Perinatal Risks Associated with Early Vanishing Twin Syndrome following Transfer of Cleavage- or Blastocyst-Stage Embryos

Table 5

Low birth weight and multiple logistic regression to account for confounding variables.

LBW	Standard error	Adjusted OR; (95% CI)	P
Age (<35 versus ≥35 years)	0.59	1.16 (0.43–3.14)	0.77
Duration of ovarian stimulation (<9 versus ≥9 days)	1.25	1.24 (0.17–8.96)	0.83
Gonadotropin dose (<2000 versus ≥2000 IU)	0.76	0.81 (0.13–5.04)	0.82
Peak E2 level (<2000 versus ≥2000 pg/Ml)	0.30	0.86 (0.44–1.69)	0.66
Total number of oocytes (<10 versus ≥10)	0.20	0.93 (0.18–4.13)	0.77
Blastocyst-stage ET (yes versus no)	0.11	0.85 (0.66–1.99)	0.20

LBW: low birth weight; E₂: estradiol; ET: embryo transfer.