Baseline characteristics of women for singleton pregnancies included in the analysis by treatment group
| Characteristic | Omega-3 (N=2654) | Control (N=2674) |
| Consumed omega-3 containing supplements in previous 3 months: n/N (%) | 356/2654 (13.4) | 357/2674 (13.4) |
| Maternal age: median (IQR) | 30.0 (26.0–34.0) | 30.0 (27.0–33.0) |
| Gestational age (weeks) at trial entry: median (IQR) | 14.1 (12.7–16.4) | 14.2 (12.7–16.6) |
| White race: n/N (%) | 1965/2649 (74.2) | 1969/2669 (73.8) |
| Completed high school education: n/N (%) | 2153/2644 (81.4) | 2128/2667 (79.8) |
| Currently employed: n/N (%) | 1921/2643 (72.7) | 1920/2665 (72.0) |
| Weight at trial entry (kg): median (IQR) | 69.4 (60.6–81.1) | 69.0 (60.9–81.0) |
| Smoked cigarettes leading up to pregnancy: n/N (%) | 404/2639 (15.3) | 407/2665 (15.3) |
| Drank alcohol leading up to pregnancy: n/N (%) | 1446/2642 (54.7) | 1505/2666 (56.5) |
| Any previous births ≥20 weeks: n/N (%) | 1473/2643 (55.7) | 1502/2666 (56.3) |
| ALA: median (IQR) | 0.5 (0.4–0.7) | 0.6 (0.4–0.7) |
| EPA: median (IQR) | 0.5 (0.4–0.6) | 0.5 (0.4–0.6) |
| DPA: median (IQR) | 1.0 (0.9–1.1) | 1.0 (0.9–1.1) |
| DHA: median (IQR) | 2.7 (2.3–3.1) | 2.7 (2.3–3.1) |
| EPA+DHA: median (IQR) | 3.2 (2.8–3.6) | 3.2 (2.7–3.7) |
| Total omega-3: median (IQR) | 4.8 (4.3–5.3) | 4.8 (4.3–5.3) |
Total omega-3 is the sum of ALA, EPA, DPA and DHA.
ALA, alpha-linolenic acid; DHA, docosahexaenoic acid; DPA, docosapentaenoic acid; EPA, eicosapentaenoic acid; IQR, interquartile range.