P–411 Does subcutaneous progesterone (SC-P) administration eliminate the necessity of serum progesterone level monitoring in frozen embryo transfer (FET) cycles?

Study question

Does SC-P provide similar ongoing pregnancy rates (OPRs) as intramuscular progesterone(IM-P) in hormone replacement therapy (HRT)-FET cycles and do serum progesterone (P) levels on FET day effect on pregnancy outcome? Summary answer: SC-P administration had similar OPR compared to IM-P in HRT-FET cycles. In SC-P group embryo transfer(ET) day P found to be insignificant factor for outcome.

What is known already

Different P routes can be used in HRT-FET cycles such as vaginal P, IM-P and recently SC-P. Only retrospective studies evaluated the comparison of SC-P with other routes in HRT-FET cycles. Here, we assessed prospectively whether SC-P is effective for HRT-FET cycles. Previous studies reported that serum P levels on ET day after vaginal P administration clinical outcomes were closely correlated. The correlation between serum P after IM-P administration and clinical outcomes were conflicting. In addition, there is lack of data on the serum P levels after SC-P administration. Serum P levels on ET day were evaluated in this study.

Study design, size, duration

This prospective cohort study was performed between July 1-October 31 2020, enrolled 224 patients scheduled for HRT-FET cycles with SC-P(25 mg twice daily) or IM-P(50 mg once daily). The route of P was decided according to the patient’s eligibility to hospital. First FET cycle was included after freeze-all cycles for each patients. Female age>35, PGT-A cycles, cleavage ET, >1 ET, patients with uterine pathology and hydrosalpinx, FET with surplus embryos, endometrial thickness<7mm were excluded.

Participants/materials, setting, methods

Female age ≤ 35 years old with a triple-layer endometrium >7 mm underwent transfer of single blastocysts after the first ET after freeze-all cycles. The indications for freeze-all were ovarian hyperstimuation syndrome and trigger day P level>1.5 ng/ml. 224 patients were eligible for study; 133 in SC-P group and 91 in IM-P group.The primary endpoint was the ongoing pregnancy rate (OPR) beyond pregnancy week 12.

Main results and the role of chance

The demographic, cycle, embryologic characteristics were similar between groups. The median circulating P levels on the day of ET were 19.92(15.195–27.255)ng/
ml and 21(16.48–28)ng/ml in the SC-P and IM-P groups,(p = 0.786). The clinical pregnancy rates [86/133(64.7%) vs 57/91(62.6%);p=0.757], miscarriage rates [21/86(24.4%) vs 10/57(17.5%) ;p=0.329], and OPR [65/133 (48.9%) vs 47/91(51.6%); p = 0.683] were comparable between the SC-P and IM-P. Binary logistic regression was performed for ongoing pregnancy as the dependent factor blastocyst morphology was found to be the only significant independent prognostic factor (p = 0.006), whereas the route of P was insignificant. In the SC-P and IM-P 
groups, the effect of ET day P levels were divided into quartiles(Q) to evaluate the effect on ongoing pregnancy. In SC-P group OPR were similar in four Q [Q1:33.3%(11/33),Q2:50%(17/34),Q3:60.6%(20/33),Q4:51.5%(17/33) (p = 0.1)].For IM-P group; Q1 had a significantly reduced OPR than Q2, Q3, Q4. [26.1%(6/23),65.2%(15/23),54.5%(12/22) and 60.9%(14/23), p = 0.031]. Logistic regression analysis for OP was performed separately in SC-P group and IM-P group. Although in SC-P group, ET day P levels was not found to be a significant factor, in IM-P ET day P level was found to be an independent factor for OP in IM-P group (Q1vs Q2+Q3+Q4; OR: 8,178 95% CI: [1.387–48.223] p:0.02).

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Limitations, reasons for caution

Although this study has the advantage of being prospective and in a homogenous study population, randomized controlled trials are warranted to evaluate the effectiveness of SC-P to other routes of P. Extrapolation to unselected populations of this study is needed.

Wider implications of the findings: Assignment of threshold of serum P on the day of ET for HRT-FET cycles to optimize outcomes is critical for every route of P. Regarding these results, individual luteal phase for HRT-FET cycles can improve IVF outcome.

Trial registration number

None

P–151 Correlation between the first euploid frozen-thawed blastocyst embryo transfer (FBT) and the subsequent euploid FBT outcome originating from the same cohort of oocytes

Study question

Does the outcome of the first euploid frozen-thawed blastocyst embryo transfer affect the subsequent euploid FBT originating from the same cohort of oocytes?

Summary answer

The clinical pregnancy rate and ongoing pregnancy rate of the subsequent FBT are higher if a clinical pregnancy was attained in the first euploid FBT.

What is known already

Numerous factors including patient, cycle and embryological characteristics affect the outcome of an IVF treatment cycle. There is no data available whether the outcome of euploid FBT has an impact on the outcome of the subsequent euploid FBT of embryos originating from the same cohort of retrieved oocytes.

Study design, size, duration

The study enrolled cycles preimplantation genetic test for aneuploidy (PGT-A) performed between January 2016 and July 2019 at the Bahceci Fulya IVF Center. A total of 1051 patients with single euploid FBT were evaluated and resulted live birth (n = 589, live birth rate (LBR): 56%(589/1051)), miscarriage (n = 100, miscarriage rate (MR): 14.5% (100/689)) and no clinical pregnancy (n = 362, 34,4%, (362/1051)). 159 FBT after the first single euploid FBT originating from the same cohort of oocytes were analyzed.

Participants/materials, setting, methods

Second euploid FBT cycle after first FBT with a clinical pregnancy were compared to frozen-thawed cycles after a without a pregnancy. Logistic regression analysis was utilized to adjust for potential confounders including female age, body mass index, embryo quality, day of embryo frozen, number previous failed attempt, number of previous miscarriage, endometrial thickness, outcome of the first euploid FBT.

Main results and the role of chance

The pregnancy outcome from the first euploid FBT in the study group was resulted live birth (25.1%, (40/159)), miscarriage (15.7%, (25/159)) and no clinical pregnancy (59.1%, (94/159). The pregnancy outcome of the subsequent euploid embryo transfer from the same oocyte cohort was clinical pregnancy rate (CPR): (67.3%, (107/159) ongoing pregnancy rate (OPR) (52.2% (83/159) and MR (22.4%, (24/107)). The CPR in the subsequent euploid FBT was 80% (52/65) among patients who achieved a clinical pregnancy in the first euploid FBT and 58.5% (55/94) of those who did not (p = 0.0045). The OPR in the subsequent euploid FBT was 64.6% (42/65) among patients who achieved a clinical pregnancy in first euploid FBT and 43.6% (41/94) of those who did not (p = 0.009). On a multivariate regression analysis, clinical pregnancy in the first euploid FBT was a significant independent predictor for a pregnancy in the subsequent FBT transfer (p = 0.003).

Limitations, reasons for caution

The limitation of the study is in the retrospective nature of the study. As the PGT-A strategy significantly decreases number of transferable embryos, the sample size of the study is limited.

Wider implications of the findings: Identifying predictive factors for the success of euploid FBT is important. These can help physicians while counseling patients regarding the outcome of the previous euploid FBT.

Trial registration number

NA