This document summarizes information about preterm labor prevention and treatment. It defines preterm labor and discusses risk factors like prior preterm birth, infections, and cervical length. Interventions discussed include progesterone supplementation, treating asymptomatic bacteriuria, and cervical cerclage for short cervix. Fetal fibronectin testing and transvaginal ultrasound are presented as tools to assess preterm labor risk based on cervical length and funneling.

1. Preterm Labor Prevention and Treatment Kerry Watrin MD August 2 nd 2007

4. Race/Ethnicity and Prematurity 2000to 2002 1.5% 10.7% White 1.4% 10.2% Asian 1.7% 11.4% Hispanic 2.0% 12.9% Native American 4.1% 17.6% Black 1.9% 11.9% All US < 32wk US < 37wk Race/Ethnicity

11. Expected pregnancy weight gain 15+ lbs > 29 Obese 15-25 lbs 26-29 High 25-35 lbs 19.8-26 Normal 28-40 lbs <19.8 Low Recommended wt gain BMI Kg/m2 Wt/ht category

14. Bacterial Vaginosis: Clue cell

20. Preterm outcomes and Progesterone NNT Relative Risk Placebo N=153 Progest N=306 7 0.66 (.51-.87) 62 41.1% 82 27.2% LBW < 2500 gm 12 0.58 (.37-.91) 30 19.6% 35 11.4% Delivery < 32 wk 10 0.67 (.48-.93) 47 30.7% 63 20.6% Delivery < 35 wk 5 0.66 (.54-.81) 84 54.9% 111 36.3% Delivery < 37 wk

33. Rate of Preterm Birth <35 weeks by Cervical Length at 24 weeks 34 % < 13 mm 20 % <20 mm 8 %  25 mm Rate Delivery Length

34. Ultrasound Cervical Length Prediction of PTB < 35 weeks 17.2% 96.6% 94.5% 25.4% Funneling At 24 wk 17.8% 97% 92.2% 37.3% 25mm 24 weeks 16.7% 97.6% 94.7% 31.3% 20 mm 28 weeks 25.7% 96.7% 97% 23% 20mm 24 weeks PPV NPV Specificity Sensitivity Finding

42. Contractions what to do? 4 (7%) 4 (6%) 5 (9%) PTB < 34 wks $687 $966 $717 Mean cost < 24 hours 5 (8%) 8 (13%) 7 (13%) admitted 8 (13%) 8 (13%) 10 (18%) More tocolysis 79% 57% 64% Triage < 4hrs 4.1  5.1 hrs 6.0  5.7 hrs 5.2  5.1 hrs Mean time to discharge Terbutaline x1, n=61 Hydration N=62 Observation N=56

45. The Recommendations MMWR, Vol 51 (RR-11)

87. Risk of Preterm Birth < 35 weeks compared to cervical length of the 75% 1.0 1.0 75% 40 mm 9.5 6.7 10% 26 mm 13.9 9.5 5% 22 mm 24.9 14 1% 13 mm 28 weeks RR of PTB 24 weeks RR of PTB Percentile On Curve Length

90. Tocolytics:  - mimetics 2004 Systematic Review OR 0.79 CI (0.61-1.01) 5 RTC 55%, 332/601  mimetic 65%, 332/525 placebo LBW < 2,500 gms OR 0.76 CI (0.57-1.01) 6 RTC 18%, 117/639  mimetic 25%, 140/565 placebo RDS OR 1.08 CI (0.72-1.62) 7 RTC 9%, 62/682  mimetic 8%, 48/604 placebo Perinatal Mortality OR Sample Finding