Timing of Elective Repeat Cesarean Delivery at Term and Neonatal Outcomes

1. Timing of Elective Repeat Cesarean Delivery at Term and Neonatal Outcomes David Guernsey MD

2. Case Scenario • 26 yo G4P2 female at 36 weeks who has had a prior low transverse cesarian section • She has be an L&D 3 times already in the last 2 weeks and has called or been in the office 2 times a week. • “Dr Guernsey this baby is kicking my butt, I’m having a C-section, why can’t we just take this baby out next week since I’ll be full term”

4. Why shouldn’t I just do the C-section next week? She will be full term right…

5. Million Dollar Question • Does it make any difference in fetal outcomes if I perform a cesarean section at 37 weeks versus 40 weeks in a healthy uncomplicated pregnancy?

6. Study Design • COHORT STUDY • Used the cesarean registry from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network • 19 academic centers • Data from 1999-2002

7. Patient Selection • 28,867 repeat C-section • 24,077 had term C-sections • 13,258 patients had term repeat C-sections with no indication for immediate delivery

8. Separation by gestational weeks • 6.3% delivered at 37 weeks • 29.5% delivered at 38 weeks • 49.1% delivered at 39 weeks • 15% delivered at 40 weeks or later • Patients <39 weeks were usually older, lower BMI, white, married, insured, had a 1st trimester sono

10. Outcome Measurements • Death • Adverse respiratory outcomes (RDS, transient tachypnea of the newborn) • Hypoglycemia • Sepsis • Seizures • Necrotizing entercolitis • Hypoxic-ischemic encephalopathy • CPR • Ventalation support within 24 hours • Umbilical pH below 7 • 5 minute APGAR below 3 • NICU admission • Prolonged hospitalization (over 5 days)

12. Analysis • Incidence of an adverse outcome decreased from 37-39 weeks • 15.3% @37wks • 11.0% @38wks • 8.0% @39wks • 7.3% @40wks • Incidence of an adverse outcome increased after 40 weeks • 11.3% @41wks • 19.5% @42wks

14. Odds Ratio Compares disease in exposed and nondisease in unexposed populations with disease in unexposed and nondisease in exposed populations to determine if there is a difference in the two. (A X D)/(B X C) Compared neonatal outcomes and gestational age at delivery relative to 39 weeks

16. Odds Ratios

17. Attributable Risk • Number of cases attributable to one risk factor • (A/(A+B))-(C/(C+D)) OR • [(relative risk-1)/relative risk] X100 • Where RR=[A/(A+B)]/[C/(C+D)]

18. Attributable Risk • Attributable Risk at 37 weeks is 48% • Attributable Risk at 38 weeks is 27%

19. Study Limitations • Smaller population of patients delivered at 37 weeks • Accuracy of determining estimated gestational age (1st vs 2nd trimester sonograms) • Study does not asses fetal lung maturity • Study does not asses effect of stillbirths

20. Why do I care? • Over 1/3 of elective cesarean sections are before 39 weeks • Many of us are going to towns where we will be deciding when to do our patients cesarean sections • All of us have whiney patients

21. Conclusions • My kids are cuter than yours!