Table 2.
Maternal and Newborn Characteristics of Studies Included in the Meta-Analysis
| Study | Maternal age (years), mean (SD) | Maternal BMIo (kg/m2), mean (SD) | Para 0 | Vitamin B12 (pmol/L), mean (SD) | B12-deficienta | Birth weight (g), mean (SD) | LBWb | SGAc | Length of gestation (weeks), mean (SD) | Preterm birthd | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | % | n | % | n | % | n | % | n | % | ||||||
| Baker, 2009 (18) | 18 (1) | 65 (14)e | 277 | 96 | 192 (84) | 93 | 32 | 3,232 (534) | 26 | 9 | 33 | 12 | 39.7 (1.8) | 22 | 8 |
| Bergen, 2012 (19) | 30 (5) | 25 (5) | 3,208 | 57 | 188 (93) | 2,098 | 37 | 3,418 (563) | 280 | 5 | 412 | 7 | 39.9 (1.8) | 268 | 5 |
| Bhate, 2012 (20) | 23 (3) | 20 (3) | 165 | 71 | 145 (84) | 148 | 69 | 2,707 (411) | 49 | 25 | NA | NA | 38.6 (2.6) | 18 | 8 |
| Chen, 2015 (21) | 31 (5) | 66 (12)e | 420 | 43 | 220 (79) | 161 | 16 | 3,101 (449) | 76 | 8 | 86 | 9 | 38.6 (1.4) | 85 | 9 |
| Dayaldasani, 2014 (22) | 30 (6) | 26 (5) | 96 | 51 | 387 (123) | 0 | 0 | 3,267 (526) | 11 | 6 | 12 | 7 | 38.8 (1.9) | 14 | 8 |
| Dwarkanath, 2013 (23) | 24 (4) | 53 (10)e | 203 | 59 | 205 (115)f | 100 | 29f | 2,771 (498) | 95 | 28 | 102 | 30 | 38.3 (1.7) | 47 | 14 |
| Furness, 2013g (24) | 33 (7) | 27 (5) | NA | NA | 234 (129) | NA | NA | 3,390 (789) | NA | NA | 21 | 25h | 38.8 (2.9) | NA | NA |
| Halicioglu, 2012g (25) | 28 (5) | NA | NA | NA | 120i | 99 | 48j | 3,357 (466) | NA | NA | NA | NA | NA | NA | NA |
| Hay, 2010 (26) | 30 (4) | 65 (10)e | 67 | 45 | 294 (87) | 2 | 1 | 3,727 (476) | 0 | 0 | NA | NA | NA | NA | NA |
| Hogeveen, 2010 (27) | 33 (4) | NA | 109 | 30 | 186 (69) | 120 | 34 | 3,436 (545) | 18 | 5 | 19 | 5 | 39.5 (1.6) | 21 | 6 |
| Kaymaz, 2011 (28) | 27 (3) | 24 (4) | 45 | 44 | 152 (59) | 54 | 52 | 3,241 (553) | 5 | 5 | NA | NA | 38.4 (1.9) | 9 | 9 |
| Krishnaveni, 2013 (29) | 24 (4) | 24 (4) | 331 | 51 | 187 (100) | 264 | 40 | 2,857 (475) | 126 | 19 | 202 | 32 | 39.0 (1.8) | 63 | 10 |
| Mamabolo, 2006g (30) | 25 (7) | 27 (4) | NA | NA | 175 (77) | 36 | 16k | 3,120 (550) | NA | NA | 66 | 30l | NA | NA | NA |
| Relton, 2005g (31) | 28 (6)m | NA | NA | 43m | 239 (97) | NA | NA | 3,430 (470)m | NA | NA | NA | NA | NA | NA | NA |
| Sukumar, 2011 (32) | 31 (6) | 27 (6) | 68 | 33 | 168 (126) | 114 | 55 | 3,381 (558) | 10 | 5 | 16 | 8 | 39.3 (1.7) | 9 | 4 |
| Takimoto, 2007g (33) | 29 (5) | 21 (3) | NA | NA | 405 (146)f | 13 | 16n | 3,120 (411) | 5 | 5 | NA | NA | 39.6 (1.0) | NA | NA |
| Wu, 2013g (34) | 33 (4) | NA | NA | NA | 224 (96) | 51 | 24 | 3,486 (452) | NA | NA | NA | NA | NA | NA | NA |
| Yajnik, 2008 (35) | 21 (4) | 18 (2) | 252 | 31 | 151 (78) | 447 | 59 | 2,612 (392) | 230 | 33 | NA | NA | 38.8 (2.1) | 87 | 11 |
Studies are referred to according to their citation number in the text. BMI, body mass index; LBW, low birth weight; NA, not available; SD, standard deviaton; SGA, small-for-gestational-age.
B12 <148 pmol/L;
birth weight <2,500 g;
birth weight SD score (i.e. accounting for length of gestation and sex) below 10th centile;
length of gestation <37 weeks;
kg (BMI not available);
first measurement;
data extracted from publication;
serial tapering of growth in abdominal circumference and of estimated fetal weight below the 10th centile of an Australian growth chart;
median (range not available);
B12 ≤118 pmol/L;
B12-deficiency not defined;
lowest birth weight tertile (mean birth weight 2,940 g) used as approximation of SGA for the purpose of this review;
based on a larger study population than the subgroup with available B12 data included in this review (n=974-997);
third trimester
weight (kg)/height (m)2.