Sample characteristics
| Pooled cohort (n=667) | Arm 1 (n=217) | Arm 2 (n=230) | Arm 3 (n=220) | Unadjusted pairwise arm comparisons | |
| Age at INTER-NDA assessment, month | 24.6±0.9 | 24.4±0.8 | 24.4±0.8 | 24.±0.6 | F=0.15, p=0.86 |
| Perinatal characteristics | |||||
| Female | 344 (51.6) | 110 (50.7) | 126 (54.8) | 108 (49.1) | χ2=1.56, p=0.46 |
| Male | 323 (48.4) | 107 (49.3) | 104 (45.2) | 112 (50.9) | |
| Maternal age at birth, years | 23.3±4.1 | 23.0±4.0 | 23.3±4.3 | 23.4±3.7 | F=0.06, p=0.94 |
| Parity | |||||
| Nulliparous | 135 (20.2) | 53 (24.4) | 43 (18.7) | 39 (17.7) | χ2=12.76, p=0.24 |
| 1 | 190 (28.5) | 63 (29.0) | 62 (27.0) | 65 (29.5) | |
| 2 | 159 (23.8) | 43 (19.8) | 58 (25.2) | 58 (26.4) | |
| 3 | 78 (11.7) | 21 (9.7) | 30 (13.0) | 27 (12.3) | |
| 4 | 55 (8.2) | 19 (8.8) | 23 (10.0) | 13 (5.9) | |
| 5 | 28 (4.2) | 10 (4.6) | 5 (2.2) | 13 (5.9) | |
| Missing | 22 (3.3) | 8 (3.7) | 9 (3.9) | 5 (2.7) | |
| Gestational age* at birth, week | 39.2±4.2 | 39.1±2.2 | 39.2±1.5 | 39.4±7.0 | F=0.25, p=0.78 |
| Delivery Mode | |||||
| Normal | 560 (84.0) | 178 (82.0) | 195 (84.8) | 187 (85.0) | χ2=3.93, p=0.42 |
| Assisted† | 6 (0.9) | 3 (1.4) | 0 (0) | 3 (1.4) | |
| Caesarean section‡ | 101 (15.1) | 36 (16.6) | 35 (15.2) | 30 (13.6) | |
| Postnatal health and growth | |||||
| Number of children admitted to hospital for ≥3 days in the first 2 years of life | 45 (6.7) | 19 (8.8) | 14 (6.1) | 12 (5.5) | χ2=0.83, p=0.66 |
| Breast fed at 6 months | 663 (99.4) | 216 (99.5) | 227 (98.7) | 220 (100.0) | χ2=3.32, p=0.19 |
| WAZbirth | −1.11±0.92 | −1.08±0.93 | −1.09±0.92 | −1.14±0.91 | F=0.23, p=0.79 |
| LAZbirth | −1.06±1.10 | −0.94±1.17 | −1.07±1.04 | −1.15±1.03 | F=2.00, p=0.14 |
| HCAZbirth | −0.79±1.09 | −0.74±1.10 | −0.83±1.06 | −0.78±1.10 | F=0.37, p=0.69 |
| WAZ12 | −1.50±1.19 | −1.43±1.19 | −1.55±1.17 | −1.51±1.20 | F=0.56, p=0.57 |
| LAZ12 | −1.90±1.17 | −1.80±1.13 | −1.95±1.27 | −1.96±1.10 | F=1.30, p=0.27 |
| HCAZ12 | −1.18±1.08 | −1.19±1.10 | −1.23±1.04 | −1.11±1.11 | F=0.73, p=0.49 |
| WAZ24 | −1.76±1.11 | −1.71±1.14 | −1.81±1.08 | −1.76±1.10 | F=0.51, p=0.60 |
| LAZ24 | −2.38±1.15 | −2.30±1.13 | −2.46±1.16 | −2.39±1.15 | F=1.03, p=0.36 |
| HCAZ24 | −1.22±1.03 | −1.26±1.08 | −1.23±0.99 | −1.18±1.01 | F=0.28, p=0.76 |
| Family environment | |||||
| Maternal education, years | 4.5±4.2 | 4.6±4.5 | 4.7±4.1 | 4.2±4.0 | F=0.47, p=0.62 |
| Socio-economic status§ | 4.4±2.9 | 4.4±2.9 | 4.7±2.9 | 4.3±2.7 | F=0.92, p=0.40 |
| FCI: play activities§ | 5.5±2.0 | 5.5±2.1 | 5.6±1.8 | 5.4±1.9 | F=0.32, p=0.73 |
| FCI: varieties of play materials¶ | 4.4±1.7 | 4.4±1.6 | 4.4±1.7 | 4.3±1.7 | F=0.71, p=0.49 |
| FCI: sources of play materials¶ | 2.4±0.7 | 2.4±0.7 | 2.4±0.7 | 2.4±0.7 | F=0.03, p=0.97 |
| FCI: household books¶ | 0.3±0.8 | 0.4±0.9 | 0.3±0.7 | 0.3±0.8 | F=0.47, p=0.63 |
Date presented as mean±SD or n (%).
Arm 1: preconception intervention; arm 2: prenatal intervention; arm 3: no intervention.
*Gestational age data not available for Democratic Republic of the Congo.
†Ventouse or forceps-assisted delivery.
‡Emergency or elective caesarean section.
§Socio-economic status tally provides the number of indicators available from the following list: electricity, improved water source, sanitation, synthetic flooring, improved cooking fuels, transportation and household assets.
¶Assessed at 24 months.
F, analysis of variance test statistic; FCI, family care indicators; HCAZbirth, HCAZ12, HCAZ24, WHO z-scores for head circumference at birth, 12 and 24 months; INTER-NDA, INTERGROWTH-21st Neurodevelopment Assessment; LAZbirth, LAZ12, LAZ24, WHO z-scores for length at birth, 12 and 24 months; WAZbirth, WAZ12, WAZ24, WHO z-scores for weight at birth, 12 and 24 months.