Table 2.
Poisson regression model identifying factors predictive of having supernumerary embryos
| Variable (referent) | Risk ratio (95% CI) | p value | Adjusted risk ratio (95% CI) | p value | |
|---|---|---|---|---|---|
| Age (< 35) | 35–37 | 0.80 (0.78–0.81) | < .001 | 0.98 (0.96–1.01) | .20 |
| 38–40 | 0.54 (0.53–0.56) | < .001 | 0.88 (0.85–0.91) | < .001 | |
| 41–42 | 0.28 (0.26–0.29) | < .001 | 0.60 (0.55–0.66) | < .001 | |
| > 42 | 0.11 (0.10–0.13) | < .001 | 0.30 (0.25–0.36) | < .001 | |
| BMI (18.5–24.9) | < 18.5 | 0.99 (0.93–1.05) | .634 | 0.99 (0.93–1.04) | .614 |
| 25.0–29.9 | 0.96 (0.94–0.98) | < .001 | 0.98 (0.96–1.00) | .081 | |
| > 30 | 0.95 (0.92–0.97) | < .001 | 0.96 (0.94–0.99) | .007 | |
| AMH (1.0–3.0) | < 1.0 | 0.48 (0.46–0.50) | < .001 | 0.88 (0.85–0.92) | < .001 |
| > 3.0 | 1.41 (1.38–1.44) | < .001 | 1.00 (0.98–1.03) | .737 | |
| Nulligravida | Gravida 1+ | 0.87 (0.85–0.88) | < .001 | 1.00 (0.98–1.02) | .831 |
| Prior fresh transfer (0) | 1 | 0.77 (0.75–0.78) | < .001 | 0.86 (0.84–0.89) | < .001 |
| 2 | 0.60 (0.58–0.63) | < .001 | 0.76 (0.72–0.81) | < .001 | |
| 3 | 0.49 (0.46–0.52) | < .001 | 0.75 (0.69–0.81) | < .001 | |
| 4+ | 0.35 (0.54–0.55) | < .001 | 0.72 (0.65–0.81) | < .001 | |
| Prior frozen transfer (0) | 1 | 1.05 (1.02–1.09) | < .001 | 1.23 (1.17–1.29) | < .001 |
| 2 | 1.22 (1.16–1.28) | < .001 | 1.35 (1.26–1.44) | < .001 | |
| 3 | 1.27 (1.17–1.38) | < .001 | 1.35 (1.22–1.50) | < .001 | |
| 4+ | 1.28 (1.15–1.42) | < .001 | 1.44 (1.25–1.65) | < .001 | |
| # eggs retrieved (1–6) | 7–9 | 2.92 (2.78–3.07) | < .001 | 2.35 (2.19–2.53) | < .001 |
| 10–13 | 4.25 (4.06–4.46) | < .001 | 2.93 (2.73–3.15) | < .001 | |
| 14–18 | 5.46 (5.21–5.71) | < .001 | 3.35 (3.12–3.60) | < .001 | |
| 19–35+ | 6.43 (6.15–6.72) | < .001 | 3.65 (3.39–3.93) | < .001 | |
| Sperm source (partner) | Donor | 0.95 (0.92–0.99) | .012 | 1.05 (1.01–1.10) | .022 |
| ICSI (no ICSI) | All mature | 0.93 (0.92–0.95) | < .001 | 0.97 (0.95–0.99) | .023 |
| Some mature | 1.18 (1.14–1.22) | < .001 | 0.94 (0.90–0.98) | .008 | |
| Day of transfer (5) | 2 | 0.24 (0.21–0.26) | < .001 | 0.84 (0.77–0.93) | .001 |
| 3 | 0.36 (0.35–0.37) | < .001 | 0.70 (0.66–0.74) | < .001 | |
| 4 | 0.45 (0.41–0.50) | < .001 | 0.71 (0.61–0.82) | < .001 | |
| 6 | 0.89 (0.86–0.92) | < .001 | 0.88 (0.84–0.92) | < .001 | |
| Blastocyst transfer | Cleavage transfer | 0.41 (0.40–0.42) | < .001 | 0.81 (0.78–0.85) | < .001 |
| Single embryo transfer | 2 | 0.86 (0.85–0.88) | < .001 | 0.89 (0.87–0.91) | < .001 |
| 3 | 0.35 (0.34–0.37) | < .001 | 0.59 (0.55–0.63) | < .001 | |
| 4 | 0.20 (0.18–0.23) | < .001 | 0.41 (0.33–0.51) | < .001 | |
| 5 | 0.18 (0.15–0.23) | < .001 | 0.52 (0.36–0.74) | < .001 | |
*all adjusted risk ratios with a p-value < .05 are provided in italics