Table 4.
Summary of meta-analyses of randomized controlled trials on vitamin D in pregnancy in relation to offspring health.
| Outcomes | First author | Year | No. of studies in MA | Comparator (vitamin D supplementation or level) | Effects model | Metric of MA | Effect size | 95% CI | I2 (%) | Publication bias |
|---|---|---|---|---|---|---|---|---|---|---|
| Birth length | Liu | 2022 | 20 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | MD | 0.269 cm | (0.024–0.514)* | 63 | NA |
| Low birth weight rate | Liu | 2022 | 10 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | RR | 0.902 | (0.655–1.242) | 32 | NA |
| Birth weight | Liu | 2022 | 33 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | MD | 37.07 g | (-9.669–83.801) | 77 | NA |
| Head circumference | Liu | 2022 | 18 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | MD | 0.149 cm | (-0.016 ~ 0.315) | 68 | NA |
| Small-for-gestational-age | Liu | 2022 | 14 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | RR | 0.836 | (0.633 ~ 1.104) | 20 | NA |
| Macrosomia | Liu | 2022 | 3 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | RR | 1.097 | (0.600 ~ 2.007) | 0 | NA |
| Femur length in the third trimester | Luoa | 2022 | 2 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | MD | 0.16 | (-0.07 ~ 0.40) | 60 | NA |
| humeral length in the third trimester | Luoa | 2022 | 2 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | fixed-effect | MD | 0.13 | (0.06 ~ 0.21)* | 0 | NA |
| Congenital anomalies | Liu | 2022 | 4 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | RR | 0.759 | (0.439 ~ 1.314) | 56 | NA |
| 1-min Apgar score | Liu | 2022 | 4 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | MD | 0.093 | (-0.004 ~ 0.190) | 20.5 | NA |
| 5-min Apgar score | Liu | 2022 | 4 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | MD | 0.041 | (-0.051 ~ 0.133) | 43.6 | NA |
| Newborn NICU admission or hospitalization | Liu | 2022 | 5 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | RR | 1.00 | (0.830 ~ 1.205) | 0 | NA |
| Asthma or wheeze | Luo | 2022 | 4 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | fixed-effect | RR | 1.01 | (0.81 ~ 1.26) | 47 | NA |
| Eczema | Luo | 2022 | 3 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | fixed-effect | RR | 0.95 | (0.80 ~ 1.13) | 0 | NA |
| Allergic rhinitis | Luo | 2022 | 3 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | fixed-effect | RR | 0.93 | (0.78 ~ 1.11) | 47 | NA |
| Fetal or neonatal mortality | Liu | 2022 | 13 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | RR | 0.69 | (0.482 ~ 0.985)* | 0 | NA |
| Lower respiratory tract infection | Luo | 2022 | 3 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | fixed-effect | RR | 0.97 | (0.85 ~ 1.11) | 0 | NA |
| Hyperbilirubinemia | Wang | 2021 | 7 | supplement vs placebo or nothing | fixed-effect | RR | 0.47 | (0.33 ~ 0.67)* | 0 | NA |
| Macrosomia | Wang | 2021 | 6 | supplement vs placebo or nothing | fixed-effect | RR | 0.58 | (0.38 ~ 0.89)* | 0 | NA |
| Fetal distress | Wang | 2021 | 2 | supplement vs placebo or nothing | fixed-effect | RR | 0.46 | (0.24 ~ 0.90)* | 0 | NA |
| Polyhydramnios | Wang | 2021 | 4 | supplement vs placebo or nothing | fixed-effect | RR | 0.42 | (0.24 ~ 0.72)* | 0 | NA |
| Hypoglycemia | Wang | 2021 | 4 | supplement vs placebo or nothing | fixed-effect | RR | 0.82 | (0.52 ~ 1.29) | 0 | NA |
| Hospitalization | Wu | 2023 | 4 | high dose (⩾ 400 IU/day) vs placebo | fixed-effect | OR | 0.29 | (0.16 ~ 0.53)* | 0 | NA |
| Vitamin D insufficiency | Liu | 2022 | 12 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | RR | 0.508 | (0.384 ~ 0.673)* | 96 | NA |
| Vitamin D concentration | Liu | 2022 | 25 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | random-effect | MD | 27.7 | (20.5 ~ 34.9)* | 98 | NA |
| WB-BMC | Luoa | 2022 | 2 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | fixed-effect | MD | 1.09 | (-0.64 ~ 2.81) | 0 | NA |
| WB-BMD | Luoa | 2022 | 2 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | fixed-effect | MD | 0.00 | (0.00 ~ 0.00) | 0 | NA |
| WB-BA | Luoa | 2022 | 2 | high dose (> 400 IU/day) vs low dose (≤ 400 IU/day) or placebo | fixed-effect | MD | 3.71 | (-1.75 ~ 9.18) | 0 | NA |
MA meta-analysis, RR relative risk, MD mean difference, NA not available, *: significant difference, WB-BMC whole body bone mineral content, WB-BMD whole body bone mineral density, WB-BA whole body bone area, NICU neonatal intensive care unit.