Table 2.
Risk ratios and differences for the relation between smoking any time during pregnancy (relative to no smoking) and small for gestational age birth defined as birthweight less than the 10th percentile of a national birthweight standard (SGAB), estimated fetal weight + birthweight standard (SGAFB), and five different predicted fetal weights + birthweight (SGAPB) standard in a validation sub-sample of 8,517 pregnancies (13,354 ultrasound visits) at the Magee-Womens Hospital, University of Pittsburgh Medical Center, Pittsburgh, PA, 2010–2013.
| Method | Risk Ratio | 95% Robust CI | Risk Difference per 100 Live Births | 95% Robust CI | ||
|---|---|---|---|---|---|---|
| SGAB | 3.84 | 2.70 | 5.47 | 3.18 | 2.23 | 4.17 |
| SGAFB | 1.72 | 1.51 | 1.78 | 13.30 | 10.32 | 16.28 |
| SGAPB | ||||||
| GLM | 1.34 | 1.23 | 1.44 | 14.34 | 11.26 | 17.34 |
| QR | 1.25 | 1.16 | 1.34 | 13.96 | 10.87 | 17.04 |
| RF | 1.81 | 1.62 | 1.88 | 13.45 | 10.87 | 15.89 |
| BART | 1.65 | 1.50 | 1.81 | 13.01 | 10.12 | 16.10 |
| GBM | 1.72 | 1.61 | 1.93 | 13.87 | 10.77 | 16.83 |
Abbreviations: GLM = generalized linear model; QR = quantile regression; RF = random forest; BART = Bayesian additive regression trees; GBM = generalized boosted models