title: Association of Prenatal Ibuprofen Exposure with Birth Weight and Gestational Age: A Population-Based Sibling Study.
abstract: OBJECTIVE
  Three studies so far have investigated the effect of prenatal non-steroidal anti-inflammatory drug (NSAID) exposure on birth weight and gestational age. The aim in this study was to evaluate the association of prenatal ibuprofen with birth weight and gestational age at birth, using a sibling design in an attempt to adjust for the possibility of familial confounding.
  
  
  METHODS
  Using data from the Norwegian Mother and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN), we identified 28 597 siblings, of whom 1080 were prenatally exposed to ibuprofen and 26 824 were not exposed to any NSAID. Random and fixed effects models with propensity score adjustment were used to evaluate the effects of ibuprofen exposure on birth weight and gestational age.
  
  
  RESULTS
  Ibuprofen exposure during the first trimester was associated with a decrease in birth weight of 79 grams (95% confidence interval -133 to -25 grams). In contrast, second and/or third trimester exposure, and duration of exposure had no impact on the effect estimates. We found no association between ibuprofen exposure and gestational age at birth.
  
  
  CONCLUSIONS
  Our results suggest that prenatal exposure to ibuprofen during the first trimester is associated with a slight decrease in birth weight. The association does not seem to be attributable to shared genetics and family environment, and could be explained by either exposure to ibuprofen, or to non-shared confounding between pregnancies.
authors.affiliation: PharmacoEpidemiology and Drug Safety Research Group, School of Pharmacy, University of Oslo, Oslo, Norway.
authors.forename: Kateřina
authors.initials: K
authors.lastname: Nezvalová-Henriksen
authors.affiliation: PharmacoEpidemiology and Drug Safety Research Group, School of Pharmacy, University of Oslo, Oslo, Norway.
authors.forename: Mollie
authors.initials: M
authors.lastname: Wood
authors.affiliation: Department of Clinical Pharmacology, St Olav's University Hospital, Trondheim, Norway.|Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Olav
authors.initials: O
authors.lastname: Spigset
authors.affiliation: PharmacoEpidemiology and Drug Safety Research Group, School of Pharmacy, University of Oslo, Oslo, Norway.|Domain for Mental and Physical Health, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Hedvig
authors.initials: H
authors.lastname: Nordeng
mesh_terms: D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects; D001724:Birth Weight / Q000187:drug effects*; D002648:Child; D005260:Female; D005865:Gestational Age; D006801:Humans; D007052:Ibuprofen / Q000009:adverse effects*; D007231:Infant, Newborn; D009035:Mothers; D009664:Norway / Q000453:epidemiology; D011159:Population Surveillance / Q000379:methods; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced* / Q000453:epidemiology; D057216:Propensity Score; D011446:Prospective Studies; D035781:Siblings
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007052:Ibuprofen