22.4 Human Pregnancy, Birth and Lactation

Question 1

Colostrum

Answer 1

Colostrum is the first form of milk produced by the mammary glands during late pregnancy and in the first few days after childbirth. It is thick, yellowish, and rich in antibodies, protein, and nutrients. Colostrum provides essential immune protection and nourishment to the newborn before regular breast milk production begins.

Question 2

oxytocin

Answer 2

Oxytocin is a hormone produced by the hypothalamus and released by the posterior pituitary gland. It plays a key role in labor by stimulating uterine contractions during childbirth and in milk ejection during breastfeeding. Oxytocin is also involved in promoting bonding and emotional connections.

Question 3

parturition

Answer 3

Parturition is the process of giving birth or childbirth. It involves three stages:

Dilation: The cervix dilates and effaces to prepare for delivery.
Expulsion: The baby is delivered.
Placental: The placenta is expelled from the uterus after the baby is born.

Question 4

prolactin

Answer 4

Prolactin is a hormone produced by the anterior pituitary gland. It is primarily responsible for stimulating the production of milk in the mammary glands after childbirth. Prolactin levels increase during pregnancy and remain elevated during breastfeeding to support milk production.

Question 5

prostaglandins

Answer 5

Prostaglandins are hormone-like substances produced in various tissues throughout the body. They play a key role in processes such as inflammation, pain regulation, blood flow, and uterine contractions during labor. In pregnancy, prostaglandins help initiate labor by softening and dilating the cervix.

Question 6

relaxin

Answer 6

Relaxin is a hormone produced by the ovaries and placenta during pregnancy. It helps relax the ligaments in the pelvis and softens the cervix in preparation for childbirth. Relaxin also helps to increase blood flow to the uterus and supports the changes needed for labor and delivery.

Question 7

Stage 1

Answer 7

cervix dilates
cervical canal slowly disappears as the lower part of the uterus is pulled towards the baby’s head. baby’s head acts like a wedge to assist in cervical dilation during subsequent contractions. amniotic membrane ruptures and the mucus plug from the cervix is expelled. stage ends when the cervix is fully dilated

Question 8

Stage 2

Answer 8

baby emerges
contractions every 1-2 minutes lasting about a minute. the baby’s head descends into the vagina, and the woman has an increased desire to push. the babys head reaches the exterior, then turns so that the back of the head is uppermost. an incision called an episiotomy may be needed. as soon as the head is delivered, the babys shoulders rotate so that the baby faces left or right. the rest of baby’s body follows easily

Question 9

Stage 3

Answer 9

expelling afterbirth
bout 15 minutes after delivery, uterine contractions shrink the uterus to dislodge the placenta. the placenta is expelled into the vagina and is delivered.