Parturition and Lactation (2020) PDF

## Parturition Stimulated by hormonal changes, some of which originate in the fetus to indicate gestation is complete. - Fetal cortisol increases, and the fetus pushes on the cervix. - Stimulation of the cervix causes prostaglandin secretion (muscle contraction), which in turn stimulates oxytocin...

## Parturition Stimulated by hormonal changes, some of which originate in the fetus to indicate gestation is complete. - Fetal cortisol increases, and the fetus pushes on the cervix. - Stimulation of the cervix causes prostaglandin secretion (muscle contraction), which in turn stimulates oxytocin release from the posterior pituitary. - Oxytocin also produces muscle contraction (myometrium), which pushes the baby onto the cervix = positive feedback. - This increases frequency and intensity of contractions. **Hormonal Changes at Parturition** - Fetal cortisol - Prostaglandins - Oxytocin - Estrogen - Progesterone During gestation (in months) - At parturition, oxytocin, estrogen, prostaglandins, and cortisol are up. - Progesterone is down. ## Lactation Production of milk to support baby. Mammary glands produce milk. - _20 lobes of exocrine tissue_ - _and ducts lined with smooth muscle_ - Estrogen activates the prolactin pathway - Prolactin stimulates milk production. - Progesterone inhibits prolactin (during pregnancy) First milk is called colostrum - no fat, sugar and proteins After 3-4 days milk is produced - A cow can make 1.5 L of milk daily. - 50g of fat, 100g sugar and 2-3g calcium. - Breast milk also contains antibodies which give baby passive immunity While mothers are lactating... there is no fluctuation in LH, FSH, or progesterone. - No menstrual cycle - Lactational amenorrhea **Flowchart** - Baby wants milk - Crying impulse sends signal to mother - Baby sucks on the breast stimulating the areola - Prolactin increases milk production - Oxytocin released, leading to smooth muscle contractions - More milk released "Infanticide" - Make fertile