Maternal Prepregnancy BMI and Risk of Cerebral Palsy in Offspring.
To investigate the association between maternal pre-pregnancy BMI and risk of cerebral palsy (CP) in offspring.



The study population consisted of 188 788 children in the Mothers and Babies in Norway and Denmark CP study, using data from 2 population-based, prospective birth cohorts: the Norwegian Mother and Child Cohort Study and the Danish National Birth Cohort. Prepregnancy BMI was classified as underweight (BMI <18.5), lower normal weight (BMI 18.5-22.9), upper normal weight (BMI 23.0-24.9), overweight (BMI 25.0-29.9), and obese (BMI ≥30). CP diagnoses were obtained from the national CP registries. Associations between maternal prepregnancy BMI and CP in offspring were investigated by using log-binomial regression models.



The 2 cohorts had 390 eligible cases of CP (2.1 per 1000 live-born children). Compared with mothers in the lower normal weight group, mothers in the upper normal group had a 40% excess risk of having a child with CP (relative risk [RR], 1.35; 95% confidence interval [CI], 1.03-1.78). Excess risk was 60% (RR, 1.56; 95% CI, 1.21-2.01) for overweight mothers and 60% (RR, 1.55; 95% CI 1.11-2.18) for obese mothers. The risk of CP increased ∼4% for each unit increase in BMI (RR, 1.04; 95% CI, 1.02-1.06). Estimates changed little with adjustment for mother's occupational status, age, and smoking habits.



Higher prepregnancy maternal BMI was associated with increased risk of CP in offspring.
Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; ingeborg.forthun@uib.no.|Department of Pediatrics, Haukeland University Hospital, Bergen, Norway.
Ingeborg
I
Forthun
Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina.
Allen J
AJ
Wilcox
Section of Social Medicine, Department of Public Health, University of Copenhagen, Copenhagen, Denmark.
Katrine
K
Strandberg-Larsen
Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.|Department of Pediatrics, Haukeland University Hospital, Bergen, Norway.|Norwegian Institute of Public Health, Oslo, Norway; and.
Dag
D
Moster
Research Unit for Gynaecology and Obstetrics, Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.
Ellen A
EA
Nohr
Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
Rolv Terje
RT
Lie
Norwegian Institute of Public Health, Oslo, Norway; and.
Pål
P
Surén
Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.|Norwegian Institute of Public Health, Oslo, Norway; and.
Mette C
MC
Tollånes
D000328:Adult; D015992:Body Mass Index; D002547:Cerebral Palsy / Q000453:epidemiology*; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D009035:Mothers; D009664:Norway / Q000453:epidemiology; D050177:Overweight / Q000453:epidemiology*; D011247:Pregnancy; D015995:Prevalence; D012306:Risk; D055815:Young Adult