharge Lochia rubra Blood and decidual and trophoblastic debris Duration of 3 to 4 days

Reproductive System and Associated Structures—cont’d Uterus Lochia: postbirth uterine discharge Lochia serosa Old blood, serum, leukocytes, and debris Duration of 22 to 27 days Lochia alba Leukocytes, decidua, epithelial cells, mucus, serum, and bacteria Continues 2 to 6 weeks after birth

Reproductive System and Associated Structures—cont’d Cervix Soft immediately after birth Within 2 to 3 postpartum days it has shortened, become firm, and regained form Ectocervix appears bruised and has small lacerations—optimal conditions to develop infections Cervical os, dilated to 10 cm during labor, closes gradually

Reproductive System and Associated Structures—cont’d Vagina and perineum Estrogen deprivation responsible for thinness of vaginal mucosa and absence of rugae Vagina gradually returns to prepregnancy size by 6 to 10 weeks after childbirth Thickening of vaginal mucosa occurs with return of ovarian function Dryness and coital discomfort, dyspareunia, may persist until return of ovarian function

Reproductive System and Associated Structures—cont’d Vagina and perineum Introitus is erythematous and edematous Episiotomies heal within 2 to 3 weeks Hemorrhoids and anal varicosities are common and decrease within 6 weeks of childbirth

Reproductive System and Associated Structures—cont’d Vagina and perineum Pelvic muscular support Supportive tissues of pelvic floor torn or stretched during childbirth Require up to 6 months to regain tone Kegel exercises encourage healing

Abdomen Abdomen During first 2 weeks abdominal wall remains relaxed Woman has still-pregnant appearance Return to prepregnancy state takes 6 weeks Depends on previous tone, proper exercise, and amount of adipose tissue

Endocrine System Placental hormones Expulsion of placenta results in dramatic decreases of placental-produced hormones Decreases in chorionic somatomammotropin (hCS), estrogens, cortisol, and placental enzyme insulinase reverse effects of pregnancy Estrogen and progesterone levels drop markedly

Endocrine System—cont’d Pituitary hormones and ovarian function Lactating and nonlactating women differ in timing of first ovulation and menstruation 70% of nonbreastfeeding mothers menstruate within first 12 weeks In breastfeeding women return of ovulation depends on breastfeeding patterns May ovulate before first menstrual cycle

Urinary System Urine components Postpartal diuresis Within 12 hours women begin to diurese Profuse diaphoresis often occurs at night for first 2 to 3 days Urethra and bladder Excessive bleeding can occur because of displacement of the uterus if bladder is full

Breasts Breastfeeding mothers Nonbreastfeeding mothers Before lactation a yellowish fluid, colostrum, can be expressed from nipples Tenderness may persist for 48 hours after start of lactation Nonbreastfeeding mothers Engorgement resolves spontaneously, and discomfort decreases within 24 to 36 hours Breast binder or tight bra, ice packs, or mild analgesics may be used to relieve discomfort

Cardiovascular System Blood volume Blood volume increase eliminated within first 2 weeks after birth, with return to nonpregnancy values by 6 months after delivery Readjustments in maternal vasculature after childbirth dramatic and rapid

Integumentary System Chloasma of pregnancy usually disappears at end of pregnancy Hyperpigmentation of areolae and linea nigra may not regress completely after childbirth Some women will have permanent darker pigmentation of those areas Stretch marks on breasts, abdomen, and thighs may fade but not disappear

Immune System No significant changes in maternal immune system occur during postpartum period Mother’s need for rubella vaccination or for Rho (D) immune globulin for prevention of Rh isoimmunization is determined

Key Points Uterus involutes rapidly after birth, returning to true pelvis within 2 weeks Rapid decrease in estrogen and progesterone levels after expulsion of placenta responsible for triggering many anatomic and physiologic changes in puerperium

Key Points—cont’d Assessment of lochia and fundal height is essential to monitor progress of normal involution and identify potential problems Return of ovulation and menses is determined in part by whether woman breastfeeds infant Few alterations in vital signs are seen after birth under normal circumstances

Key Points—cont’d Hypercoagulability, vessel damage, and immobility predispose the woman to thromboembolism Marked diuresis, decreased bladder sensitivity, and overdistention of the bladder can lead to problems with urinary elimination Pregnancy-induced hypervolemia allows women to tolerate considerable blood loss at birth