Table 5.

Preterm Delivery and Low Birthweight in Singleton Live Births Following Fresh vs. Frozen Embryo Transfer in Oocyte Donor Recipients

Singletons N=8,768	Fresh Embryo Transfer	Frozen Embryo Transfer	OR (95% CI)	AOR (95% CI)*
Fullterm	76.6% (4,328/5,648)	75.7% (2,361/3,120)	Reference	Reference
Preterm Delivery (32 - 37 wks)	19.3% (1,091/5,648)	20.7% (646/3,120)	0.93 (0.83 - 1.03) p=0.16	0.96 (0.84 - 1.09) p=0.50
Very Preterm (<32 weeks)	4.1% (229/5,648)	3.6% (113/3,120)	1.08 (0.86 - 1.36) p=0.48	**
Overall LBW	11.5% (644/5,595)	11.3% (346/3,072)	1.03 (0.90 - 1.18) p=0.65	0.99 (0-82 - 1.18) p=0.87
Term LBWˆ (≥ 37 weeks, <2500 gms)	2.2% (93/4,286)	1.7% (39/2,325)	1.30 (0.89 - 1.89) p=0.17	1.41 (0.82 - 2.42) p=0.22
Preterm LBWˆ (<37 weeks, <2500 gm)	32.7% (352/1,078)	33.1% (211/638)	0.98 (0.80 - 1.21) p=0.87	0.94 (0.71 - 1.24) p=0.67

^*Adjusted for reporting year, patient age, parity, infertility diagnosis, number of embryos transferred, number of prior ART cycles, prior miscarriage, reduction in fetal heart, multiple pregnancy, implantation rate

^**For adjusted analysis, preterm and very preterm delivery combined

^ˆOnly subjects with recorded data for both gestational age and birthweight were included in analysis.