Table 4 Neonatal outcomes of FETs stratified by the storage time

Birth sex ratio (male/female)

1.24

1.09

1.33

1.35

0.96

 < 0.001

 < 0.001

 < 0.001

 < 0.001

 male

5856

1458

475

170

171

 female

4730

1340

358

126

178

Singleton birth height(cm), mean ± SD

49.01 ± 2.70

49.02 ± 2.58

48.76 ± 2.86

49.39 ± 2.34

49.45 ± 1.91

0.973

0.673

1.082

1.258

Singleton birth weight(kg), mean ± SD

3.03 ± 0.60

2.99 ± 0.61

3.02 ± 0.64

3.04 ± 0.53

3.15 ± 0.38

0.786

0.983

0.819

0.914

Low birth weight (< 2500 g)

19.87(1335/6719)

19.46(380/1953)

18.12(114/629)

15.60(34/218)

15.71(33/210)

0.996

0.351

 < 0.001

 < 0.001

High birth weight (> 4000 g)

3.66(246/6719)

2.76(54/1953)

3.97(25/629)

1.83(4/218)

3.81(8/210)

 < 0.001

0.087

 < 0.001

0.068

Congenital anomalies

1.93(130/6719)

1.43(28/1953)

1.91(12/629)

1.83(4/218)

1.91(4/210)

 < 0.001

0.293

0.539

0.923