In our retrospective study, 12451 tubal infertile patients who underwent IVF/ICSI-ET at the Reproductive Center of The First Affiliated Hospital of Zhengzhou University between January 2014 and August 2019 were included and 8462 of them meet our acceptance criteria. There were 1747 patients with hydrosalpinx detected by ultrasound or hysterosalpingography (HSG) and 6715 patients without hydrosalpinx. Of all 1747 hydrosalpinx patients, 811 patients with undetectable fluid under ultrasound were excluded. Laparoscopic surgery group was defined as Group A including 209 hydrosalpinx patients with history of laparoscopic surgery such as salpingectomy and proximal tubal occlusion/ligation. Aspiration group was defined as Group B including 727 hydrosalpinx patients with fluid can be detected under ultrasound yet without history of laparoscopic surgery. Control group was defined as Group C including 6715 tubal infertile patients without hydrosalpinx.
Hydrosalpinx patients who didn't get clinical pregnant after ultrasonic-guided aspiration and had subsequent freeze-thaw embryo transfer cycles till December 2020 were included in the follow-up research. Subsequent laparoscopic surgery group was defined as Group B1 including 86 hydrosalpinx patients who received subsequent laparoscopic surgery treatment. Hysteroscopic occlusion group was defined as Group B2 including 41 hydrosalpinx patients who received subsequent hysteroscopic occlusion treatment. No treatment group was defined as Group B3 including 138 hydrosalpinx patients who received neither subsequent laparoscopic surgery treatment nor hysteroscopic occlusion treatment.
Inclusion criteria and exclusion criteria
The inclusion criteria were as follows: (1) tubal infertility women with age ≤40 years, BMI＜30 kg/m2, (2) at least one high-quality embryos transferred, (3) no history of intrauterine manipulation in the past 3 months, (4) not in the oocyte donation program, (5) not with preimplantation genetic diagnosis (PGD).
The exclusion criteria were as follows: (1) chromosomal anomaly and monogenic disease, (2) uterine malformations, (3) uterine anomaly or pathologies such as intrauterine adhesion, endometrial polyps or endometrial hyperplasia, (4) severe endometriosis (grade III and IV), (5) diabetes, hypertension, endocrinopathy, and autoimmune diseases, (6) no history of laparoscopic surgery, (7) undetectable fluid under ultrasound, (8) no subsequent cycle after aspiration due to pregnancy or personal reason.
The primary outcome measures of this study were LBR and CLBR while the secondary outcome measures were clinical pregnancy rate (CPR), cumulative clinical pregnancy rate (CCPR), implantation rate, multiple pregnancy rate, miscarriage rate, and ectopic pregnancy rate. LBR was calculated as the ratio of the number of live-born events divided by the number of transferred cycles. CLBR was calculated as the ratio of the number of patients whose freeze-thaw embryo transfer cycles following these studied fresh cycles had live-born events till December 2020 divided by the number of included patients. Clinical pregnancy was defined as at least one intrauterine gestational sac detected by ultrasound 5 or 6 weeks after embryo transfer. The cumulative clinical pregnancy was defined as at least one intrauterine gestational sac detected by ultrasound 5 or 6 weeks after all freeze-thaw embryo transfer following this studied fresh cycle till December 2020.
Controlled ovarian hyperstimulation protocols were determined according to each patient's characteristics (age, body mass index [BMI], antral follicle count [AFC], and AMH.  We regularly monitored follicle growth by trans-vaginal ultrasound and the serum estradiol, progesterone and LH levels during the cycle. When at least one follicle had a mean diameter of more than 18 mm, Aizer 250 μg (Merck Serono, Italy) or hCG (Zhuhai Lizhu Medicine) 2,000 IU was given. Oocytes retrievals were done 36 h later, and subsequent fresh embryo transfers were performed on day 3 or 5. Progesterone (60 mg) was injected intramuscularly on the day of oocyte retrieval. Progesterone gel (Xenotong, Merck Sherano, Switzerland) and oral dydrogesterone [10 mg [Duphaston], Solvay Pharmaceuticals B.V., Veenendaal, The Netherlands] were given vaginally from the day of embryo transfer for luteal phase support.
Patients received laparoscopic surgery before fresh cycles or freeze-thaw embryo transfer cycles. Laparoscopic surgery mentioned here only included salpingectomy or proximal tubal occlusion/ligation. Salpingostomy or other surgery was excluded. Salpingectomy directly removes the fluid, while proximal tubal occlusion uses electrocoagulation or ligature suture to cut off the interstitial part and the isthmus of the fallopian tube to block the reflux of fluid into the uterine cavity.
Ultrasonic-guided aspiration was conducted during oocyte retrieval procedure in fresh cycles. Ultrasound puncture needle was used to remove the fluid in the fallopian tube away.
Hysteroscopic tubal occlusion was conducted before freeze-thaw embryo transfer cycles. Before the freeze-thaw embryo transfer cycles, the Esure intrauterine device was placed under the hysteroscope to block the fallopian tubes and block reflux.
Continuous data were presented as mean±SD(Standard Deviation). Difference comparison would be tested by One-way ANOVA, and LSD test or TamhaneT2 test were used to put up multiple comparisons. Qualitative variables were given in frequency. Differences among groups would be tested by Chi-Square test. To adjust the influence of potential confounders, logistic regression analyses were performed. All statistical analyses were performed using SPSS (version 22.0, IBM Corp., Armonk, NY, USA) software. Statistically significant difference was defined as P < 0.05. In logistic regression analyses, odds ratio (OR) and their 95% confidence intervals (95% CI) were calculated from the model’s coefficients and their standard deviations.