Increased risk of maternal and neonatal complications in hormone replacement therapy cycles in frozen embryo transfer

Table 1 The baseline characteristics of all participants

	NC N = 4727	HRT N = 1642	OI N = 517	p-value
Maternal age (year)	30.8 ± 4.0	30.5 ± 4.1	30.9 ± 4.1	0.109
BMI (kg/m²)	22.5 ± 3.2^a,b	23.2 ± 3.4	22.8 ± 3.3	< 0.001^*
Indications for IVF
Tubal factor	2960 (62.6)	1025 (62.4)	325 (62.9)	0.981
Male factor	1056 (22.3)	356 (21.7)	114 (22.1)	0.856
Combined factors	566 (12.0)	201 (12.2)	60 (11.6)	0.919
Others	145 (3.1)	60 (3.7)	18 (3.5)	0.486
Irregular menstruation, n (%)	267 (5.6)^a,b	359 (21.9)	112 (21.7)	< 0.001^*
Donor sperm using, n (%)	441 (9.3)	131 (8.0)	38 (7.4)	0.115
FET cycle number	1.2 ± 0.5^a,b	1.3 ± 0.6^c	1.6 ± 0.8	< 0.001^*
No.of transferred embryos, n (%)
= 1	4138 (87.5)	1455 (88.6)	453 (87.6)	0.516
≥ 2	589 (12.5)	187 (11.4)	64 (12.4)	0.516
Vanishing twin gestation^d, n (%)	143 (3.0)	53 (3.2)	13 (2.5)	0.710
PFG (mmol/L)	5.2 ± 0.5^b	5.2 ± 0.5^c	5.3 ± 0.5	0.002^*
Systolic pressure (mmHg)	119.5 ± 11.8^a,b	120.8 ± 11.6	120.7 ± 11.9	< 0.001^*
Diastolic pressure (mmHg)	71.7 ± 8.7	72.4 ± 8.6	73.3 ± 8.8	< 0.001^*
Endometrial thickness (mm)	10.0 ± 1.6^a,b	9.5 ± 1.5^c	9.3 ± 1.7	< 0.001^*
AFC	14.9 ± 5.9^a	15.6 ± 6.6	15.3 ± 6.0	< 0.001^*
Testosterone level (ng/dL)	24.4 ± 11.7^a,b	26.0 ± 11.9	25.6 ± 12.5	< 0.001^*
AMH^e (ng/mL)	4.7 ± 3.7^a	5.3 ± 3.6^c	5.0 ± 3.5	< 0.001^*

NC natural cycle, HRT hormone replacement therapy, OI ovulation induction, BMI body mass index, FET frozen embryo transfer, PFG preconceptional fasting glucose, AFC Antral follicle count, AMH anti-müllerian hormone
*There were significant differences among the three groups
^aThere were significant differences between NC and HRT group
^bThere were significant differences between NC and OI group
^cThere were significant differences between HRT and OI group
^d5 of the patients underwent selective reduction of triplet or quadruplet pregnancy. 7 of the patients were of triplet pregnancy yet lost two fetuses spontaneously during early pregnancy
^eThere were data missing in AMH, including 430 in NC group and 122 in HRT group and 39 in OI group

ISSN: 1477-7827