All study methods were approved by the Ethics Committee of Hubei Maternal and Child Health Hospital (2022IEC081) and were conducted in accordance with relevant guidelines and regulations. All subjects enrolled in the study gave written informed consent to participate.
HRT-FET cycles involving in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) performed at the reproductive center from January 2019 to December 2020 were collected. Inclusion criteria were (1) age ≤40 years; (2) endometrial thickness greater than 8 mm; (3) two blastocysts were transferred; Exclusion criteria included (1) uterine lesions and uterine malformations; (2) fibroids; (3) endometriosis; (4) hydrosalping; (5) chromosomal abnormalities. (6) history of thrombosis; (7) contraindication to estrogen. (8) Embryos that received PGTA. A total of 708 cycles met the above inclusion and exclusion criteria.
Endometrial preparation and grouping
If the B-ultrasound showed normal uterus and ovaries on day 3 of menstrual onset or withdrawal bleeding, the patient was started on Progynova 2 mg twice daily for 4 days, followed by Progynova 3 mg. twice daily for the next 4 days. days. He then had a B-ultrasound to show the thickness of the endometrium and adjusted the progynova dose and days of administration according to the thickness of the endometrium. Serum estrogen and progesterone levels were measured when the endometrial thickness exceeded 8 mm. Progesterone was injected if the progesterone level was <1.0 pg/ml. Five days later, two blastocysts were implanted into the uterus. Before blastocyst transfer, endometrial thickness was measured and estrogen and progesterone levels were measured. The 708 cycles were divided into Group A according to the quartile (P25) of serum estrogen levels on the day of endometrial transformation.1 (E2 < 157.5 pg/ml, 176 cycles), group A2 (157.5 pg/ml ≤ E2 < 206.4 pg/ml, 178 cycles), group A3 (206.4 pg/ml ≤ E2 < 302.3 pg/ml, 176 cycles) and Group AFour (E2 ≥ 302.3 pg/ml, 178 cycles). The 708 cycles were divided into Group B according to the quartile (P25) of serum estrogen levels on the day of freeze-thaw blastocyst transfer.1 (E2 < 147 pg/ml, 176 cycles), group B2 (147 pg/ml ≤ E2 < 200.4 pg/ml, 178 cycles), group B3 (200.4 pg/ml ≤ E2 < 323 pg/ml, 176 cycles) and group BFour (E2 ≥ 323 pg/ml, 178 cycles). Age, endometrial thickness on the day of endometrial transformation, endometrial thickness on the day of blastocyst transfer, days on progynova, progesterone levels on the day of blastocyst transfer, high-quality embryos transferred Clinical characteristics, including the number of cysts and pregnancy outcome, including clinical pregnancy rate, blastocyst implantation rate, multiple pregnancy rate, abortion rate, and live birth rate were compared between groups. The 708 cycles were divided into a clinical pregnancy group (n = 520) and a non-clinical pregnancy group (n = 188) according to different clinical outcomes. Estrogen levels on the day of endometrial transformation and the day of blastocyst transfer were compared between the two groups. Multivariate regression analysis of clinical pregnancy and correlation analysis between clinical pregnancy and serum E2 levels were performed.
According to the Gardner scoring system14, blastocysts with stage 3 or higher blastocyst cavity expansion, grade B or higher inner cell mass, and grade C or higher trophectoderm were subjected to cryopreservation. Vitrification and thawing were used for transferred blastocysts. Blastocyst cavity enlargement indicated survival of thawed blastocysts. These blastocysts were thawed 2 hours prior to blastocyst transfer. Laser drilling was performed on these blastocysts prior to embryo transfer. In this study, two blastocysts containing at least one high-quality blastocyst were transferred to each patient.In this study, according to the Gardner scoring system14blastocysts with blastocyst cavity expansion stage 3 or higher, inner cell mass grade B or higher, and trophectoderm grade B or higher were considered high-quality blastocysts.
Luteal phase support and pregnancy diagnosis
After blastocyst transfer, progesterone 60 mg was injected intramuscularly once daily. Patients received progynova as before blastocyst transfer. On days 14 and 18 after blastocyst transfer, blood β-hCG levels >5 mIU/ml indicated biochemical pregnancy. A B-ultrasound showing a gestational sac on day 28 after blastocyst transfer was considered clinical pregnancy. For the pregnant patient, luteal phase support lasted until her first 8-10 weeks. Abortion within 28 weeks of gestation was considered abortion.
All data were analyzed with SPSS 22.0 software. Measured data are expressed as mean ± standard deviation, t The test was used for comparison between groups. Count data are expressed as rates and χ2 The test was used for comparisons between groups and Fisher’s exact test was used for theoretical frequencies less than 5. A logistic regression equation was used for multivariate analysis and her ROC curve was used for correlation analysis between clinical pregnancies and serum E2 levels.Statistical significance is P.< 0.05.