AFS cohort | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

Birth outcomes for those using | |||||||||||

Australian reference data10 | Cannabis (with or without cigarettes) | Cigarettes only | Neither | ||||||||

Full cohort | (20.5%) | (31.9%) | (47.6%) | ||||||||

Mean | N | Mean | (SD) | Mean | (SD) | Mean | (SD) | Mean | (SD) | p Value* | |

Gestational age (weeks) | 38.8% | 308 | 38.7%† | 2.7% | 37.8% | 3.8% | 39.0% | 2.0% | 38.9% | 2.3% | 0.014 |

Birth weight (g) | 3367 | 315 | 3209‡ | 698 | 2781 | 733 | 3267 | 579 | 3345 | 690 | <0.001 |

N | |||||||||||

Gestation at birth | |||||||||||

Preterm (<37 weeks) | 8.5% | 36 | 11.7%§ | 19.1% | 8.3% | 10.7% | 0.245 | ||||

Term (≥37 and <42 weeks) | 90.9% | 268 | 87.0% | 79.4% | 89.6% | 88.6% | |||||

Post-term (≥42 weeks) | 0.6% | 4 | 1.3% | 1.6% | 2.1% | 0.7% | |||||

Infant birth weight | |||||||||||

Low (<2500 g) | 6.2% | 43 | 13.7%¶ | 35.5% | 9.1% | 7.8% | <0.001 | ||||

Appropriate (≥2500 and <4000 g) | 82.3% | 241 | 76.5% | 59.7% | 81.8% | 79.9% | |||||

High (≥4000 g) | 11.5% | 31 | 9.8% | 4.8% | 9.1% | 12.3% | |||||

Weight for gestational age | |||||||||||

Small (<10th centile) | 10.0% | 64 | 21.6%** | 38.6% | 22.6% | 14.3% | 0.004 | ||||

Appropriate (≥10th and <90th centile) | 80.0% | 210 | 70.7% | 54.4% | 72.0% | 76.2% | |||||

Large (≥90th centile) | 10.0% | 23 | 7.7% | 7.0% | 5.4% | 9.5% |

*p Value comparing mothers who used cannabis, cigarettes or neither during pregnancy (Wald test from linear regression for continuous birth outcomes, χ

^{2}test for categorised birth outcomes).†p Value from one sample t test comparing mean gestational age to full cohort to Australian reference data=0.498.

‡p Value from one sample t test comparing mean birth weight to Australian reference data <0.001.

§p Value from binomial probability test comparing proportion of preterm births to Australian reference data=0.052.

¶p Value from binomial probability test comparing proportion of low birth weight to Australian reference data <0.001.

**p Value from binomial probability test comparing proportion SGA to Australian reference data <0.001.