Compliance of maternal folic acid supplementation and risk for allergic symptoms, asthma and hospitalisation due to asthma in offspring, 2000–2001 n (%)
| Folic acid | Compliance# | ||||||
| Periconception | Preconception | Postconception | p Value | Not compliant (340) | Compliant (3354) | p Value | |
| Subjects | 2360 | 229 | 1101 | 340 | 3354 | ||
| Allergic symptoms | 28 (1.19) | 5 (2.18) | 18 (1.63) | 0.384 | 3 (0.88) | 48 (1.43) | 0.443 |
| Asthma | 15 (0.64) | 1 (0.44) | 10 (0.91) | 0.765 | 4 (1.18) | 22 (0.66) | 0.522 |
| Hospitalisation due to asthma | 4 (0.17) | 2 (0.87) | 10 (0.91) | 0.479 | 0 (0) | 4 (0.12) | 0.565 |
Data are presented as n or n (%), unless otherwise stated. Values for some characteristics may not be equal to total numbers in each group because of missing values. #: Compliance was calculated as actual consumed pills divided by expected pills, compliant refers to compliance >80% and not compliant refers to compliance <80%.