Chapter 20

1. Chapter 20 Maternal Physiologic Changes

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. Breasts • Breastfeeding 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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