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Table 1 Maternal characteristics of pregnancies carried to delivery following FET with different endometrial preparation protocols

From: Perinatal outcomes of neonates born from different endometrial preparation protocols after frozen embryo transfer: a retrospective cohort study

 

NC (N = 1921)

OS (N = 360)

HRT (N = 1583)

p

No. (%)

No. (%)

No. (%)

Maternal socio-demographic characteristics

 Age of oocyte retrieval, Mean ± SD, years

31.25 ± 3.74

30.95 ± 3.81

30.73 ± 3.69

< 0.001

 Age of embryo transfer, Mean ± SD, years

31.43 ± 3.74

31.04 ± 3.78

30.96 ± 3.70

< 0.001

 Pre-gestational BMI, Mean ± SD, kg/m2

22.42 ± 3.02

22.55 ± 2.99

22.35 ± 3.24

0.216

 Residence

  Residents

1271 (66.16)

228 (63.33)

1057 (66.77)

0.731

  Immigrants

650 (33.84)

132 (36.67)

526 (33.23)

 

 Education attainment

  Primary school or lower

21 (1.09)

8 (2.22)

16 (1.01)

0.386

  Middle school

223 (11.61)

43 (11.94)

207 (13.08)

 

  High school

316 (16.45)

57 (15.83)

271 (17.12)

 

  Collage or above

1361 (70.85)

252 (70.00)

1089 (69.79)

 

 Occupation

  Employed

1339 (69.70)

219 (60.83)

1127 (71.19)

0.735

  Self-employed

400 (20.82)

108 (30.00)

297 (18.76)

 

  Unemployed

182 (9.47)

33 (9.17)

159 (10.04)

 

 Smoking during pregnancy

  No

1898 (98.80)

357 (99.17)

1571 (99.24)

0.187

  Yes

23 (1.20)

3 (0.83)

12 (0.76)

 

History of reproduction

 Parity

  No

1754 (91.83)

333 (92.50)

1475 (93.18)

0.132

  Yes

157 (8.17)

27 (7.50)

108 (6.82)

 

 Number of previous abortions

  0

1298 (67.57)

227 (63.06)

1093 (69.05)

0.147

  1–2

560 (29.15)

124 (34.44)

448 (28.30)

 

  ≥ 3

63 (3.28)

9 (2.50)

42 (2.65)

 

 Previous ectopic pregnancy

  No

1668 (86.83)

316 (87.78)

1378 (87.05)

0.837

  Yes

253 (13.17)

44 (12.22)

205 (12.95)

 

 Duration of infertility

  1–2

747 (38.89)

133 (36.94)

589 (37.21)

0.195

  3–4

592 (30.82)

133 (36.94)

532 (33.61)

 

  ≥ 5

582 (30.30)

94 (26.11)

462 (29.19)

 

 Primary infertility

  No

1104 (57.47)

207 (57.50)

924 (58.37)

0.954

  Yes

817 (42.53)

153 (42.50)

659 (41.63)

 

 Causes of infertility

  Tubal infertility

924 (48.10)

155 (43.06)

654 (41.31)

< 0.001

  Anovulatory

24 (1.25)

30 (8.33)

183 (11.56)

 

  Endometriosis

55 (2.86)

4 (1.11)

44 (2.78)

 

  Male-factor infertility

159 (8.28)

19 (5.28)

106 (6.70)

 

  Unexplained infertility

321 (16.71)

70 (19.44)

196 (12.38)

 

  Combined a

438 (22.80)

82 (22.78)

400 (25.27)

 
  1. FET frozen embryo transfer, NC natural cycles, OS ovarian stimulation, HRT hormonal replacement therapy, BMI body mass index
  2. aCombined was defined as two or more infertile causes mentioned above