Table 1.

Maternal and perinatal characteristics according to the treatment modality for infertility

Variable	Cryopreserved ET		Natural pregnancy
	HRT cycle	Ovulatory cycle
Number of patients	406	117	162
Birthweight (g)	3133.0 ± 374.6a,c	2996.9 ± 304.9b	3040.9 ± 354.8d
Age at delivery	36.2 ± 3.4a	35.6 ± 3.4c	34.2 ± 3.7b,d
Gestational age (days)	276.0 ± 8.8	274.8 ± 7.3	275.9 ± 7.9
Number of primiparous women (%)	290 (71.4)	86 (73.5)	119 (73.5)
Maternal BMI	20.8 ± 2.8	20.4 ± 2.2	20.4 ± 2.3

BMI, body mass index; ET, embryo transfer; HRT, hormone replacement therapy.

Values are expressed as the mean ± standard deviation.

a vs b, P < .01; c vs d, P < .05.