TABLE 1.

Baseline maternal demographic and clinical characteristics: singleton and twin autologous, singleton, and twin egg donor gestations.

Variable	Singleton birth						Twin birth
	Autologous eggs			Donor eggs			Autologous eggs			Donor eggs
	Fresh (n = 7,453)	Cryopreserved (n = 1,052)	P value	Fresh (n = 643)	Cryopreserved (n = 269)	P value	Fresh (n = 5,196)	Cryopreserved (n = 540)	P value	Fresh (n = 684)	Cryopreserved (n = 100)	P value
Age (y), mean ± SD	35.28 ± 4.08	35.01 ± 3.88	.04	41.78 ± 4.35	42.00 ± 5.04	.53	34.51 ± 3.91	34.61 ± 3.90	.58	41.08 ± 4.73	42.72 ± 4.26	.001
Gravida ≥1, %	53.70	32.89	<.0001	54.90	33.83	<.0001	28.43	22.96	.009	27.92	16.00	.01
Parity 0, %	64.62	41.06	<.0001	69.83	45.72	<.0001	33.64	27.22	.003	34.80	21.00	.001
BMI (kg/m²), %
<18.5	1.02	0.95	NA	0.62	0.37	NA	1.33	0.74	NA	0.88	2.00	NA
18.5–24.9	24.37	18.44		23.17	20.07		24.25	23.52		19.44	18.00
25–25.9	8.96	9.32		7.31	10.78		8.18	7.22		7.31	6.00
>30	6.24	5.70		4.67	2.97		6.62	5.19		2.63	4.00
Missing	59.41	65.59		64.23	65.80		59.62	63.33		69.74	70.00
Race/ethnicity, %
White	84.74	84.32	.22	87.09	90.71	.52	85.16	82.96	<.0001	91.52	78.00	<.0001
Black	3.02	4.18		2.18	2.60		2.52	5.56		2.05	6.00
Hispanic	3.37	3.61		3.42	2.60		3.87	5.56		1.46	2.00
Native American	1.05	0.67		0.78	0.37		1.23	1.30		0.88	0.00
Asian/Pacific Islander	7.74	7.22		6.07	3.72		7.10	4.26		3.51	14.00
Unknown	0.08	0.00		0.47	0.00		0.12	0.37		0.58	0.00
Chronic hypertension, %	1.27	2.00	.06	2.80	1.86	.49	1.66	1.11	.47	4.39	4.00	1.00
Pregestational diabetes, %	0.97	0.95	.96	0.62	1.49	.20	0.81	0.37	.43	0.58	2.00	.17
Infertility diagnosis, %
Tubal	8.24	8.65	.0004	0.93	1.86	.0003	6.97	10.93	.003	0.58	2.00	.10
Ovulation	8.06	9.22		2.33	7.43		9.16	10.74		4.39	8.00
Diminished ovarian reserve	3.74	0.95		41.68	31.97		3.23	1.11		39.47	26.00
Endometriosis	4.33	4.09		1.24	0.74		4.35	4.07		2.05	2.00
Uterine	0.99	1.33		0.31	1.12		1.12	0.93		0.29	0.00
Male only	24.47	24.52		1.87	0.74		23.60	25.17		4.68	4.00
Other	10.08	8.75		19.44	28.25		9.45	10.74		22.81	32.00
Unknown	23.68	24.05		5.44	7.06		25.87	23.52		6.73	6.00
Multiple female without male	5.18	6.75		11.66	9.67		4.85	3.70		10.23	14.00
Multiple female + male	11.22	11.69		15.09	11.15		11.41	9.07		8.77	6.00
Embryos transferred	2.23 ± 1.03	1.98 ± 0.79	<.01	1.89 ± 0.46	1.94 ± 0.72	.25	2.42 ± 0.84	2.43 ± 0.92	.65	2.07 ± 0.30	2.28 ± 0.57	<.01
First ET, %	50.82	13.69		39.81	7.06		51.14	10.19		38.89	4.00

Note: NA = over 50% of data are missing.

Sites. Embryo cryopreservation and preeclampsia risk. Fertil Steril 2017.