Table 1.
Characteristics of the 127 mother–child pairs and all other women enrolled in the MINIMat trial a
| Study sample (n=127) | All women (n=1729) | |
|---|---|---|
| Variables | Mean±s.d. or median (5–95 percentiles) or n (%) | Mean±s.d. or median (5–95 percentiles) or n (%) |
| Maternal characteristics | ||
| Maternal age (years) | 25.3±5.9 | 26.4±5.9 |
| BMI (kg/m2) at GW 8 | 20.4±3.0 | 20.1±2.7 |
| Parity (no. of children) | 1.1±1.4 | 1.4±1.4 |
| 0/⩾1 | 54 (43%)/73 (57%) | 548 (32%)/1179 (68%) |
| Gestational age (week, GW) | 38.7±1.8 | 38.8±2.1 |
| <37/⩾37 | 12 (10%)/112 (90%) | 254 (15%)/1444 (85%) |
| Betel chewing during pregnancy | ||
| Yes/No | 73 (58%)/52 (42%) | 1150 (68%)/531 (32%) |
| Socioeconomic status | ||
| Lowest | 19 (15%) | 315 (18%) |
| Lower middle | 12 (9%) | 349 (20%) |
| Middle | 24 (19%) | 353 (20%) |
| Upper middle | 36 (28%) | 350 (20%) |
| Highest | 36 (28%) | 362 (21%) |
| Urinary arsenic GW 8 (µg/l) b | 66 (20–457) | 66 (17–466) c |
| Inorganic arsenic (%) d | 13.8±5.5 | na |
| MMA (%) d | 10.06±3.6 | na |
| DMA (%) d | 76.12±7.5 | na |
| Urinary arsenic GW 30 (µg/l) d | 89 (18–562) | 80 (19–610) c |
| Infant characteristics | ||
| Birth weight (g) | 2780±395 | 2709±409 |
| Low birth weight (<2500 g) | 26 (21%) | 504 (25%) |
| Sex (% girls) | 65 (51%) | 845 (49%) |
BMI, body mass index; GW, gestational week; MMA, methylarsonic acid; DMA, dimethylarsinic acid.
a
Enrollment in the MINIMat trial from October 2002 to October 2003.
b
Adjusted to average specific gravity of 1.012 g/ml.
c
In MINIMat, urinary arsenic was measured at GW 8 (n=1729) and GW 30 (n=1031).
d
Percent of total metabolite concentration in urine. Urinary arsenic refers to inorganic arsenic and its methylated metabolites in urine.