1. Preterm Birth Yinka Oyelese, MD, MRCOG Associate Professor, Maternal Fetal Medicine UTHSC

2. Preterm birth rates in the United States < 37 weeks 12.9% %

3. Preterm birth in the US One preterm birth every minute!

9. Costs affect insurance rates, taxes, and PAY CHECKS!

10. Sources of preterm birth, United States 2000 Ananth et al, Obstet Gynecol, 2006 Overall (%) Singletons (%) Twins (%) Spontaneous 60 69 44 Medically indicated 40 31 56

11. Preterm births in the United States

12. Spontaneous PTB Medically indicated PTB Preterm PROM

13. SPB Source of Preterm Birth Tucker et al. Obstet Gynecol 1991 Spontaneous 30-50% Preterm PROM 30-40% Indicated 20-30%

14. Medically indicated Spontaneous Overall SROM

15. Preterm Birth Changes between 1989-00, US Whites Blacks All PTB 14% 15% Spont PTB 3% 27% Med-ind 55% 32% PNM 30% 25%

16. Preterm Birth Trends Whites (%) Blacks (%) 89 00 Δ % 89 00 Δ % Total PTB 8.3 9.4 14 18.5 16.2 -15 pPROM 1.1 0.8 -23 2.3 1.5 -37 Med-ind 2.3 3.6 55 4.1 5.6 32 Spt labor 4.9 5.0 3 12.1 9.1 -27

17. Indicated Preterm Birth Tucker et al. 1991 Meis et al. 1986 Singletons Twins Preeclampsia 43% 44% FGR/fet dist 37% 33% Abruption 7% 9% Fetal death 7% 7%

18. Ananth and Vintzileos AJOG 2006 Ischemic Placental Disease Among… Ischemic placental disease present in Term births 1 in 10 births Preterm births 1 in 4 births Indicated preterm births ≥ 1 in 2 births

20. Etiologies Stress Infection Bleeding Uterine overdistension

22. Some pathways through which preterm birth may occur

23. Some pathways through which preterm birth may occur

27. Recurrence of preterm birth

28. Recurrence of preterm birth

30. Average length of gestation by plurality

32. More than 1/2 of patients who deliver preterm have no risk factors More than 2/3 of patients with traditional risk factors do not deliver preterm Most important traditional risk factor is preterm delivery in a prior pregnancy

33. Fetal fibronectin

35. Fetal fibronectin

44. Transvaginal sonographic cervical assessment

46. Are there any therapeutic interventions to prevent SPTB?

50. Cerclage for dilated cervix with membranes at or beyond the external os Althusius et al, Am J Obstet Gynecol 2003 Cerclage & Indomethacin (n=13) Bedrest alone (n=10) Prolongation (weeks) 7.7 3.0 Neonatal survival 56% 28% Preterm birth <34 weeks 54% 100% Composite neonatal morbidity 62% 100%

53. Multicenter Randomized Trial of Cerclage For Preterm Birth Prevention In High-Risk Women With Shortened Mid-Trimester Cervical Length (Owen J, Abst #4, Am J Obstet Gynecol Suppl Dec 2008) Reduction in PTB < 35 wks in cerclage patients OR (95% CI) If CL < 15 mm 0.23 (0.08, 0.66) If CL 16-24 mm 0.84 (0.49, 1.40) P=0.05 CONCLUSION: Cerclage will mostly benefit high-risk women with mid-trimester CL < 15 mm (77% reduction in PTB rate)

55. Magnesium sulfate! Good or evil?

63. Progesterone

64. Progesterone for the reduction of risk of preterm birth