The effects of different endometrial preparation regimens on pregnancy outcomes in frozen-thawed embryo transfer cycles: a prospective randomized controlled study

Figures & data

Figure 1. Flow diagram.

Table 1. General characteristics of the two groups.

	NC (Group A)	HRT (Group B)	P
No. of cycles	178	206
Age at freeze (y)	30.35 ± 4.32	30.49 ± 4.09	0.751
Age in study (y)	31.27 ± 4.40	31.24 ± 4.27	0.943
BMI (kg/m^2)	20.63 ± 2.41	20.92 ± 2.56	0.261
Duration of infertility (y)	3.00 [2.00, 6.00]	4.00 [2.00, 6.00]	0.209
No. of prior IVF attempts, n (%)			0.993
1	166 (93.26%)	192 (93.20%)
2	11 (6.18%)	13 (6.31%)
3	1 (0.56%)	1 (0.49%)
Prior fresh cycle pregnancy rate (%)	20.22% (36/178)	13.59% (28/206)	0.099
Infertility, n (%)			0.559
Primary	90 (50.56%)	98 (47.57%)
Secondary	88 (49.44%)	108 (52.43%)
Infertility factors, n (%)			0.455
Tubal factor	84 (47.19%)	112 (54.37%)
Endometriosis	2 (1.12%)	1 (0.49%)
Ovulation factor	2 (1.12%)	0
Multiple factor	7 (3.93%)	10 (4.85%)
Male factor	41 (23.03%)	39 (18.93%)
Male and female factors	35 (19.66%)	37 (17.96%)
Unexplained	7 (3.93%)	7 (3.40%)
Basal FSH (IU/L)	7.35 [6.36, 8.79]	7.52 [6.56, 8.77]	0.486
Basal LH (IU/L)	4.38 [3.20, 5.53]	4.71 [3.41, 6.85]	0.026
Basal E2 (pg/mL)	38.44 [26.96, 55.46]	40.82 [28.74, 57.00]	0.577
Basal T (pg/ml)	1.19 [0.79, 1.67]	1.32 [0.97, 1.72]	0.028
Basal PRL (pg/ml)	13.63 [9.47, 19.17]	13.30 [10.03, 21.56]	0.294
The quality of embryo, n (%)			0.992
With good quality embryo	96 (53.93%)	111 (53.88%)
Without good quality embryo	82 (46.07%)	95 (46.12%)
No. of embryos transferred, n (%) 1	8 (4.49%)	9 (4.37%)	0.777
2	80 (44.94%)	100 (48.54%)
3	90 (50.56%)	97 (47.09%)
Type of embryos transferred, n(%)			0.647
cleavage stage embryo	150 (84.27%)	170 (82.52%)
blastocyst	28 (15.73%)	36 (17.48%)
Endometrial thickness on hCG day, mm	10.75 [9.00, 12.00]	9.00 [8.00, 9.70]	<0.001

Note: Data are presented as mean ± SD, median (interquartile range), or number (%). BMI = body mass index; E₂: estradiol; T: testosterone; PRL: prolactin.

Table 2. Comparison of clinical outcomes between the two groups.

	NC (Group A)	HRT (Group B)	OR(95%CI)	P
Live birth rate	37.6% (67/178)	30.1% (62/206)	1.40 (0.92–2.14)	0.119
Clinical pregnancy rate	45.5% (81/178)	41.7% (86/206)	1.17 (0.78–1.75)	0.459
Implantation rate	24.9% (109/438)	22.3% (111/497)	1.15 (0.85–1.56)	0.359
Multiple pregnancy rate	32.1% (26/81)	27.9% (24/86)	1.22 (0.63–2.37)	0.554
Early miscarriage rate	11.1% (9/81)	15.1% (13/86)	0.70 (0.28–1.74)	0.444
late miscarriage rate	3.7% (3/81)	4.7% (4/86)	0.79 (0.17–3.64)	1.000
Miscarriage rate	14.8% (12/81)	19.8% (17/86)	0.71 (0.31–1.59)	0.398
Ectopic pregnancy rate	2.5% (2/81)	5.8% (5/86)	0.41 (0.07–2.18)	0.445
Cesarean delivery rate	64.2% (52/81)	50.0% (43/86)	1.79 (0.96–3.34)	0.064
Preterm birth rate	17.9% (12/67)	14.5% (9/62)	1.29 (0.50–3.30)	0.602
Low birth weigh rate	16.4% (11/67)	16.1% (10/62)	1.02 (0.40–2.60)	0.965

Note: Outcome data are presented as the % (n/N).

Table 3. Subgroup analysis of pregnancy outcomes between the two groups.

	With good quality embryo			Without good quality embryo			The blastocyst transferred			The cleavage stage embryos transferred
	NC	HRT	P	NC	HRT	P	NC	HRT	P	NC	HRT	P
Live birth rate	40.6%(39/96)	33.3%(37/111)	0.278	34.1%(28/82)	26.3%(25/95)	0.257	50.0%(14/28)	44.4%(16/36)	0.659	35.3%(53/150)	27.1%(46/170)	0.110
Clinical pregnancy rate	50.0%(48/96)	44.1%(49/111)	0.400	40.2%(33/82)	38.9%(37/95)	0.860	57.1%(16/28)	52.8%(19/36)	0.728	43.3%(65/150)	39.4%(67/170)	0.477
Implantation rate	27.7%(67/242)	23.6%(65/276)	0.281	21.4%(42/196)	20.8%(46/221)	0.878	34.5%(19/55)	39.1%(27/69)	0.600	23.5%(90/383)	19.6%(84/428)	0.180
Early miscarriage rate	14.6%(7/48)	14.3%(7/49)	0.967	6.1%(2/33)	16.2%(6/37)	0.266	6.3%(1/16)	15.8%(3/19)	0.608	12.3%(8/65)	14.9%(10/67)	0.661
late miscarriage rate	–	–	–	–	–	–	6.3%(1/16)	–	–	3.1%(2/65)	6.0%(4/67)	0.680
Ectopic pregnancy rate	2.1%(1/48)	6.1%(3/49)	0.617	3.0%(1/33)	5.4%(2/37)	1.000	–	–	–	3.1%(2/65)	7.5%(5/67)	0.441
Preterm birth rate	20.5%(8/39)	16.2%(6/37)	0.629	14.3%(4/28)	12.0%(3/25)	1.000	7.1%(1/14)	25.0%(4/16)	0.336	20.8%(11/53)	10.9%(5/46)	0.183
Low birth weight rate	20.5%(8/39)	21.6%(8/37)	0.906	10.7%(3/28)	8.0%(2/25)	1.000	14.3%(2/14)	25.0%(4/16)	0.657	17.0%(9/53)	13.0%(6/46)	0.586

Note: Outcome data are presented as % (n/N).

Table 4. Subgroup analysis of pregnancy outcomes between the two groups.

	Endometrial thickness <10mm			Endometrial thickness ≥10mm
	NC	HRT	P	NC	HRT	P
Live birth rate	32.3%(20/62)	26.3%(41/156)	0.375	40.5%(47/116)	42.0%(21/50)	0.859
Clinical pregnancy rate	41.9%(26/62)	39.7%(62/156)	0.766	47.4%(55/116)	48.0%(24/50)	0.945
Implantation rate	21.7%(34/157)	21.2%(79/373)	0.903	26.7%(75/281)	25.8%(32/124)	0.852
Early miscarriage rate	11.5%(3/26)	17.7%(11/62)	0.543	10.9%(6/55)	8.3%(2/24)	1.000
late miscarriage rate	3.8%(1/26)	6.5%(4/62)	1.000	3.6%(2/55)	–	–
Ectopic pregnancy rate	3.8%(1/26)	6.5%(4/62)	1.000	1.8%(1/55)	4.2%(1/24)	1.000
Preterm birth rate	15.0%(3/20)	14.6%(6/41)	1.000	19.1%(9/47)	14.3%(3/21)	0.742
Low birth weight rate	15.0%(3/20)	14.6%(6/41)	1.000	17.0%(8/47)	19.0%(4/21)	1.000

Note: Outcome data are presented as % (n/N).