Risk of perinatal outcomes associated with fetal reduction
| Perinatal outcome | Reduced to twin pregnancy v. unreduced triplet pregnancy | Reduced to singleton pregnancy v. unreduced twin pregnancy | ||||
|---|---|---|---|---|---|---|
| All births | ART only | All births | ART only | |||
| Crude rate ratio (95% CI) | Adjusted rate ratio* (95% CI) | Adjusted rate ratio† (95% CI) | Crude rate ratio (95% CI) | Adjusted rate ratio* (95% CI) | Adjusted rate ratio† (95% CI) | |
| Preterm (< 37 wk) | 0.62 (0.40–0.78) | 0.66 (0.54–0.80) | 0.68 (0.56–0.84) | 0.40 (0.25–0.65) | 0.40 (0.25–0.66) | 0.42 (0.23–0.77) |
| Very preterm (< 32 wk) | 0.37 (0.18–0.76) | 0.40 (0.20–0.78) | 0.92 (0.17–0.59) | 1.24 (0.58–2.65) | 1.36 (0.64–2.92) | 1.44 (0.53–3.89) |
| Low birth weight (< 2500 g) | 0.58 (0.47–0.72) | 0.59 (0.49–0.72) | 0.58 (0.46–0.72) | 0.50 (0.30–0.81) | 0.51 (0.32–0.82) | 0.39 (0.19–0.78) |
| Very low birth weight (< 1500 g) | 0.42 (0.21–0.82) | 0.43 (0.23–0.81) | 0.39 (0.22–0.67) | 1.07 (0.42–2.76) | 1.19 (0.45–3.04) | 0.94 (0.25–3.51) |
| Small for gestational age | 1.89 (1.09–3.28) | 2.14 (1.18–3.88) | 2.29 (1.20–4.39) | 1.07 (0.62–1.87) | 1.13 (0.65–1.93) | 0.68 (0.27–1.70) |
| 5-min Apgar score ≤ 7 | 0.58 (0.28–1.19) | 0.60 (0.28–1.30) | 0.37 (0.15–0.92) | 1.06 (0.50–2.25) | 1.16 (0.55–2.46) | 1.23 (0.51–2.94) |
| Serious neonatal morbidity or perinatal death | 0.50 (0.24–1.02) | 0.50 (0.24–1.07) | 0.35 (0.18–0.67) | 1.39 (0.65–2.95) | 1.57 (0.74–3.33) | 1.60 (0.64–3.98) |
Note: ART = assisted reproductive technology, CI = confidence interval.
↵* Adjusted for infant sex, maternal age, parity, pre-pregnancy weight, socioeconomic status and use of assisted reproductive technology.
↵† Adjusted for infant sex, maternal age, parity, pre-pregnancy weight and socioeconomic status.