PB#107: Induction of Labor Flashcards
Physiologic goal of cervical ripening
Facilitate process of cervical softening/thinning/dilating
Clinical goals of cervical ripening (2)
Reduction in rate of failed IOL, reduction in IOL-to-delivery time
Observed histologic changes during cervical ripening (4)
Collagen breakdown/rearrangement, changes in glycosaminoglycans, increased cytokine production, WBC infiltration
Bishop score signifying unfavorable cervix
6 or less
Bishop score signifying favorable cervix
8 or more
What a “favorable” cervix indicates
Probability of vaginal delivery after IOL is similar to spontaneous labor
Bishop score points for dilation
Closed = 0; 1-cm = 1; 3-4cm = 2, 5-6cm = 3
Bishop score points for position
Post = 0; mid = 1; ant = 2
Bishop score points for effacement
0-30% = 0; 40-50% = 1; 60-70% = 2; 80+% = 3
Bishop score points for station
-3 = 0; -2 = 1; -1–0 = 2; +1 or more = 3
Bishop score points for consistency
Firm = 0; med = 1; soft = 2
General categories for cervical ripening methods (3)
Mechanical dilators, synthetic PGE1, synthetic PGE2
Mechanical cervical ripening options (5)
Hygroscopic dilators, osmotic dilators (Laminaria japonicum), Foley catheters, double balloon devices, EASI balloon
Typical size and inflation volume of cervical Foley balloon
14-26F, 30-80mL
Routes of administration of miso (3); incremental dosages of miso
Vaginal, PO, sublingual; 25mcg increments
Is intrapartum miso exposure associated w/ long-term adverse fetal consequences?
No (in absence of fetal distress)
Available formulations and dosages of PGE2 (2)
2.5mL syringe containing 0.5mg dinoprostone gel, 10mg dinoprostone vaginal insert
Which formulation of PGE2 releases prostaglandins at a slower rate?
Insert (0.3mg/h) over gel
Effect of vaginal prostaglandins for cervical ripening compared to placebo or pit alone on time to delivery; effect on C/S rate; effect on tachysystole
Increase likelihood of delivery within 24h; do not reduce C/S rate; increase risk of tachysystole w/ associated FHR changes
Time from pit onset to uterine response; time of pit onset to steady level in plasma
3-5 mins; 40 mins
Changes in response to pit by gestational age
Gradual increase from 20-30wga, followed by plateau from 34wga until term, then further increase in sensitivity
Predictors for successful response to pit IOL (4)
Lower BMI, greater cervical dilation, higher parity, greater EGA
Cytokines increases associated w/ membrane stripping (2)
Increase in phospholipase A2 activity, increase in PGF2alpha levels
Clinical benefits of membrane stripping (2)
Increases likelihood of spontaneous labor within 48h, reduces incidence of IOL w/ other methods