Induction Lecture Fmdrl

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Induction Lecture Fmdrl

  1. 1. Getting Things Started… Cervical Ripening and Labor Induction Jennifer Frank MD Fox Valley FMR Program
  2. 2. The best teachers… <ul><li>Are our patients. </li></ul><ul><ul><li>Case 1: 36 yo G2P1 at 39 weeks for social induction. </li></ul></ul><ul><ul><ul><li>VBAC </li></ul></ul></ul><ul><ul><ul><li>Cytotec for cervical ripening </li></ul></ul></ul><ul><ul><li>Case 2: 29 yo G1 at 40 +2 weeks for social induction </li></ul></ul><ul><ul><ul><li>Cytotec for cervical ripening </li></ul></ul></ul>
  3. 3. Take home points (or learning objectives) <ul><li>Cervical ripening, labor induction, and labor augmentation carry risks that are potentially serious to mom and baby and must be weighed by the potential benefit. </li></ul><ul><li>There is good evidence to direct the safe use of cervical ripening agents and agents used for labor induction and labor augmentation. </li></ul><ul><li>There are clinical indications when labor induction (+/- cervical ripening) is appropriate. </li></ul>
  4. 4. Indications for Labor Induction <ul><li>Maternal and fetal indications </li></ul><ul><ul><li>Placental abruption </li></ul></ul><ul><ul><li>Chorioamnionitis </li></ul></ul><ul><ul><li>Fetal demise </li></ul></ul><ul><ul><li>Gestational hypertension, preeclampsia, eclampsia </li></ul></ul><ul><ul><li>Premature ROM </li></ul></ul><ul><ul><li>Postterm pregnancy </li></ul></ul><ul><ul><li>Maternal medical indications </li></ul></ul><ul><ul><li>Fetal compromise (e.g. IUGR) </li></ul></ul>
  5. 5. Indications for Induction <ul><li>Other types of indications </li></ul><ul><ul><li>Risk of rapid labor </li></ul></ul><ul><ul><li>Distance from hospital </li></ul></ul><ul><ul><li>Psychosocial indications </li></ul></ul><ul><li>ACOG Practice Guideline No. 10. Induction of labor. </li></ul>
  6. 6. Contraindications to Labor Induction <ul><li>Vasa previa </li></ul><ul><li>Complete placenta previa </li></ul><ul><li>Transverse fetal lie </li></ul><ul><li>Umbilical cord prolapse </li></ul><ul><li>Previous transfundal uterine surgery </li></ul><ul><li>ACOG Practice Guideline No. 10. Induction of labor. </li></ul>
  7. 7. Additional Contraindications <ul><li>Absolute </li></ul><ul><ul><li>Pelvic structural abnormality </li></ul></ul><ul><ul><li>Active genital herpes infection </li></ul></ul><ul><ul><li>Invasive cervical cancer </li></ul></ul><ul><li>Relative </li></ul><ul><ul><li>Abnormal FHT </li></ul></ul><ul><ul><li>Breech presentation </li></ul></ul><ul><ul><li>Maternal heart disease </li></ul></ul><ul><ul><li>Multifetal pregnancy </li></ul></ul><ul><ul><li>Polyhydramnios </li></ul></ul><ul><ul><li>Presenting part above pelvic inlet </li></ul></ul><ul><ul><li>Severe maternal hypertension </li></ul></ul>Harman JH, Kim A. Current trends in cervical ripening and labor induction. AFP 1999;60:477-84.
  8. 8. Successful Labor Induction <ul><li>Different definitions of success </li></ul><ul><ul><li>Achieve vaginal delivery in specified time (12-24 hours) </li></ul></ul><ul><ul><li>Achieve active labor within a specified time </li></ul></ul><ul><ul><li>Achieve active labor </li></ul></ul>
  9. 9. Factors Predicting Success <ul><li>Cervical status </li></ul><ul><ul><li>Traditional Bishop score > 9 </li></ul></ul><ul><ul><li>Favorable score varies from > 5 to > 8 </li></ul></ul><ul><ul><li>Inverse relationship b/w cervical score and length of latent phase of labor </li></ul></ul><ul><ul><li>Increased risk of cesarean delivery with “unfavorable” cervix (generally < 5) </li></ul></ul><ul><li>Crane JM. Factors predicting labor induction success: A critical analysis 2006; </li></ul><ul><li>Clin Obstet Gynecol 49;573-84. </li></ul>
  10. 10. Maternal Factors <ul><li>Maternal characteristics </li></ul><ul><ul><li>Parity </li></ul></ul><ul><ul><ul><li>Variable evidence for the weight this has on predicting delivery within 24 hours </li></ul></ul></ul><ul><ul><li>Height </li></ul></ul><ul><ul><ul><li>Association between taller women and increased chance of vaginal delivery within 12-24 hours of starting labor induction </li></ul></ul></ul><ul><ul><li>Weight </li></ul></ul><ul><ul><ul><li>Lower weight – more likely to be successful </li></ul></ul></ul><ul><ul><li>Age </li></ul></ul><ul><ul><ul><li>Younger women are more likely to be successful </li></ul></ul></ul>
  11. 11. Fetal Factors <ul><li>Higher birth weights (>3.5 kg) associated with increased risk for failed induction (lower rate of vaginal delivery within 24 hours) </li></ul><ul><li>Increasing gestational age associate with increased likelihood of labor induction success </li></ul>
  12. 12. Fetal maturity <ul><li>Criteria for establishing fetal maturity </li></ul><ul><ul><li>  Fetal heart tones documented for at least 20 weeks by nonelectronic fetoscope or for 30 weeks by Doppler </li></ul></ul><ul><ul><li>At least 36 weeks since a positive HCG (serum or urine) </li></ul></ul><ul><ul><li>At least 39 weeks' gestation based on crown-rump length performed at 6–11 weeks' gestation </li></ul></ul><ul><ul><li>At least 39 weeks' gestation based on ultrasound measurement at 12–20 weeks' gestation </li></ul></ul><ul><li>Sanchez-Ramos L. Induction of labor. Obstet Gynecol Clin North Am - 01-JUN-2005; 32(2): 181-200, viii </li></ul>
  13. 13. Cervical Ripening <ul><li>Softening, effacement, dilation preceding active labor </li></ul><ul><li>Prostaglandins play an unknown role in mediating cervical ripening </li></ul><ul><li>When is it needed? </li></ul><ul><ul><li>“Unripe cervix” based on cervical score (usually < 6 on Bishop score) </li></ul></ul>
  14. 14. Bishop score ___ Soft Med Firm Consistency ___ Anter Mid Post Position +1 to +2 -1 or 0 -2 -3 Station 80 60-70 40-50 0-30 Effacement (%) 5-6 3-4 1-2 0 Dilation 3 2 1 0 Factor
  15. 15. Assessing Cervix <ul><li>TVUS </li></ul><ul><ul><li>More objective </li></ul></ul><ul><ul><li>Not superior to Bishop score in meta-analysis </li></ul></ul><ul><li>Fetal fibronectin </li></ul><ul><ul><li>May bind placenta and membranes to decidua </li></ul></ul><ul><ul><li>Presence associated with preterm birth </li></ul></ul><ul><ul><li>Not superior to Bishop score </li></ul></ul><ul><li>Insulin-like growth factor binding protein-1 </li></ul><ul><ul><li>Synthesized by maternal decidua, may be released with cervical ripening and fetal membrane separating from decidua </li></ul></ul><ul><ul><li>May indicate cervical “ripeness” </li></ul></ul>
  16. 16. Methods of cervical ripening <ul><li>Low dose oxytocin </li></ul><ul><ul><li>< 4 mU/minute </li></ul></ul><ul><li>Dinoprostone (PGE 2 ) </li></ul><ul><ul><li>Intravaginal or intracervical </li></ul></ul><ul><ul><li>FDA approved for cervical ripening </li></ul></ul><ul><ul><li>Pt needs to be recumbent for 30 minutes and should be monitored for 1-4 hours </li></ul></ul><ul><ul><li>Onset of contractions usu. within 1 st hour, peak at 4 hours </li></ul></ul>
  17. 17. Methods of cervical ripening continued <ul><li>Misoprostol: PGE 1 </li></ul><ul><ul><li>Not FDA approved for this indication </li></ul></ul><ul><ul><li>Oral or vaginal administration* </li></ul></ul><ul><ul><li>3x systemic bioavailability of vaginal vs. oral </li></ul></ul><ul><ul><li>As or more effective than other methods </li></ul></ul><ul><ul><li>Increased risk of tachysystole </li></ul></ul><ul><ul><ul><li>Has not equated with worse overall outcomes </li></ul></ul></ul><ul><ul><li>Hyperstimulation occurs in 1-10% of patients </li></ul></ul><ul><ul><li>Cheaper and more convenient </li></ul></ul><ul><ul><li>Recommend informed consent </li></ul></ul>
  18. 18. Nonpharmacologic methods for cervical ripening <ul><li>Stripping or sweeping the membranes </li></ul><ul><ul><li>Causes an increase in prostaglandins </li></ul></ul><ul><ul><li>Insert finger through internal cervical os and move in a circular direction to detach the inferior part of the membranes from the lower uterine segment </li></ul></ul><ul><ul><li>Risks: infection, bleeding, accidental amniotomy, discomfort </li></ul></ul><ul><ul><li>Alone is not effective but may reduce dose of oxytocin needed </li></ul></ul><ul><ul><li>Important note: Strippingmembranes.com is for sale </li></ul></ul>
  19. 19. Nonpharmacologic methods for cervical ripening continued <ul><li>Mechanical dilators – local pressure stimulating release of prostaglandins and dilating cervix </li></ul><ul><ul><li>Hygroscopic (osmotic) dilators </li></ul></ul><ul><ul><li>Balloon devices (Foley bulb) </li></ul></ul><ul><ul><ul><li>Method & materials </li></ul></ul></ul><ul><ul><li>Effective for cervical ripening (compared to misoprostol, PGE 2 ) </li></ul></ul><ul><li>Amniotomy </li></ul><ul><ul><li>Increases production/release of prostaglandins </li></ul></ul><ul><ul><li>Evidence does not support use for labor induction </li></ul></ul>
  20. 20. Alternative methods for cervical ripening <ul><li>Evening primrose oil, Black Haw, Black and blue cohosh, red raspberry leaves </li></ul><ul><ul><li>All have uncertain role </li></ul></ul><ul><li>Castor oil, hot baths, enemas </li></ul><ul><ul><li>No evidence to support use </li></ul></ul><ul><li>Sexual intercourse – stimulation of oxytocin release and prostaglandins </li></ul><ul><ul><li>Uncertain role, but fun to try. </li></ul></ul><ul><li>Breast stimulation </li></ul><ul><ul><li>May be helpful but no good evidence </li></ul></ul><ul><li>Acupuncture/transcutaneous nerve stimulation </li></ul><ul><ul><li>May have benefit, need better studies </li></ul></ul><ul><li>Tenore, JL. Methods for cervical ripening and induction of labor. AFP 2003. </li></ul>
  21. 21. Labor Induction <ul><li>Stimulating uterine contractions to promote delivery prior to the onset of spontaneous active labor </li></ul><ul><li>Rate is > 20% and increasing </li></ul><ul><li>Most common indication is postterm pregnancy </li></ul>
  22. 22. Risks of Labor Induction <ul><li>Operative vaginal delivery </li></ul><ul><li>Cesarean delivery </li></ul><ul><li>Excessive uterine activity with abnormal FHR patterns (uterine hyperstimulation) </li></ul><ul><li>Delivery of preterm infant </li></ul>
  23. 23. Labor Induction - ACOG <ul><li>PGE analogues are effective for both cervical ripening and labor induction (Level A) </li></ul><ul><li>Cytotec at doses of 25 micrograms every 3-6 hours are effective for cervical ripening and labor induction (Level A) </li></ul><ul><li>With term PROM, may induce labor with prostaglandins (Level A) </li></ul><ul><li>Increased complications with doses of cytotec > 50 mcg (Level B) </li></ul><ul><li>Avoid cytotec in VBAC (Level B) </li></ul>
  24. 24. Methods of Labor Induction <ul><li>Oxytocin </li></ul><ul><ul><li>Oxytocin receptors in the uterus increase starting at 32 weeks </li></ul></ul><ul><ul><li>IV administration of solution of 10 Units to 1 Liter of isotonic solution = 10 mU/1mL </li></ul></ul><ul><ul><li>Continuous infusion vs. pulsed dosing </li></ul></ul><ul><ul><ul><li>Continuous usually start at 0.5 to 2.5 mU/min increased by same increment every 15-60 minutes </li></ul></ul></ul><ul><ul><ul><li>Effect within 3-5 minutes, steady state by 15-30 min. </li></ul></ul></ul><ul><ul><ul><li>No clearly superior regimen – great variability in response </li></ul></ul></ul>
  25. 25. Methods of Labor Induction <ul><li>PGE 1 </li></ul><ul><li>PGE 2 </li></ul><ul><li>Oxytocin </li></ul>
  26. 26. Oxytocin continued <ul><li>Oxytocin is good… </li></ul><ul><ul><li>It is potent </li></ul></ul><ul><ul><li>May titrate </li></ul></ul><ul><ul><li>Short half-life </li></ul></ul><ul><ul><li>Well tolerated </li></ul></ul>
  27. 27. Oxytocin for labor induction <ul><li>Low-dose </li></ul><ul><ul><li>Start at 0.5-2 mU/min </li></ul></ul><ul><ul><li>Increase by 1-2 mU/min every 15-40 minutes </li></ul></ul><ul><li>High-dose </li></ul><ul><ul><li>Start at 6-8 mU/min </li></ul></ul><ul><ul><li>Increase by 6 mU/min every 15-40 minutes </li></ul></ul><ul><li>High-dose results in shorter labor, decreased intra-amniotic infections, and decreased rates of c/section for dystocia but higher risk of hyperstimulation </li></ul><ul><li>Sanchez-Ramos L. Induction of labor. Obstet Gynecol Clin North Am - 01-JUN-2005; 32(2): 181-200, viii </li></ul>
  28. 28. Dosing of Oxytocin <ul><li>Commonly accepted practice is to increase by 1-2 mU/min every 40 minutes </li></ul><ul><ul><li>May optimize pharmacokinetics by not increasing dose before steady-state is reached </li></ul></ul><ul><ul><li>Lower risk of hyperstimulation </li></ul></ul><ul><ul><li>May result in longer labor for oxytocin-insensitive women </li></ul></ul><ul><ul><li>May result in lower overall dose of oxytocin required </li></ul></ul><ul><li>Usual dose </li></ul><ul><ul><li>More than 90% of women will respond to 16 mU/min or less </li></ul></ul><ul><ul><li>Rare for women to require 20-40 mU/min </li></ul></ul>
  29. 29. Potential Risks <ul><li>Stripping membranes </li></ul><ul><ul><li>Bleeding from undiagnosed placenta previa or low-lying placenta </li></ul></ul><ul><ul><li>Accidental amniotomy </li></ul></ul><ul><li>Nipple stimulation </li></ul><ul><ul><li>Uterine hyperactivity </li></ul></ul><ul><ul><li>FHR decels </li></ul></ul><ul><li>Amniotomy </li></ul><ul><ul><li>Unpredictable length of time until onset of contractions </li></ul></ul><ul><ul><li>Cord prolapse </li></ul></ul><ul><ul><li>Chorioamnionitis </li></ul></ul><ul><ul><li>Cord compression </li></ul></ul><ul><ul><li>Vasa previa rupture </li></ul></ul><ul><li>Laminaria </li></ul><ul><ul><li>Increased maternal/fetal infections </li></ul></ul><ul><li>ACOG Practice Guideline No. 10. Induction of labor. </li></ul>
  30. 30. Potential Risks cont’d <ul><li>Misoprostol (cytotec) </li></ul><ul><ul><li>Tachysystole, hyperstimulation </li></ul></ul><ul><ul><li>Uterine rupture </li></ul></ul><ul><ul><li>Increase in meconium staining of AF </li></ul></ul><ul><ul><li>Abnl FHR tracing </li></ul></ul><ul><ul><li>Likely dose and route dependent </li></ul></ul><ul><li>Intravaginal/intracervical PGE 2 </li></ul><ul><ul><li>1-5% rate of uterine hyperstimulation </li></ul></ul><ul><ul><li>Fever, vomiting, diarrhea </li></ul></ul><ul><ul><li>Uterine rupture secondary to hyperstimulation </li></ul></ul><ul><li>Oxytocin </li></ul><ul><ul><li>Dose related </li></ul></ul><ul><ul><li>Hyperstimulation </li></ul></ul><ul><ul><li>FHR decels </li></ul></ul><ul><ul><li>Placental abruption/uterine rupture secondary to hyperstim </li></ul></ul><ul><ul><li>Water intoxication </li></ul></ul><ul><ul><li>Antidiuretic effect and hypotension with large/rapid IV administration </li></ul></ul><ul><li>ACOG Practice Guideline No. 10. Induction of labor. </li></ul>
  31. 31. Questions & Comments
  32. 32. References <ul><li>ACOG Practice Bulletin No 10 Induction of Labor, 1999. </li></ul><ul><li>Crane JM. Factors predicting labor induction success: A critical analysis 2006; Clin Obstet Gynecol 49;573-84. </li></ul><ul><li>Harman JH, Kim A. Current trends in cervical ripening and labor induction. AFP 1999;60:477-84. </li></ul><ul><li>Tenore JL. Methods for cervical ripening and induction of labor. AFP 2003;67:2123-8. </li></ul><ul><li>Weeks A. Oral misoprostol administration for labor induction. Clin Obstet Gynecol 2006;49:658-71. </li></ul>

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