Table 2.
Overview of the characteristics of the randomised controlled trials (RCTs).
| Source, Year, Country, OECD | Infant Sample (n) | Intervention Group/s | Control Group/s | Intervention Duration | Cognitive Testing Age | Cognitive Assessment Tests | Main Findings |
|---|---|---|---|---|---|---|---|
| Choline Intervention vs. Control | |||||||
| Cheatham et al. [45] 2012, US, 1 | 99 | Supplement: Vitamins: 750 mg/day choline |
Supplement: corn oil capsules | 18 weekends gestation to 3 months postnatally | 10 and 12 month | Visuospatial Memory Delayed Response Task [78,79,80], Imitation paradigms [81], CDI [82] & MSEL [83] | There were no significant differences between the intervention and control groups for global development, language, short-term visuospatial memory, or long-term episodic memory test scores (p > 0.05) at 10 and 12 months |
| Iodine Intervention vs. Control | |||||||
| Santiago et al. [54], Spain, 1 | 102 | Supplement: Mineral: I1: 200 µg/day iodine I2: 300 µg/day iodine |
Fortified food: used iodised salt | Before 10 weekends gestation to delivery | 6 to 18 month | BSID-III [34] | There were no significant differences between the groups for MDI and PDI scores (p > 0.05) at 6 to 18 months |
| Zhou et al. [70], Australia, 1 | 53 | Supplement: Mineral: 150 µg/day iodine |
No supplement | Less than 20 weekends gestation to delivery | 18 month | BSID-III [34] | There was no significant difference between the intervention compared to the control group for child cognition (p = 0.42), language (p = 0.83) and motor skills (p = 0.61) at 18 months of age |
| Zhou et al. [65], Australia, 1 | 302 | Supplement: Mineral: 20 mg/day Fe |
No supplement | 20 weekends gestation to delivery | 48 months | SB4 [84] & SDQ [85] | There were no significant differences between groups for child cognition and behaviour test scores (p > 0.05) at 48 months |
| Iron and Folic Acid or Multiple Micronutrient Intervention vs. Control | |||||||
| Chang et al. [73], China, 3 | 850 | Supplement: Vitamins: I1: 400 µg/day FA I2: 400 µg/day FA, 800 µg/day vit A, 1.4 mg/day vit B1, 1.4 mg/day vit B2, 18 mg/day B3, 1.9 mg/day vit B6, 2.6 µg/day vit B12, 70 µg/day vit C, 5 µg/day vit D, 10 mg/day vit E Minerals: I1: 60 mg/day Fe I2: 2 mg/day Cu, 150 µg/day iodine, 30 mg/day Fe, 65 µg/day Se, 15 mg/day Zn |
Supplement: Vitamin: 400 µg/day FA |
Less than 28 weekends gestation to delivery | 3,6,12,18 and 24 months | BSID-II (Chinese translation) [86,87] | The prenatal IDA intervention groups had a lower MDI (p = 0.046 in folic acid; p = 0.034 in multiple micronutrient supplements) compared to the prenatal-non-IDA group. There was no significant difference in MDI scores in the prenatal-IDA group and prenatal-non-IDA group that received iron and folic acid supplements (p = 0.641) |
| Li et al. [60], China, 2 | 1305 | Supplement: Vitamins: I1: 800 µg/day vit A, 1.4 mg/day vit B1, 1.4 mg/day B2, 18 mg/day vit B3, 1.9 mg/day vit B6, 2.6 mg/day vit B12, 70 mg/day vit C, 10 µg/day vit D, 10 mg/day vit E, 400 µg/day FA I2: 400 µg/day FA Minerals: I1: 2 mg/day Cu, 30 mg/day Fe, 150 µg/day iodine, 65 µg/day Se I2: 30 mg/day Fe |
Supplement Vitamins: 400 µg/day FA |
27 weekends gestation to delivery | 3, 6 and 12 months | BSID-II [86] | Positive effects were demonstrated from the multiple micronutrient supplement on child MDI scores at 12 months (p = 0.01) |
| Hanieh et al. [48], Vietnam, 3 | 1168 | Supplement taken twice weekly Vitamins: I1: 1500 µg/day FA I2: 1600 µg/day vit A, 2.8 mg/day vit B1, 2.8 mg/day vit B2, 36 mg/day vit B3, 3.8 mg/day vit B6, 2.8 mg/day vit B12, 140 mg/day vit C, 10 mg/day vit D, 20 mg/day vit E, 1500 µg/day FA Minerals: I1: 60 mg/day Fe I2: 4 mg/day Cu, 60 mg/day Fe, 300 µg/day iodine, 130 µg/day Se |
Supplement taken daily Vitamin: 400 µg/day FA Mineral: 60 mg/day Fe |
Less than 16 weekends gestation to 3 months postnatally | 6 months | BSID-III [34] | A positive effect was demonstrated from the twice weekly iron and folate acid supplement groups on child cognitive development scores (MD 1.89; 95% CI 0.23 to 3.56) at 6 months |
| LCPUFA s Intervention vs. Control | |||||||
| Brei et al. [72], Germany, 1 | 130 | Supplement: fish oil capsules LCPUFAs: 1020 mg/day DHA, 180 mg/day EPA Vitamin: 9 mg/day vit E Dietary counselling to lower ARA intake |
Participants received information for eating a healthy diet during pregnancy | 15 weekends gestation to 4 months postnatally | 60 months | Child Development Inventory (German translation) [88,89], MM [90,91] | There were no differences between the maternal fish oil supplemented group compared to the control group on child CDI scores and MM at 4 and 5 years of age (p > 0.05) |
| Dunstan et al. [46], Australia, 1 | 72 | Supplement: fish oil capsules LCPUFAs: 2.2 g/day DHA, 1.1 g/day EPA Vitamins: 3–4 mg/day vit E |
Supplement: olive oil capsules LCPUFA: 2.7 g/day oleic acid Vitamins: 3–4 mg/day vit E |
20 weekends gestation to delivery | 18 months | GMDS 0-2 [92], PPVT-III [93] & CBCL [94] | A positive effect was demonstrated from the maternal fish oil intervention on eye and hand coordination (p = 0.021) in children at 18 months |
| Gould et al. [47], Australia, 1 | 185 | Intervention: marine oil capsules LCPUFAs: 0.8 g/day DHA, 0.1 g/day EPA |
Supplement: capsule with a blend of vegetable oils | 18–21 weekends gestation to delivery | 27 months | Single and multiple object task [95,96] & A-not-B task [97] | There were no significant differences between the intervention and control groups for child attention, working memory and inhibitory control development test scores (p > 0.05) |
| Helland et al. [49], Norway, 1 | 262 | Supplement: cod liver oil LCPUFAs: 75 mg/day ALA, 27.5 mg/day ARA, 1.18 g/day DHA, 0.8 g/day EPA, 160 mg/day LA, Vitamins: 117 µg/day vit A, 1 µg/day vit D, 1.4 mg/day vit E |
Supplement: corn oil LCPUFAs: 92 mg/day ALA, 8.3 mg/day DHA, 4.7 g/day LA Vitamins: 117 µg/day vit A, 1 µg/day vit D, 1.4 mg/day vit E |
17–19 weekends gestation to 3 months postnatally | 27 and 39 weekends | FTII-II [98] | There were no significant differences between the intervention and control groups for cognitive development test scores (p > 0.05) at 27 and 39 months |
| Helland et al. [51], Norway, 1 | 90 | Supplement: cod liver oil LCPUFAs: 75 mg/day ALA, 27.5 mg/day ARA, 1.18 g/day DHA, 0.8 g/day EPA, 160 mg/day LA, Vitamins: 117 µg/day vit A, 1 µg/day vit D, 1.4 mg/day vit E |
Supplement: corn oil LCPUFAs: 92 mg/day ALA, 8.3 mg/day DHA, 4.7 g/day LAVitamins: 117 µg/day vit A, 1 µg/day vit D, 1.4 mg/day vit E |
1–19 weekends gestation to 3 months postnatally | 48 months | KABC-II [99] | Apositive effect was demonstrated from the cod liver oil supplement on child mental processing composite score (p = 0.049) at 48 months |
| Helland et al. [50], Norway, 1 | 143 | Supplement: cod liver oil LCPUFAs: 75 mg/day ALA, 27.5 mg/day ARA, 1.18 g/day DHA, 0.8 g/day EPA, 160 mg/day LA, Vitamins: 117 µg/day vit A, 1 µg/day vit D, 1.4 mg/day vit E |
Supplement: corn oil LCPUFAs: 92 mg/day ALA, 8.3 mg/day DHA, 4.7 g/day LA Vitamins: 117 µg/day vit A, 1 µg/day vit D, 1.4 mg/day vit E |
1–19 weekends gestation to 3 months postnatally | 84 months | KABC-II [99] | No significant differences between the intervention and control groups for cognitive development test scores (p > 0.05) at 84 months was found |
| Hurtado et al. [68], Spain, 1 | 61 | Supplement: fish oil drink per 100 mL Energy: 145 kJ Macronutrients: 3.7 g prot., 6.7 g carb., 1.8 g total fat LCPUFAs: 80 mg DHA, 18 mg EPA Vitamins: 0.4 µg vit B12, 9 mg vit C, 0.75 µg vit D, 1.5 mg vit E, 80 µg FA Minerals: 23 µg iodine, 2.2 mg Fe |
Supplement drink per 100 mL Energy: 145 kJ Macronutrients: 3.7 g prot., 6.7 g carb., 1.8 g total fat Vitamins: 0.4 µg vit B12, 9 mg vit C, 0.75 µg vit D, 1.5 mg vit E, 80 µg FA Minerals: 23 µg iodine, 2.2 mg Fe |
28 weekends gestation to 4 months postnatally | 12 months | BSID-II [86] | There were no differences between the maternal fish oil supplemented group compared to the control group on child MDI and PDI composite scores at 12 months of age |
| Judge et al. [59], US, 1 | 29 | Muesli bar with fish oil. Per bar; Energy: 386 kJ Macronutrients: 18 g carb., 0.3 g fibre, 1.3 g prot., 1.7 g total fat, 300 mg DHA, 38 mg EPA |
Muesli bar without fish oil. Per bar; Energy: 386 kJ Macronutrient: 18 g carb., 0.3 g fibre, 1.3 g prot., 1.7 g total fat |
24 weekends gestation until delivery | 9 months | 2-step problem-solving test [100,101,102,103] & FTII-II [98] | Positive effects were demonstrated from the fish oil intervention group on the problem-solving task (p = 0.017), total intentional score (p = 0.011) and the number of intentional solution on both cloth (p = 0.008) and cover steps (p = 0.004) at 9 months |
| Makrides et al. [52], Australia, 1 | 726 | Supplement: fish oil capsules LCPUFAs: 800 mg/day DHA, 100 mg/day EPA |
Supplement: Capsules with vegetable oil blend | 21 weekends gestation to delivery | 18 months | BSID-III [34] | There were no significant differences between the groups for cognitive and language test scores (p > 0.05) |
| Mulder et al. [62], Canada 4, 1 | 216 | Supplement: algal oil capsules LCPUFAs: 400 mg/day DHA |
Supplement: soybean and corn oil capsules | 16 weekends gestation to delivery | 9 and 18 months | CDI [82] & BSID-III [34] | Negative effects were demonstrated from the maternal algal oil supplement for CDI language (p < 0.05) at 14 months and 18 months and BSID-III language scores at 18 months (p < 0.05) |
| Ramakrishnan et al. [74], Mexico, 2 | 797 | Supplement: algal oil capsules LCPUFAs: 400 mg/day DHA |
Supplement: corn and soy oil capsules | 18–22 weekends Gestation to delivery | 60 months | MSCA (Spanish translation) [104], (BASC-2) [105], and (K-CPT) [106] | There were no significant differences between the intervention group compared to the control group for MSCA scores (p > 0.05), BASC-2 or scores at 5 years. of age. The intervention did significantly affect K-CPT omissions scores (p = 0.01) compared to the placebo group |
| Tofail et al. [63], Bangladesh, 4 | 249 | Supplement: fish oil capsules LCPUFAs: 1.2 g/day DHA, 1.8 g/day EPA |
Supplement: soy oil capsules LCPUFAs: 2.3 g/day LA |
27 weekends gestation to delivery | 10 months | BSID-II [86] & Wolke’s Behaviour Rating Scale [107] | There were no significant differences between the intervention and control groups for cognitive or behaviour development test scores (p > 0.05) at 10 months |
| Van Goor et al. [56], Netherlands, 1 | 114 | Fish oil capsules I1: 220 mg/day DHA, 34 mg/day EPA, 15 mg/day ARA, 274 mg/day LA, 32 mg/day ALA I2: 220 mg/day DHA, 36 mg/day EPA, 220 mg/day ARA, 46 mg/day LA, 7 mg/day ALA |
Supplement: soy bean oil capsules | 14–20 weekends gestation to 3 months postnatally | 18 months | BSID-II [86] | There were no significant differences between the control and intervention groups for cognitive development test scores (p > 0.05) at 18 months |
| LCPUFA and Folic Acid Intervention vs. Control | |||||||
| Catena et al. [66], Germany, Spain & Hungary, 1 | 136 | Dairy drink per sachet: I1: 500 mg/day DHA, 150 mg/day EPA I2: 400 µg/day FA I3: 500 mg/day DHA, 150 mg/day EPA, 400 µg/day FA | Dairy drink with vitamins and minerals in accordance to European dietary guidelines for pregnancy | Less than 20 weekends gestation to delivery | 102 months | Attention Network Test (child version) [108,109] | Children born to mothers supplemented with folic acid alone solved the response conflict more quickly than the control group and the fish oiand folic acid group (all p < 0.05) |
| Multiple Micronutrient Intervention vs. Control | |||||||
| Christian et al. [71], Nepal, 4 | 676 | Supplement: Vitamins: I1: 1000 µg/day vit A, 400 µg/day FA I2: 1000 µg/day vit A, 400 µg/day FA I3: 1000 µg/day vit A, 400 µg/day FA I4: 1000 µg/day vit A, 400 µg/day FA, 1.6 mg/day vit B1, 1.8 mg/day vit B2, 20 mg/day vit B3, 2.2 µg/day vit B6, 2.6 µg/day vit B12, 100 mg/day vit C, 10 µg/day vit D, 10 mg/day vit E, 65 µg/day vit K Minerals: I2: 60 mg/day Fe I3: 60 mg/day Fe, 30 mg/day Zn I4: 2 mg/day Cu, 60 mg/day Fe, 100 mg/day Mg, 30 mg/day Zn |
Supplement: Vitamin: 1000 µg/day vit A | Pregnancy to 3 months postnatally | 84–108 months | UNIT [110], Go/no-go [111], the Stroop test [112], backward digit span [113], MABC [114], finger-tapping test [115] | The difference across all outcomes (UNIT, executive function and motor functioning) was significant in children whose mother received iron and folic acid supplementation (p = 0.001) compared to the control group but not for the other intervention groups (p > 0.05) |
| Christian et al. [67], Bangladeshi, 4 | 734 | Supplement: Vitamins: 770 µg/day vit A, 1.4 mg/day vit B1, 1.4 mg/day vit B2, 18 mg/day vit B3, 1.9 mg/day vit B6, 2.6 µg/day vit B12, 85 mg/day vit C, 5 µg/day vit D, 15 mg/day vit E, 600 µg/day FA Minerals: 1000 µg/day Cu,220 µg/day iodine, 27 mg/day Fe, 60 µg Se, 12 mg/day Zn |
Supplement: Vitamin: 600 µg/day FA Mineral: 27 mg/day Fe |
Pregnancy to 3 months postnatally | 24 months | BSID-III [34] | There were no differences between the intervention and control group on child composite scores for cognition (p = 0.52), language (p = 0.97), and motor performance (p = 0.22) at 24 months of age |
| Joos et al. [116], Taiwan, 2 | 198 | Supplement: 1680 kJ, 50 g /day carb., 0.55 g/day fibre, 20 g/day prot., 13.3 g/day total fatVitamins: 750 µg/day vit A, 0.8 mg/day vit B1, 0.9 mg/day vit B2, 10 mg/day vit B3, 0.08 mg/day vit B6, 1 mg/day vit B12, 37.5 mg/day vit C, 5 µg/day vit D, 3.35 mg/day vit E Minerals: 0.5 mg/day Ca, 0.5 mg/day Cu, 6 mg/day Fe, 1 mg/day Mn, 0.9 mg/day K, 0.2 mg/day Na, 0.4 mg/day |
No supplement | Conception to lactation of 2nd child | 8 months | BSID-I [117] | A positive effect was demonstrated from the multiple micronutrient supplement on PDI (mean ± SD: 3.80 ± 1.90 compared to 3.31 ± 1.71) at 8 months |
| Prado et al. [53], Indonesia, 3 | 487 | Supplement Vitamins: 800 µg/day vit A, 1.4 mg/day vit B1, 1.4 mg/day vit B2, 18 mg/day vit B3, 1.9 mg/day vit B6, 2.6 mg/day vit B12, 70 mg/day vit C, 5 µg/day vit D, 100 mg vit E, 400 µg/day FA Minerals: 2 µg/day Cu, 30 mg/day Fe, 150 µg/day iodine, 65 µg/day Se |
Supplement: Vitamins: 400 µg/day FA Minerals: 30 mg/day Fe |
Pregnancy to 3 months postnatally | 42 months | BSID-II [86], ASQ [118], BPVS-II [119], BAS-2 [120], CDI [82], NEPSY [121], Snack Delay Test [122,123], Windows Test [124] & Socioemotional Development Scale [53]. | No significant differences between the intervention and control groups for child motor, language, visual attention/spatial, executive, and socio-emotional development test scores (p > 0.05) at 42 months was found |
| Tofail et al. [64], Bangladesh, 4 | 2853 | Food & supplements Energy: 2512 kJ. Vitamins: I1: 400 µg folate I2: 1.4 mg/day vit B1, 1.4 mg/day vit B2, 18 mg/day vit B3, 2.6 mg/day vit B6, 1.9 mg/day vit B12, 70 mg/day vit C, 5 µg/day vit D, 10 mg/day vit E, 400 µg/day FA Minerals: I1: 30 mg/day Fe I2: 2 mg/day Cu, 60 mg/day Fe, 150 µg/day iodine, 65 µg/day, Se 15 mg/day Zn |
Food & supplements 2512 kJ. Vitamins: I1: 400 µg folate I2: 1.4 mg/day vit B1, 1.4 mg/day vit B2, 18 mg/day vit B3, 2.6 mg/day vit B6, 1.9 mg/day vit B12, 70 mg/day vit C, 5 µg/day vit D, 10 mg/day vit E, 400 µg/day FA Minerals: I1: 30 mg/day Fe I2: 2 mg/day Cu, 60 mg/day Fe, 150 µg/day iodine, 65 µg/day, Se 15 mg/day Zn | 17 weekends gestation to delivery | 7 months | Two step problem-solving tests [100,101,102,103], BSID-II [86] & Wolke’s Behaviour Rating Scale [107] | There were no significant differences between the intervention and control groups for child problem solving ability, cognitive or behaviour development test scores (p > 0.05) at 7 months |
| Vuori et al. [76], Colombia, 2 | 244 | Food & supplements: Energy: 3595 kJ Prot: 38.4 g/day Vitamin: 1807 µg/day vit A Mineral: 18 mg/day Fe |
No supplement | 27 weekends gestation and continued during lactation | 15 days | Checkboard activity [76] | Positive effects were demonstrated from food supplements on infants that achieved habituation (70%) in comparison to the control group (56%) p < 0.05. In addition the supplemented infants moved less during testing (mean = 11.80, SD = 6.85) in comparison to the supplemented group (mean = 10.19, SD = 5.53) |
| Waber et al. [125], Colombia, 2 | 304 | Food, supplements & nutrition education 3595 kJ energy, 38.4 g prot., 25.8 g total fat. Vitamins: 1807 µg vit A, 5.4 mg vit B1, 6.6 mg vit B2, 31.6 mg vit B3, 104.6 mg vit C Mineral: 1146 mg Ca |
No supplement | 27 weekends gestation to 6 months postnatally | 4, 6, 12, 18, 24 and 36 months | GMDS 0–2 [92] & Escalona & Corman’s Albert Einstein Scales of Sensorimotor Development [126] | Positive effects were demonstrated from food supplements on subtests including personal social (p = 0.006), speech and language (p = 0.019), eye and hand coordination (p = 0.008), as well as general quotient (p = 0.003) |
| Multiple Micronutrient or Vitamin A Intervention vs. Control | |||||||
| McGrath et al. [61], Tanzania, 4 | 327 | Supplement: Vitamins: I1: 1500 µg/day vit A, 30 mg/day beta-carotene, 20 mg/day vit B1, 20 mg/day vit B2, 100 mg/day vit B3, 25 mg/day vit B6, 50 mg/day vit B12, 500 mg/day vit C, 30 mg/day vit E, 800 µg/day FA I2: 1500 µg/day vit A, 30 mg/day beta-carotene, 20 mg/day |
Supplement: Vitamins: C1: 20 mg/day vit B1, 20 mg/day vit B2, 100 mg/day vit B3, 25 mg/day vit B6, 50 mg/day vit B12, 500 mg/day vit C, 30 mg/day vit E, 800 µg/day FA C2: No supplements |
12–27 weekends gestation to 18 months in postnatal period | 6, 12 and 18 months | BSID-II [86] | Positive effects were demonstrated from the multiple micronutrient supplement by increasing PDI score by 2.6 points (95% CI: 0.1–5.1) over 6 to 18 months Vitamin A supplementation was also associated with 2.8 point increase (95% CI: 0.4-5.2) in PDI score at 6 months |
| Vitamin A, Folic Acid and Iron Intervention vs. Control | |||||||
| Schmidt et al. [69], Indonesia, 4 | 188 | Supplement: Vitamins: 4800 µg/day vit A, 500 µg/day FA Mineral: 120 mg/day Fe |
Supplement: Vitamin: 500 µg/day FA Mineral: 120 mg/day Fe |
16–20 weekends gestation to delivery | 6 and 12 months | BSID-I [117] | There were no significant effects of vitamin A supplementation on MDI and PDI scores at 6 or 12 months of age (p > 0.05). There was no significant difference between weekly compared to daily iron supplementation on child MDI and PDI scores (p > 0.05) |
| Vitamin B12 Intervention vs. Control | |||||||
| Srinivasan et al. [75], India, 3 | 178 | Supplement: Vitamin: 50 µg/day vit B12 | No supplement | Less than 14 weekends gestation to 6 weekends postnatally | 9 months | BSID-III [34] | There were no significant effects of maternal B12 supplementation on child MDI and PDI scores at 9 months (p > 0.05) |
| Zinc Intervention vs. Control | |||||||
| Hamadani et al. [58], Bangladesh, 4 | 168 | Supplement: Vitamin: 30 mg/day Zn |
No supplement | Pregnancy to delivery | 13 months | BSID-II [86] & Wolke’s Behaviour Rating Scale [107] | Negative effects were demonstrated from maternal zinc supplementation on child MDI (p = 0.04) and psychomotor development index (PDI) (p = 0.04) at 13 months |
| Tamura et al. [55], US, 1 | 347 | Supplement: Mineral: 25 mg/day Zn |
No supplement | 19 weekends gestation to delivery | 60 months | DAS [127], VSM [128], ASM [128], Knox Cube [129], PDMS-2 [130] & Grooved Pegboard [131] | There were no significant differences between the intervention and control groups for cognitive, memory or motor development test scores (p > 0.05) at 60 months |
| Zinc, Folic Acid and Iron vs. Control | |||||||
| Caulfield et al. [57], Peru, 2 | 184 | Supplement: Vitamins: 250 µg/day FA Minerals: 25 mg/day Zn, 60 mg/day Fe |
Supplement: Vitamins: 250 µg/day FA Minerals: 60 mg/day Fe |
10–14 weekends gestation to delivery | 54 months | WPPSI-III [113], bear story [132,133], the counting game [57], draw a person [134], the friendship interview [135,136], Vinelands II [97] & PBQ [137] | There were no significant differences between the intervention and control groups for child cognitive, social or behavioural development test scores (p > 0.05) at 54 moths |
ALA: alpha-linolenic acid; ARA: arachidonic acid; ASQ: Ages and Stages Questionnaire, second edition; ASM: Auditory Sequential Memory; BAS-II: British Ability Scales, second edition; BASC-2: Behavioural Assessment System for Children; BPVS: British Picture Vocabulary Scale, second edition; BSID-I: Bayley Scales of Infant Development, first edition; BSID-II: Bayley Scales of Infant Development, second edition; BSID-III: Bayley Scales of Infant Development, third edition; C1: control 1; C2: control 2, Ca: calcium; CBCL: Child Behaviour Checklist; Carb: carbohydrates; CDI: MacArthur-Bates Communicative Development Inventories; CI; confidence interval; CL: confidence level; Cu: copper; DAS: Differential Ability Scales, first edition; DHA: docosahexaenoic acid; EPA: eicosapentaenoic acid; FA: folic acid; Fe: iron; I1: intervention 1; FTII-II: Fagan Test of Infant Intelligence, second edition; I2: intervention 2; I3: intervention 3; I4: intervention 4; IDA: iron deficiency anaemia; GMDS 0–2: Griffiths Mental Development Scales for ages 0–2 years; K: potassium; KABC-II: Kaufman Assessment Battery for Children, second edition; K-CPT: Conners’ Kiddie Continuous Performance Test; LA: linoleic acid; LCPUFA: long chain polyunsaturated fatty acids; MABC: Movement Assessment Battery for Children; MD: mean difference; MDI: motor development index; MM: lower mirror movements; Mn: manganese; MSCA: McCarthy Scales of Children’s Abilities; MSEL: Mullen Scales of Early Learning; Na: sodium; NEPSY-II: A Developmental Neuropsychological Assessment, second edition; OR: odds ratio; P: phosphorus; PDI: psychomotor development index; PBQ: Preschool Behaviour Questionnaire; PDMS-2: Peabody Developmental Motor Scales, 2nd edition; PPVT-III: Peabody Picture Vocabulary Test, third edition; Prot: protein; SB4: The Stanford-Binet Intelligence Test; SD: standard deviation; DQ: Strength and Difficulties Questionnaire; Se: selenium; SE: standard error; UNIT: Universal Non-verbal Intelligence Test; Vineland II: Vineland’s Adaptive Behaviour Scales, second edition; VSM: Visual Sequential Memory; Vit: vitamin; WPPSI-III: Wechsler Preschool Primary Scale of Intelligence, third edition; Zn: zinc. OECD, the organisation for economic co-operation and development criteria: 1 = high income country, 2 = higher middle income country, 3 = lower middle income country & 4 = low income country.