Finally, a total of 1225 infertile couples who underwent 1225 FET cycles were performed between July 2013 and March 2015 were analyzed in this study. Additionally, according to the duration of post-thaw culture in FET cycles, these patients were allocated to three groups: the short culture(4–5 h) group (LAH group, n = 205; control group, n = 201), overnight culture(20–24 h) group (LAH group, n = 197; control group, n = 203), and blastocyst culture(44–48 h) group (LAH group, n = 210; control, n = 209 group), respectively.
1. Effect of LAH on clinical and perinatal outcomes of FET in the short culture group
During the study period, 406 patients who met the inclusion criteria were enrolled into the short
culture group, included 205 patients with LAH treatment (LAH group), 201 patients without LAH treatment (Control group), respectively. As shown in Table 1, the female age at thawing, body mass index (BMI), duration of infertility, type of infertility(primary), indications for infertility and the endometrial thickness on embryo transfer (ET)day were all similar between the two groups. In addition, the number of embryos transferred were also similar (1.83 versus1.79, P༞0.05).Consequently, no significant differences were found related to the implantation, clinical pregnancy and live birth rates between the two groups (28.0% versus 27.8%, 38.0% versus 36.8%, and 30.7% versus 30.3%, respectively, P༞0.05). Moreover, when the perinatal outcomes of two groups were compared, there was no significant difference in the gestational weeks (37.96 ± 2.23 versus 37.59 ± 2.35, P༞0.05), birth weight (2.70 ± 0.56 versus 2.82 ± 0.62, P༞0.05), as well as the preterm birth (15.4% versus 17.6%, P༞0.05), ectopic pregnancy (2.6% versus 1.4%, P༞0.05), and miscarriage rates (16.7% versus 16.2%, P༞0.05).
Table 1
Comparison of the characteristics of patients and clinical outcomes (short culture) between the LAH and control groups.
Variable
|
LAH group
|
Control group
|
P value
|
No. of patients(n)
|
205
|
201
|
-
|
Female age at thawing (y)
|
33.65 ± 5.01
|
33.72 ± 4.94
|
0.797
|
Body mass index(kg/m2)
|
21.38 ± 0.15
|
21.68 ± 0.13
|
0.765
|
Duration of infertility (y)
|
5.70 ± 3.90
|
5.45 ± 3.59
|
0.290
|
Type of infertility (primary) (%)
|
111/205 (54.1)
|
117/201 (58.2)
|
0.752
|
Indications for infertility
|
|
|
|
Ovarian disorders (%)
|
9(4.4)
|
8(4.0)
|
0.837
|
Endometriosis (%)
|
6(2.9)
|
13(6.5)
|
0.091
|
Tubal factor (%)
|
113(55.1)
|
124(61.7)
|
0.179
|
Male factor (%)
|
38(18.5)
|
30(14.9)
|
0.330
|
Mixed factor (%)
|
35(17.1)
|
23(11.4)
|
0.105
|
Unexplained (%)
|
4(2.0)
|
3(1.5)
|
1.000
|
Endometrial thickness on ET day (mm)
|
8.96 ± 1.90
|
9.45 ± 2.14
|
0.556
|
No. of embryos transferred
|
1.83 ± 0.36
|
1.79 ± 0.43
|
0.297
|
Implantation rate (%)
|
105/375 (28.0)
|
100/360(27.8)
|
0.853
|
Clinical pregnancy rate (%)
|
78/205(38.0)
|
74/201(36.8)
|
0.880
|
Live birth rate (%)
|
63/205(30.7)
|
61/201(30.3)
|
0.929
|
Gestational weeks(w)
|
37.96 ± 2.23
|
37.59 ± 2.35
|
0.838
|
Birth weight (Kg)
|
2.70 ± 0.56
|
2.82 ± 0.62
|
0.209
|
Preterm birth rate (༜37 weeks)
|
12/78(15.4)
|
13/74(17.6)
|
0.953
|
Ectopic pregnancy rate (%)
|
2/78(2.6)
|
1/74(1.4)
|
0.527
|
Miscarriage rate (%)
|
13/78(16.7)
|
12/74(16.2)
|
0.619
|
Values are shown as n/total (%) or means ± standard deviations (SD). LAH = laser-assisted hatching; ET = embryo transfer. No statistically differences were found between the two groups. |
2. Effect of LAH on clinical and perinatal outcomes of FET in the overnight culture group
The infertile couples’ characteristics and clinical outcomes of the overnight culture group are summarized in Table 2. The LAH group and control group did not differ significantly in the female age at thawing, BMI, duration of infertility, type of infertility, indications for infertility and the endometrial thickness on ET day. Similarly, no statistically differences were found regarding the number of embryos transferred, the implantation, clinical pregnancy and live birth rates (1.93 versus 1.84, 29.5% versus 29.1%, 40.1%versus 37.4%, 33.0%versus 30.5%, respectively, P༞0.05).
As to the perinatal outcomes, there was no significant difference in the gestational weeks (36.86 ± 2.28 versus 35.69 ± 2.95, P༞0.05), birth weight (2.73 ± 0.76 versus2.62 ± 0.52, P༞0.05), as well as the preterm birth (15.2% versus 17.1%, P༞0.05), ectopic pregnancy (3.8% versus 2.6%, P༞0.05), and miscarriage rates (13.9% versus 15.8%, P༞0.05).
Table 2
Comparison of the characteristics of patients and clinical outcomes (overnight culture) between LAH and control groups.
Variable
|
LAH group
|
Control group
|
P value
|
No. of patients(n)
|
197
|
203
|
-
|
Female age at thawing (y)
|
32.11 ± 4.61
|
32.37 ± 4.61
|
0.627
|
Body mass index(kg/m2)
|
21.18 ± 0.15
|
22.23 ± 0.21
|
0.762
|
Duration of infertility (y)
|
4.85 ± 3.08
|
4.79 ± 3.27
|
0.200
|
Type of infertility (primary) (%)
|
114/197(57.9)
|
107/203(52.7)
|
0.300
|
Indications
|
|
|
|
Ovarian disorders (%)
|
10(5.1)
|
4(2.0)
|
0.091
|
Endometriosis (%)
|
8(4.1)
|
5(2.5)
|
0.368
|
Tubal factor (%)
|
103(52.3)
|
123(60.6)
|
0.094
|
Male factor (%)
|
38(19.3)
|
28(13.8)
|
0.139
|
Mixed factor (%)
|
36(18.3)
|
40(19.7)
|
0.715
|
Unexplained (%)
|
2(1.0)
|
3(1.5)
|
1.000
|
Endometrial thickness on ET day (mm)
|
9.65 ± 2.16
|
9.95 ± 1.94
|
0.685
|
No. of embryos transferred
|
1.93 ± 0.26
|
1.84 ± 0.40
|
0.480
|
Implantation rate (%)
|
112/380(29.5)
|
109/374(29.1)
|
0.713
|
Clinical pregnancy rate (%)
|
79/197(40.1)
|
76/203(37.4)
|
0.637
|
Live birth rate (%)
|
65/197(33.0)
|
62/203(30.5)
|
0.290
|
Gestational weeks(w)
|
36.86 ± 2.28
|
35.69 ± 2.95
|
0.868
|
Birth weight (Kg)
|
2.73 ± 0.76
|
2.62 ± 0.52
|
0.409
|
Preterm birth (%)
|
12/79(15.2)
|
13/76(17.1)
|
0.856
|
Ectopic pregnancy rate (%)
|
3/79(3.8)
|
2/76(2.6)
|
0.687
|
Miscarriage rate (%)
|
11/79(13.9)
|
12/76 (15.8)
|
0.538
|
Values are shown as n/total (%) or means ± standard deviations (SD). LAH = laser-assisted hatching; ET = embryo transfer. No statistically differences were found between the two groups. |
3. Effect of LAH on clinical and perinatal outcome of FET in blastocyst culture group.
As displayed in Table 3, the characteristics of patients and clinical outcomes (blastocyst culture) between LAH and control groups were compared, no significant differences were observed between the two groups in female age at thawing, BMI, duration of infertility, type of infertility, indications for infertility and the endometrial thickness on ET day. Consequently, the two groups did not differ significantly in the number of embryos transferred, the implantation, clinical pregnancy and live birth rates between the two groups (1.75 ± 0.42 versus 1.69 ± 0.51, 56.3% versus 59.3%, 68.6% versus 66.5%, and55.7% versus56.5%, respectively, P༞0.05).Furthermore, there were also no significant difference in the gestational weeks (38.68 ± 2.76 versus 36.95 ± 2.59, P༞0.05), birth weight (2.78 ± 0.74 versus 2.72 ± 0.59, P༞0.05), as well as the preterm birth (8.3% versus 11.5%, P༞0.05), ectopic pregnancy (2.8% versus 2.2%, P༞0.05), and miscarriage rates (16.0% versus 12.9%, P༞0.05)
Table 3
Comparison of the characteristics of patients and clinical outcomes (blastocyst culture) between LAH and control groups.
Variable
|
AH group
|
Control group
|
P value
|
No. of patients(n)
|
210
|
209
|
-
|
Female age at thawing (y)
|
31.80 ± 3.79
|
30.56 ± 3.81
|
0.524
|
Body mass index BMI(kg/m2)
|
20.11 ± 0.25
|
21.23 ± 0.29
|
0.769
|
Duration of infertility (y)
|
4.32 ± 3.14
|
4.28 ± 2.60
|
0.223
|
Type of infertility (primary) (%)
|
100(47.6)
|
116(55.5)
|
0.106
|
Indications
|
|
|
|
Ovarian disorders (%)
|
18(8.6)
|
24(11.5)
|
0.321
|
Endometriosis (%)
|
7(3.3)
|
2(1.0)
|
0.175
|
Tubal factor (%)
|
133(63.3)
|
130(62.2)
|
0.811
|
Male factor (%)
|
25(11.9)
|
32(15.3)
|
0.309
|
Mixed factor (%)
|
24(11.4)
|
16(7.7)
|
0.189
|
Unexplained (%)
|
3(1.4)
|
5(2.4)
|
0.503
|
Endometrial thickness on ET day (mm)
|
10.45 ± 2.26
|
10.78 ± 2.32
|
0.475
|
No. of embryos transferred
|
1.75 ± 0.42
|
1.69 ± 0.51
|
0.166
|
Implantation rate (%)
|
207/368(56.3)
|
210/354(59.3)
|
0.701
|
Clinical pregnancy rate (%)
|
144/210 (68.6)
|
139/209 (66.5)
|
0.652
|
Live birth rate (%)
|
117/210(55.7)
|
118/209(56.5)
|
0.385
|
Gestational weeks(w)
|
38.68 ± 2.76
|
36.95 ± 2.59
|
0.764
|
Birth weight (Kg)
|
2.78 ± 0.74
|
2.72 ± 0.59
|
0.379
|
Preterm birth rate (%)
|
12/144(8.3)
|
16/139(11.5)
|
0.856
|
Ectopic pregnancy rate (%)
|
4/144 (2.8)
|
3/139 (2.2)
|
0.468
|
Miscarriage rate (%)
|
23/144(16.0)
|
18/139(12.9)
|
0.967
|
Values are shown as n/total (%) or means ± standard deviations (SD). LAH = laser-assisted hatching; ET = embryo transfer. No statistically differences were found between the two groups.