Labor and Delivery Flashcards
Prostaglandins E and F role in labor
strongly contract uterine smooth muscle and promote oxytocin-induced contractions
inhibitors of prostaglandins prolong gestation …
NSAIDs and Cox-2 inhibitors
Oxytocin involved in maintenance of labor - not initiation
:)
Estrogens effect on myomerium
increases the number of oxytocin receptors
Stage 1 of labor
cervical effacement and dilation
dependent on prostaglandins
Stage 2 of labor
Descent of the presenting party and delivery of fetus
Contractions stimulated by prostaglandins and oxytocin
Stage 3 of labor
Separation and delivery of the placenta
Oxytocin promotes hemostasis by continued contraction of uterus
Uterine smooth muscle relaxation via
B2 adrenergic receptor stimulation
Misoprostol (Cytotec) Use
Oxytocic agent
Induces uterine contractions PO
Vaginal gel stimulates cervical ripening
Oxytocin (Pitocin) Use
Produces uterine and mammary ductal contractions
No effect on cervical dilation but most commonly used for labor induction after cervical ripening
used also for postpartum hemorrhage
Tocolytic therapy goal
to delay delivery long enough to reduce prematurity symptoms in baby
Nifedipine for tocolytic use
Calcium channel blocker
relaxes uterine smooth muscle
Concern that falling BP of mom will effect baby
Terbutaline for tocolytic use
B2-adrenergic agonist - smooth muscle relaxer
Suppresses contractions and treats pre-mature labor
Not effective is cervix is dilated and/or ROM
Terbutaline for tocolytic use concerns
Increased HR, palpitations, hypokalemia, hyperglycemia, hypotension, pulmonary edema
Magnesium Sulfate for tocolytic use
Depress smooth muscle contractions by blocking calcium action.
Not proven to prevent premature birth
Indomethacin for tocolytic use
Prostaglandin synthesis inhibitor - very potent and widely used NSAID
Remember: ductus arteriosis patency dependent on prostaglandins
Can cause pulmonary hypertension in fetus and postnatally
Acetaminophen is safest NSAID for use during pregnancy
:)
Mifepristone use in medical abortion
Progesterone derivative
Competitively antagonizes progesterone receptors –> causes decidual breakdown in early pregnancy
Used orally up to 9 weeks of pregnancy
Must be followed by a prostaglandin (misoprostol)
Methotrexate use in medical abortion
Folic acid antagonist that disrupts rapidly growing tissues
NOT FDA approved … must be followed by a misoprostol
