The effects of a preterm labor episode prior to 34 weeks are evident in late preterm outcomes, despite the administration of betamethasone.
OBJECTIVE
We sought to assess whether betamethasone (BETA) <34 weeks reduces adverse outcomes in late preterm infants.


METHODS
We performed a retrospective cohort study of patients with spontaneous birth 34-36 6/7 weeks. We determined whether patients were exposed to preterm labor (PTL) <34 weeks and BETA and calculated the incidence of adverse respiratory and composite outcomes and neonatal intensive care unit admission. We used chi(2) analyses to determine associations between PTL+BETA and adverse outcomes, and Poisson regression to model cumulative incidence and control for confounders.


RESULTS
We enrolled 700 mother-infant pairs. The 36-week PTL+BETA infants were at increased risk of respiratory outcome (incident risk ratio [IRR], 2.73; 95% confidence interval [CI], 1.37-5.45), neonatal intensive care unit admission (IRR, 2.01; 95% CI, 1.14-3.56), and composite outcome (IRR, 1.70; 95% CI, 1.08-2.68) compared to those without PTL+BETA. Chorioamnionitis was independently associated with all adverse outcomes.


CONCLUSIONS
We hypothesize that early PTL is a surrogate for intrauterine inflammation and is responsible for the observed adverse outcomes in those with PTL+BETA.
Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. jbastek@obgyn.upenn.edu
Jamie A
JA
Bastek
Mary D
MD
Sammel
Erin C
EC
Rebele
Sindhu K
SK
Srinivas
Michal A
MA
Elovitz
D000328:Adult; D001623:Betamethasone / Q000008:administration & dosage / Q000009:adverse effects*; D002821:Chorioamnionitis / Q000139:chemically induced / Q000453:epidemiology; D015331:Cohort Studies; D016001:Confidence Intervals; D036861:Delivery, Obstetric / Q000379:methods; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000453:epidemiology / Q000209:etiology*; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data; D008423:Maternal Age; D007752:Obstetric Labor, Premature / Q000139:chemically induced* / Q000453:epidemiology* / Q000503:physiopathology; D016012:Poisson Distribution; D011247:Pregnancy; D011256:Pregnancy Outcome; D011336:Probability; D012127:Respiratory Distress Syndrome, Newborn / Q000139:chemically induced / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment; D013997:Time Factors; D055815:Young Adult
D001623:Betamethasone