Characteristics of the participants at baseline*
| Characteristic | Control (N=526) | Improved biomass (N=527) | LPG (N=361) |
| Maternal characteristics | |||
| Age—years | 27.3±7.4 | 28±7.2 | 26.9±6.7 |
| Gestational age at enrolment—weeks† | 16.2±4.3 | 16.1±4.4 | 14.6±4.2 |
| Range | 6–26 | 6–24 | 6–23 |
| Body mass index‡ | 23.2±3.1 | 23.5±3.2 | 23±3.3 |
| Parity | 2.6±2.1 | 2.8±2.3 | 2.5±2.1 |
| Health history—no. / total no. (%)§ | |||
| Anaemia | 13/526 (2.5) | 12/527 (2.3) | 6/361 (1.7) |
| Hypertension | 11/526 (2.1) | 7/527 (1.3) | 5/361 (1.4) |
| Diabetes | 0/526 (0) | 1/527 (0.2) | 1/361 (0.3) |
| HIV | 1/526 (0.2) | 0/527 (0) | 1/361 (0.3) |
| Completed primary education—no. / total no. (%) | 334/525 (63.6) | 325/527 (61.7) | 191/360 (53.1) |
| Is married—no. / total no. (%) | 277/525 (52.8) | 309/527 (58.6) | 191/360 (53.1) |
| Pre-intervention personal CO exposure—ppm¶ | |||
| Mean±SD | 1.49±1.20 | 1.46±1.20 | 1.56±1.15 |
| Median (IQR) | 1.17 (0.62–2.09) | 1.17 (0.63–1.94) | 1.29 (0.70–2.13) |
| Household characteristics | |||
| Asset index | 0.2±2.2 | −0.0±1.8 | −0.2±1.8 |
*Plus–minus values are means±SD. Across arms, differences are noted in maternal age, gestational age at enrolment, parity, maternal education, marital status and asset index.
†Gestational age at enrolment established by ultrasound.
‡The body mass index is weight in kilograms divided by the square of the height in metres.
§Health history is based on self-reported responses to questions framed as ‘Has a doctor ever diagnosed you with (health condition)?’
¶Personal CO exposure derived from valid deployments truncated at 48-hours for analysis reported in parts per million (ppm). Due to QA/QC, 146, 165 and 101 participants in the control, improved biomass and LPG arms did not have pre-intervention personal CO exposure assessments.
CO, carbon monoxide; LPG, liquefied petroleum gas.