The impact of the interaction between increasing gestational age and obstetrical risk on birth outcomes: Evidence of a varying optimal time of delivery

James M. Nicholson, L. C. Kellar, G. M. Kellar

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

Objective: To estimate the gestational age ranges that result in optimal birth outcomes for each of four risk-defined groups. Study Design: Retrospective cohort study of singleton late third-trimester deliveries at a large urban teaching hospital between July 1995 and September 2003. Low-risk, advanced maternal age, hypertensive and diabetic patients were identified and grouped. Rates, by day of gestation at delivery, of cesarean delivery, major maternal perineal trauma, low 5-min APGAR score and NICU admission were determined for each study group. Results: Each study group had meaningful changes in rates of obstetric outcomes as a function of gestational age at delivery and these patterns differed from group to group. A unique optimal time of delivery (OTD) was estimated for each group. The low-risk group OTD was calculated to be 37 weeks 1 day to 41 weeks 0 day; the advanced maternal age group OTD was 38 weeks 5 days to 39 weeks 6 days; the hypertension group OTD was 39 weeks 2 days to 40 weeks 1 day; and the diabetes mellitus group OTD was 40 weeks 3 days to 41 weeks 1 day. Conclusions: The OTD varied based on obstetrical risk. Strategies to increase the proportion of deliveries that occur within the OTD for specific risk-defined groups could theoretically improve birth outcomes.

Original languageEnglish (US)
Pages (from-to)392-402
Number of pages11
JournalJournal of Perinatology
Volume26
Issue number7
DOIs
StatePublished - Jul 2006

All Science Journal Classification (ASJC) codes

  • Pediatrics, Perinatology, and Child Health
  • Obstetrics and Gynecology

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