| Placebo (n = 31) | Folic acid (n = 37) | p value | |
---|---|---|---|---|
Mothers during pregnancy | ||||
 Preintervention (14th gestational week) | ||||
  Dietary intakes |  |  |  |  |
   Energy, MJ/day |  | 8.463 (7.631, 9.296) | 7.995 (7.468, 8.522) | 0.31 |
   Dietary folate equivalents, μg/day |  | 371 (306, 437) | 388 (329, 447) | 0.71 |
  B vitamin status | ||||
   Serum folate, nmol/L |  | 50.5 (43.1, 57.9) | 49.9 (42.8, 57.1) | 0.91 |
   RBC folate, nmol/L |  | 1055 (839, 1271) | 1271 (1059, 1482) | 0.15 |
   Serum B12, pmol/L |  | 236 (209, 264) | 233 (206, 259) | 0.85 |
   Plasma homocysteine, μmol/L |  | 6.1 (5.6, 6.6) | 6.1 (5.6, 6.6) | 0.96 |
   MTHFR 677TT genotype, No. (%) |  | 4 (13) | 5 (14) | 0.91 |
 Postintervention (36th GW) | ||||
  Serum folate, nmol/L |  | 22.4 (15.9, 28.8) | 52.9 (45.8, 60.0) | < 0.001 |
  RBC folate, nmol/L |  | 907 (722, 1042) | 1864 (1650, 2078) | < 0.001 |
  Serum B12, pmol/L |  | 169 (151, 188) | 175 (152, 198) | 0.98 |
  Plasma homocysteine, μmol/L |  | 7.2 (6.5, 7.9) | 6.3 (5.8, 6.8) | 0.04 |
Neonates at birth | ||||
 Serum folate, nmol/L |  | 68.2 (57.8, 78.5) | 105.2 (93.4, 117.0) | < 0.001 |
 RBC folate, nmol/L |  | 1512 (1272, 1752) | 2216 (1856, 2575) | 0.001 |
 Serum B12, pmol/L |  | 286 (230, 342) | 259 (216, 302) | 0.42 |
 Plasma homocysteine, μmol/L |  | 9.6 (7.7, 11.4) | 10.4 (8.9, 11.9) | 0.35 |
 MTHFR 677TT genotype, No. (%) |  | 3 (13) | 4 (13) | 0.99 |
Children at 11 years | ||||
 Vitamin supplement user, No. (%) |  | 9 (30) | 8 (22) | 0.62 |
 Fortified food consumer, No. (%) |  | 28 (93) | 33 (89) | 0.87 |
 Dietary intakesa | PRIc |  |  |  |
  Energy, MJ/day | 6.400 | 6.676 (6.118, 7.234) | 6.746 (6.088, 7.404) | 0.87 |
  Dietary folate equivalents, μg/day | 270 | 276 (234, 317) | 265 (232, 299) | 0.66 |
  Vitamin B12, μg/day | 3.5 | 4.4 (3.6, 5.2) | 4.1 (3.5, 4.6) | 0.55 |
  Riboflavin, mg/day | 1.4 | 1.7 (1.4, 2.0) | 1.6 (1.4, 1.8) | 0.49 |
  Vitamin B6, mg/day | 1.4 | 1.6 (1.5, 1.8) | 1.6 (1.4, 1.8) | 0.73 |
 Biomarker statusb | cut-offc |  |  |  |
  RBC folate, nmol/L | > 309 | 595 (502, 688) | 662 (513, 810) | 0.45 |
  Serum B12, pmol/L | > 172 | 511 (418, 605) | 529 (460, 598) | 0.75 |
  Riboflavin, EGRacd | < 1.40 | 1.48 (1.38, 1.58) | 1.44 (1.37, 1.52) | 0.54 |
  Plasma homocysteine, μmol/L | < 10.7 | 6.9 (6.1, 7.7) | 6.9 (5.8, 8.0) | 0.94 |