Table 3.
Crude and adjusted ORs of ovarian stimulation protocols compared with natural cycle for pregnancy and neonatal outcomes.
| Outcomes | Crude OR (95% Cl) | P value | Adjusted OR (95% Cl)a | P value |
|---|---|---|---|---|
| PTD (<37 weeks) | ||||
| Natural cycle | Reference | Reference | ||
| Clomiphene alone | 1.35 (1.16 to 1.58) | <0.001 | 1.33 (1.13 to 1.58) | 0.001 |
| Clomiphene + gonadotropin | 1.33 (1.06 to 1.66) | 0.01 | 1.31 (1.03 to 1.66) | 0.03 |
| GnRH agonist | 1.39 (1.21 to 1.59) | <0.001 | 1.34 (1.13 to 1.58) | 0.001 |
| GnRH antagonist | 1.41 (1.21 to 1.65) | <0.001 | 1.37 (1.14 to 1.63) | 0.001 |
| VPTD (<32 weeks) | ||||
| Natural cycle | Reference | Reference | ||
| Clomiphene alone | 1.19 (0.83 to 1.71) | 0.34 | 1.16 (0.80 to 1.67) | 0.43 |
| Clomiphene + gonadotropin | 1.62 (1.06 to 2.48) | 0.03 | 1.61 (1.02 to 2.53) | 0.04 |
| GnRH agonist | 1.15 (0.81 to 1.63) | 0.45 | 1.13 (0.78 to 1.64) | 0.52 |
| GnRH antagonist | 1.30 (0.90 to 1.87) | 0.16 | 1.25 (0.85 to 1.83) | 0.26 |
| LBW (<2500 g) | ||||
| Natural cycle | Reference | Reference | ||
| Clomiphene alone | 1.63 (1.48 to 1.79) | <0.001 | 1.62 (1.46 to 1.79) | <0.001 |
| Clomiphene + gonadotropin | 1.67 (1.48 to 1.89) | <0.001 | 1.67 (1.45 to 1.91) | <0.001 |
| GnRH agonist | 1.44 (1.31 to 1.59) | <0.001 | 1.44 (1.29 to 1.59) | <0.001 |
| GnRH antagonist | 1.43 (1.27 to 1.61) | <0.001 | 1.42 (1.26 to 1.60) | <0.001 |
| VLBW (<1500 g) | ||||
| Natural cycle | Reference | Reference | ||
| Clomiphene alone | 1.75 (1.27 to 2.41) | 0.001 | 1.69 (1.23 to 2.31) | 0.001 |
| Clomiphene + gonadotropin | 2.44 (1.60 to 3.72) | <0.001 | 2.38 (1.52 to 3.72) | <0.001 |
| GnRH agonist | 1.47 (1.06 to 2.05) | 0.02 | 1.41 (0.999 to 1.98) | 0.051 |
| GnRH antagonist | 1.57 (1.06 to 2.30) | 0.02 | 1.47 (0.995 to 2.18) | 0.053 |
| SGAb | ||||
| Natural cycle | Reference | Reference | ||
| Clomiphene alone | 1.66 (1.48 to 1.87) | <0.001 | 1.64 (1.46 to 1.84) | <0.001 |
| Clomiphene + gonadotropin | 1.74 (1.50 to 2.02) | <0.001 | 1.71 (1.47 to 1.98) | <0.001 |
| GnRH agonist | 1.25 (1.07 to 1.46) | 0.004 | 1.23 (1.05 to 1.45) | 0.01 |
| GnRH antagonist | 1.29 (1.07 to 1.54) | 0.006 | 1.27 (1.06 to 1.52) | 0.01 |
| LGAb | ||||
| Natural cycle | Reference | Reference | ||
| Clomiphene alone | 0.90 (0.82 to 0.98) | 0.01 | 0.89 (0.80 to 0.99) | 0.03 |
| Clomiphene + gonadotropin | 0.86 (0.77 to 0.96) | 0.01 | 0.88 (0.78 to 0.998) | 0.046 |
| GnRH agonist | 0.92 (0.84 to 0.996) | 0.04 | 0.96 (0.88 to 1.05) | 0.35 |
| GnRH antagonist | 0.96 (0.87 to 1.07) | 0.46 | 0.98 (0.88 to 1.08) | 0.66 |
| CS | ||||
| Natural cycle | Reference | Reference | ||
| Clomiphene alone | 1.22 (1.11 to 1.34) | <0.001 | 1.18 (1.08 to 1.28) | <0.001 |
| Clomiphene + gonadotropin | 1.10 (0.99 to 1.22) | 0.08 | 1.13 (1.004 to 1.26) | 0.04 |
| GnRH agonist | 0.99 (0.90 to 1.09) | 0.82 | 1.04 (0.96 to 1.13) | 0.35 |
| GnRH antagonist | 1.07 (0.97 to 1.18) | 0.19 | 1.07 (0.98 to 1.18) | 0.14 |
aAdjusted for maternal age, infertility diagnosis, fertilization method, fetal sex and year.
bSGA was defined as being below the 10th percentile of the national reference. LGA was defined as being above the 10th percentile of the national reference.
CI, confidence interval; CS, cesarean section; LBW, low birth weight; LGA, large for gestational age; OR, odds ratio; PTD, preterm delivery; SGA, small for gestational age; VLBW, very low birth weight; VPTD, very preterm delivery.