chapter 29 lecture 6 is labor and partition our tuition is giving birth labor is how it happens labor starts when progesterone's inhibition is overcome by an increase in levels of estrogen so progesterone inhibits uterine contraction so it helps maintain the uterine lining as well as inhibit the eu risk from inter contracting when it's time for birth the placenta stimulates the fetal anterior pituitary to cause a discrete dhea and the placenta converts that to estrogen so estrogen levels rise and the effects of estrogen overcomes those of progesterone and the uterus starts to contract labor begins a decrease in progesterone levels elevated levels of estrogens prostaglandins oxytocin and relaxin are all probably involved in initiation progression of labor uterine contraction forces the fetal head into the cervix and this causes oxytocin to be really released because stretch receptors are activated that causes more contraction producing more stretch in the cervix more nerve impulses and this is the a positive feedback loop true labor begins when the uterine contractions happen at regular intervals usually producing pain uh one sign of true labor is localization in pain in the back also dilation cervix and a discharge of blood containing mucus false labor they call it braxton hicks contractions those are that's pain that occurs at irregular intervals but there's no dilation accompanying it the stages of labor include dilation this is usually six to 12 hours you have regular contractions in the uterus the amniotic sac ruptures that's the water breaking and the cervix dilates to about 10 centimeters expulsion can be anywhere from 10 minutes to several hours as the baby moves through the birth canal and then the placental part is the afterbirth takes about 30 minutes and the rest of the placenta is passed the uh one way to ease the placental stage is to and make it occur more quickly is to nurse as soon as the baby's born that helps this placenta to be passed earlier dystocia is difficult labor and that can be from lots of different things the baby can be in an abnormal position birth canal can be too small and in certain cases um it may be necessary to give a cesarean section or c-section and that's a cut through the abdomen and moving the baby that way um it used to be if you got one c-section you always had to have c-sections but that's not the case you can have vaginal delivery after multiple c-sections so dystocia can be difficult it's difficult labor it can be due to fetal position or size breech presentation is when a baby instead of head first its butt is first or its feet are first and then the c-section is a horizontal incision through the lower abdomen and the uterus the um fetal adrenal medulla secretes high levels of epinephrine norepinephrine that give the fetus protection during the stresses of the birth process after delivery of the baby and placenta there's a period of time it's called the cure perium which is about six weeks after delivery and during this stage the reproductive organs maternal physiology go back to the pre-pregnancy state the uterus shrinks it undergoes involution and there's uterine discharge called lochia of blood and serous fluid for about two to four weeks after delivery the goals for lex lecture says sex are to differentiate between labor and poor tuition how did true labor and false labor differ what are some of the signs of labor listen and describe the three stages of labor define dystocia brief presentation cure perium involution locia and c-section