Characteristics of women who used and did not use non-steroidal anti-inflammatory drugs (NSAIDs) in gestational weeks 0–12.^a

aData from the Norwegian Mother and Child Cohort Study, 1999–2006. All data are presented as a number (%). Percentages may not add up to 100% due to rounding. bThe body-mass index is the weight in kilograms divided by the square of the height in meters: underweight: <18.5 kg/m2, normal weight: 18.5–24.9 kg/m2; overweight: 25.0–29.9 kg/m2, obese: ≥30 kg/m2. cFolic acid use is reported from the 4 weeks prior to pregnancy through week 8 of gestation.