Table 2.
Nutritional factors with potential indirect associations with pre-eclampsia incidence via medical conditions (95 % confidence intervals)
| Dietary or nutritional factor | Effect estimate | 95 % CI | Number of studies | Number of participants | I 2 | Quality of evidence |
|---|---|---|---|---|---|---|
| Maternal anaemia | ||||||
| Vitamin A supplementation* (56) | RR 0·64 | 0·43, 0·94 | 3 | 15 649 | 68 % | Moderate |
| Fe supplementation* (44) | RR 0·30 | 0·19, 0·46 | 14 | 2199 | 80 % | Moderate |
| Fe–folic acid supplementation* (44) | RR 0·34 | 0·21, 0·54 | 3 | 346 | 0 % | High |
| Gestational diabetes mellitus | ||||||
| Vitamin D deficiency(60) | OR 1·43 | 1·23, 1·67 | 36 | 30 973 | 73 % | Low |
| Vitamin B12 < 200 pg/ml(61) | OR 1·81 | 1·25, 2·63 | 2 | 1129 | 0 % | High |
| Vitamin D supplementation* (37,55) | RR 0·51 | 0·27, 0·97 | 4 | 446 | 0 % | Moderate |
| Healthy maternal dietary pattern* (39) | OR 0·78 | 0·56, 0·99 | 5 | 6057 | 69 % | Moderate |
| Ultra-processed foods dietary pattern(54) | OR 1·48 | 1·17, 1·87 | 10 | 42 477 | 83 % | Low |
| Obesity | ||||||
| Vitamin D deficiency(63) | OR 3·43 | 2·33, 5·06 | 15 | 13 209 | 81 % | Low |
| Serum folate <10 nmol/l(66) | aOR 2·03 | 1·35, 3·06 | 1 | 4243 | N/A | High |
| Serum Fe <11 μmol/l(66) | aOR 3·26 | 2·09, 5·08 | 1 | 4243 | N/A | High |
| Serum vitamin B12 < 203·3 pg/ml(66) | aOR 2·05 | 1·41, 2·99 | 1 | 4243 | N/A | High |
| Low diet quality (Diet Quality Index for Pregnancy)(67) | aOR 1·76 | 1·24, 2·49 | 1 | 2394 | N/A | Moderate |
| Maternal depression | ||||||
| Maternal 25(OH)D* (65) | OR 0·49 | 0·35, 0·63 | 6 | 10 317 | 82 % | High |
| Chronic hypertension | ||||||
| Low diet quality (Healthy Eating Index)(68) | RR 2·67 | 1·67, 4·25 | 1 | 8259 | N/A | Low |
RR, relative risk.
*
Protective effects.