Parturition

Dr. Sadaf Mumtaz15/02/11

• Dilatation of cervix– Relaxin (corpus luteum & placenta)

• Softens cervix• Relaxes birth canal by loosening the connective tissue

between pelvic bone– Prostaglandins

• Contraction of Uterine myometrium– Role of high estrogen levels/ Increases ratio of estrogen to

progesterone• Gap Junctions• Increased number of oxytocin receptors• Cervical ripening local prostaglandins cervical

enzymes collagen fibers– Role of oxytocin

• Increased receptors• Rate of secretion at the time of labour

– Effect of fetal hormones• Oxytocin• Cortisol• Prostaglandins

Role of Inflammation

• Nuclear factor-ĸβ– IL-8– Prostaglandins

• Increase sensitivity of uterus to contraction

inducing chemical messengers

• Help soften the cervix

Factors leading to activation of NF-ĸβ

• Stretching of uterine cervix

• Presence of pulmonary surfactant protein SP-A in the amniotic fluid

• SP-A promotes migration of fetal macrophages to uterus which produce IL-1β that activates NF-ĸβ

Mechanical Factors

• Stretch of the uterine musculature– Fetal movements– Twins

• Stretch or irritation of cervix

BRAXTON-HICKS CONTRACTIONS

Mechanism of Parturition

• Cervical dilatation– 24 hrs

• Delivery of the baby– 30-90mins

• Delivery of the placenta– 15-30mins– 350 ml of blood lost– SMC – Prostaglandins

Involution of uterus

Lactation

• Role of estrogen and progesterone

• Role of hCS

• Colostrum (Fluid secreted during the last few days before and the first few days after parturition)

• Role of growth hormone, cortisol, parathyroid hormone & insulin

Changes in rates of secretion of estrogens, progesterone and prolactin

Advantages of breast feeding

• Immune cells such as B and T lymphocytes, macrophages, neutrophills,

• Secretory IgA --- Ecoli• Mucus• Lactoferrin – decreases availability of iron from

bacteria• Bifidus Factor---promotes growth of non-

pathogenic micro-organism lactobacillus bifidus. Growth of this bacteria helps crowd out potentially harmful bacteria

Advantages of breast feeding for the mother

• Oxytocin released triggered by nursing hastens uterine involution

• Subsequent effect of increased prolactin– Inhibit GnRH and thereby stopping release of

LH and FSH

Assignments

• Preeclampsia and Eclampsia– Effects on the mother, fetus and placenta– Treatment

Wednesday 23rd of february

Thankyou