Characteristic
Expectant management (N=213) Embryo reduction (N=311)
p-value
Maternal age (y)* 33.2 ± 3.4 33.4 ± 3.9 NS
Height (cm)* 162.0 ± 5.4 161.4 ± 5.3 NS
BMI* 22.0 ± 3.4 21.7 ± 3.4 NS
Nulliparity 182 (85.4) 264 (84.9) NS
Prior preterm birth 2 (0.9) 8 (2.6) NS
Method of conception <0.001
Spontaneous 9 (4.2) 12 (3.9)
Ovarian hyperstimulation 89 (41.8) 43 (13.8)
In vitro fertilization 115 (54.0) 256 (82.3)