Materials and methods
uterine anomalies, endometrial polyps, Mullerian anomalies, bicornuate, fibroids, insufficiency of corpus luteum, ovarian cyst
ENDOMETRIAL POLYPS, HYDROSALPINX, FIBROIDS, MISCARRIAGE, RECURRENT MISCARRIAGE, BLOOD, OVARIAN CYST, UTERUS
This retrospective cohort study in a single centre was carried out at the IVF centre of Acibadem Ataşehir Hospital between August 2022 and April 2023. A total of 181 true natural cycles vitrified–warmed FETs (tNC-FET) were evaluated. The Ethical Committee of Bezmialem University approved the protocol of our study (Approval no. 2023/165). Exclusion criteria were patients with cycle cancellation due to lack of a viable embryo or who had Mullerian anomalies not corrected by surgery, such as bicornuate, unicornuate, or didelphic uterus, those with a history of recurrent miscarriage, and those with a presence of hydrosalpinx. Those who had corrected uterine anomalies such as uterine septum, submucosal fibroids, or endometrial polyps were not excluded.The collected data consisted of demographic characteristics of the patients, including age at oocyte pick up (year), IVF indications (tubal, male, unexplained, diminishing ovarian reserve, ovulatory, mixed), serum LH concentration (IU/L) on the day of LH surge, serum progesterone concentration (ng/mL) on the day of LH surge and the day of embryo transfer, endometrial thickness (mm) on the day of embryo transfer, stage of transferred embryo (Day 3/blastocyst) and number of embryos transferred. Outcome parameters analysed are pregnancy rate, clinical pregnancy rate (CPR) (fetal heartbeat by transvaginal ultrasound), miscarriage rate (any clinical pregnancy lost before the 12All women underwent a transvaginal ultrasound scan on the second or third day of menstruation to confirm the absence of any ovarian cyst or CL. The second control was scheduled on the eighth day of the cycle to evaluate the emergence of the dominant follicle by transvaginal ultrasonography. Endocrine monitoring with serum LH and progesterone measurements was initiated everyday at 9 am once the leading follicle attained a mean diameter of approximately 15 mm. An increase of at least 180% compared to the previous serum LH level was taken as consistent with LH surge. FETs were performed four days after the LH rise for day three embryos and six days after the blastocyst stage. Blood samples for serum progesterone concentrations were collected on ET day at 9 am for all patients. 25 mg of SC progesterone (Prolutex; IBSA, Switzerland) per day was initiated at 11 am in patients with serum progesterone concentrations <10 ng/mL on ET day. The blood samples for pregnancy tests were collected 12 days after ET. Progesterone supplementation was discontinued if there was no pregnancy. We hypothesized that patients with serum progesterone concentrations <10 ng/mL in tNC-FET on the day of embryo transfer may have insufficiency of corpus luteum. We would like to continue SC progesterone until the luteo-placental shift (10th weeks of pregnancy). Therefore, progesterone supplementation at the same dose was continued until the 10th gestational week for viable pregnancies. Serum analysis and hormone measurement, vitrification and warming procedure, and ET were performed as described in our previous study (The data were analysed using SPSS Statistics for Windows, Version 26 (IBM Corp, Armonk, NY, USA). Data were reported as mean ± SD or number and percentage. The Pearson chi-squared test, Fisher’s exact and Fisher Freeman Halton tests were used to compare categorical variables. The Kolmogorov–Smirnov test was used to test the normal distribution of continuous variables. The homogeneity of variance was evaluated with Levene’s test. Student’s t-test was used to compare two independent groups regarding the means of normally distributed variables. The Mann–Whitney U-test was used to compare two independent groupsregardingf the means of non-normally distributed variables. P<0.05 was considered significant. As this is a retrospective study, no power analysis was performed prior to the study, and we included all women who underwent natural cycles FET during the period.