Labor and delivery Flashcards
What vitamin (?) plays a role in controlling uterine muscle contraction
Calcium!
Ca flows into cytoplasm w/ transporters through channels
Ca-ATPase and Na/Ca exchangers maintain IC calcium homeostasis
Uterine contractions depend on
formation of contractile protein actomysin and hydrolysis of ATP to produce motion
What has an inhibitory effect on uterine contraction
ATP sensitive potassium channel stimulation AKA open K channels
(hyperpolarization of myometrial cells)
Why do we have uterine contractions in labor
Promote cervical ripening (soft, thin cervix)
Control post-partum hemorrhage (MCC of perinatal maternal death)
Terminate pregnancy
What drugs promote uterine contractions
Oxytocin: induce labor (contractions), promote cervical ripening
PGE2: promote cervical ripening and contractions
Carboprost: control postpartum hemorrhage
Mifepristone: terminate pregnancy
Methylergonovine: control postpartum hemorrhage
How does oxytocin work
opens non-specific cation channels= open L type Ca channels= release of Ca from sarcoplasmic reticulum and decrease Ca efflux
How do you dose oxytocin
Start low and gradually increase to desired effect
Excessive uterine contractions can lead to
Uterine rupture
Fetal distress
How do you use the PGE2 (dinoprostone) gel and how does it work (prepidil)
Place in cervical canal= cervical ripening
promotes uterine contractions
*Place in cervix when you plan on inducing labor w/ oxytocin in 1-2 days
How do you place PGE2 (dinoprostone) vaginal insert (cervidil)
insert into posterior fornix of vagina
remove just before delivery
Vaginal suppository of PGE2 can be used to
Terminate pregnancy 2/2 missed abortion, IU fetal death, and benign hydatiform mole); it is basically a stronger version (20mg) of Cervidil (10mg) and Prostadil (1/2 mg)
Can be used from week 12-20 of gestation
ADE for all PGE2 include
nausea
vomiting
+/- fever
HTN and hypotension have been reported
How does Carboprost work
Methylated analogue of PGF2a given IM; causes strong uterine contractions that is good for postpartum hemorrhage
Can induce uterine emptying at 13-20 weeks gestation, but NOT for elective abortions with a viable infant
ADE of carboprost include
Bronchospasm (DO NOT use in asthma!) Hypertension Diarrhea Vomiting "Choking"
How does Mifepristone work
Progesterone antagonist used to terminate pregnancy through 49 day of gestation
-Also used off label for cushing’s