P-634 Safety of ART cycles with extremely high estradiol levels - A retrospective cohort study

Study question

Are IVF treatments with extremely high peak estradiol levels during ovarian hyperstimulation associated with higher complication rates?

Summary answer

Extremely high estradiol levels were not associated with higher major complication rates, but patients were more likely to seek medical care following retrieval.

What is known already

The freeze-all policy and the increasing popularity of social oocyte freezing, have led to an increase in gonadotropin doses and number of oocytes retrieved and, as a direct effect, higher estradiol levels. Studies reporting major ART complications (OHSS, bleeding, infection, torsion, thromboembolic events) are based on heterogeneous patient populations without stratification by oocyte number or estradiol levels, except for a single study reporting an association between peak estradiol levels and the risk of ovarian torsion. Extreme estradiol levels, are associated with larger ovaries, repeated ovarian punctures, and possibly a thrombogenic effect. Therefore, higher complication rates can be expected.

Study design, size, duration

A retrospective cohort study including patients from two large medical centers treated between 2019-2021.

Participants/materials, setting, methods

A study group (239 patients) with extremely high peak estradiol levels (>20,000 pmol/L on the day of ovulation induction, or > 15,000 pmol/L on the previous day) and a control group (208 patients) with normal range estradiol levels (3000-12000pmol/L), treated at two large units were included. Patients were surveyed about complaints and medical care related to ovum pick up (OPU), and medical files were reviewed. Complication rates and the need for medical assistance were compared.

Main results and the role of chance

Several differences between the study and control group were observed as a consequence of the study design: Mean age was 33.01±5.14 vs. 34.57±4.52 (p = 0.01), Mean peak estradiol levels was 26645.34±8592.56 vs.7229.750±2329.20 (p < 0.001), mean number of oocytes were 27.55±13.46 vs. 11.63±5.77 (p < 0.001) for the study and control group respectivly. More patients in the control group underwent fertility preservation. Mean FSH levels and total gonadotropin dosage were higher in the control group. Major complications [3 (1.25%) in the study group vs. 1 (0.96%) in the control group] were similar between groups (p = 0.62). In the study group Two patients were diagnosed with ovarian torsion (0.83%), and one (0.41%) with early severe OHSS as a result of a positive BhCG related to an undiagnosed pregnancy prior to OPU. All three were admitted (1.25%). In the control group one patient was diagnosed with PID requiring inpatient IV antibiotic treatment (0.48%). One more patient was admitted with severe abdominal pain following OPU, for a total of 2 admissions (0.96%) (p = 1). 33 patients (13.8%) in the study group and 10 (4.8%) in the control group sought medical care after OPU, mostly due to abdominal pain, without further workup or hospitalization (p = 0.001).

Limitations, reasons for caution

A retrospective study with possible recall bias. Major adverse events are rare in IVF and may not be fully captured in the study population.

Wider implications of the findings

Based on our results, extremely high estradiol levels during ovarian hyperstimulation were not associated with thromboembolic events, higher major complication or hospitalization rates, thus may be considered safe. Nevertheless, patients may be informed of possible higher rates of discomfort, mostly abdominal pain. Larger studies are warranted to confirm our results.

Trial registration number

0090-21-ASF

P-710 COVID-19 Vaccination and Infertility Treatment Outcomes

Study question

Is there an influence of mRNA COVID-19 vaccine on ovarian response and in vitro fertilization (IVF) treatment outcomes?

Summary answer

COVID-19 mRNA vaccine did not affect the ovarian response nor pregnancy rates in IVF treatment

What is known already

Studies demonstrated that infection with COVID-19 during pregnancy increased the risk of the development of severe disease and pregnancy complications.

A recent meta-analysis of international data showed a declining tendency to be vaccinated, possibly influenced by public concerns over safety of the vaccines. Specifically, concerns were raised about a possible detrimental effect on fertility and pregnancy outcomes due to similarity between syncytin-1, a human placental fusion protein, and the SARS-CoV-2 spike protein expressed after administration of the COVID-19 vaccine.

To date, only one retrospective analysis on 36 infertility patients has assessed the influence of COVID-19 vaccination on IVF treatment outcomes.

Study design, size, duration

A retrospective cohort study . The study included a total of 400 patients, 200 vaccinated women and 200 age matched non-vaccinated women, undergoing IVF treatments during January-April 2021.

Participants/materials, setting, methods

All vaccinated women aged 20-42 that underwent IVF treatment cycles between January 1, 2021 and April 31 2021 were included. All participants completed two doses of the BNT162b2 (Pfizer-BioNTech) vaccine at least two weeks before starting ovarian stimulation. The study group was matched by age to non-vaccinated patients that underwent IVF treatments during the same period. Patients with a positive COVID 19 test in the past were excluded.

Main results and the role of chance

Two hundred patients underwent oocyte retrieval 14-68 days after receiving COVID-19 vaccination. No difference was found between vaccinated and non-vaccinated patients in mean number of oocytes retrieved per cycle (10.63 vs 10.72, p = 0.93). Among 128 vaccinated patients and 133 non-vaccinated patients that underwent fresh embryos transfers, no difference was demonstrated in clinical pregnancy rates (32.8% vs. 33.1%, p-value=0.96), 42 and 44 pregnancies respectively. The fertilization rates and mean number of cryopreserved embryos were similar between the two groups in freeze all cycles (55.43% vs. 54.29%, p-value=0.73), (3.59 vs. 3.28, p-value=0.80). Among vaccinated patients and non-vaccinated patients that underwent fresh embryos transfers, no difference was demonstrated in the fertilization rate (64.81% vs. 61.98%, p = 0.51), and transferred embryos quality. Regression models applied demonstrated no effect of the vaccine on oocyte yields and pregnancy rates.

Limitations, reasons for caution

Limitations include retrospective nature and different treatment protocols.

Additional limitation is the lack of information about vaccination status of the partners. One would assume that if unbalanced, the proportion of vaccinated males would be higher in the study group as partners tend to choose similarly in regard to vaccine administration.

Wider implications of the findings

Women should consider vaccination prior to their attempts to conceive via IVF treatments.

Trial registration number

ASF-0094-21

O-140 The impact of past COVID-19 infection on pregnancy rates in frozen embryo transfer cycles

Study question

What is the effect of COVID-19 infection on pregnancy rates in frozen embryo transfer (FET) cycles?

Summary answer

Past COVID-19 infection decreased pregnancy rates in FET cycles, especially in patients with recent infection.

What is known already

ACE2 and TMPRSS2 are expressed in the endometrium, potentially enabling SARS-COV-2 viral invasion of the cells. Unlike with bacterial infections, the effect of viral infections in general on implantation and pregnancy rates is unclear. Some evidence suggests that early embryonic and trophoblastic infection, may result in impaired implantation or placentation. A recently published study including both recovered and vaccinated patients did not find an effect of COVID-19 immunity on FET cycle outcomes. The study did not stratify by time from infection thus the immediate consequences of infection on pregnancy rates could not be properly evaluated.

Study design, size, duration

A retrospective cohort study, including 41 COVID-19 recovered women, aged 20-42 years that underwent FET cycles, and 41 controls between January 1, and June 31, 2021, at a large IVF unit.

Participants/materials, setting, methods

Embryos transferred were the product of fresh cycles performed prior to infection. Maximal time from infection to transfer was defined as one year. The study group was matched by age, number of embryos transferred and day of transfer, to unvaccinated patients, with no history of past infection that underwent FET cycles during the same period. Demographics and cycle characteristics were recorded. Clinical and ongoing pregnancy rates were compared, with further stratification by time from infection.

Main results and the role of chance

Clinical pregnancy rates were 29.3% and 48.8% for the recovered and control patients respectively (p = 0.070). Ongoing pregnancy rates were 26.6% vs. 43.4% (p = 0.093). Mean age at ovum pickup (30.72 vs. 30.69; p = 0.929) and at transfer (31.56 vs. 31.58; p = 0.966) was similar between groups, as were the demographic characteristics and previous retrievals and transfers. The predominant transfer protocol used was different between groups with higher rates of natural cycle (NC) protocol in the COVID group (61% vs. 33.3%; p = 0.013. All other cycle characteristics including endometrial width, number of embryos transferred, day of embryo transfer and embryo grade were similar. Stratification by time from COVID-19 infection to transfer into ≤60 and >60 days revealed a significant difference in pregnancy rates, with recovered women having lower pregnancy rates if infected in proximity to the transfer (20.7% vs. 55.2%; p = 0.006). In a logistic regression model, infection was a significant variable (p = 0.05, OR 0.325, 95% CI 0.106-0.998). Logistic regression applied on the subgroup of women infected in proximity to the transfer, further strengthened the univariate results, with COVID-19 infection remaining a significant parameter (p = 0.005, OR 0.072, 95% CI 0.012-0.450).

Limitations, reasons for caution

A retrospective study, with a limited sample size, but nevertheless our results showed significant differences. 

Wider implications of the findings

Further studies with larger groups are warranted to support these findings. Pending further information, in cases of FET cycles with limited numbers of embryos (advanced age, embryo donation, fertility preservation, embryos following sperm extraction), postponing embryo transfer for at least 60 days following recovery might be considered, if feasible.

Trial registration number

HMC-0010-21

O-141 IVF under COVID-19: treatment outcomes of fresh and frozen cycles

Study question

Does prior SARS-CoV-2 infection in women undergoing fertility treatments affect outcomes of fresh ART cycles? 

Summary answer

SARS-CoV-2 infection does not affect fresh ART treatment outcomes. A possible long term negative effect on oocyte yield should be further explored.

What is known already

There is evidence that the renin–angiotensin–aldosterone system (RAS) is involved in female reproductive processes such as folliculogenesis, steroidogenesis, oocyte maturation and ovulation. The existence of the ACE2 axis and ACE2 markers were confirmed in all stages of follicular maturation in the human ovary, including the granulosa cells and follicular fluid. A single previous study found no evidence that a history of asymptomatic or mild SARS-CoV-2 infection in females caused impairment of fresh ART treatment outcomes. 

Study design, size, duration

Retrospective cohort study, including all SARS-CoV-2 infected women that underwent fresh ART cycles within a year from infection (the first cycle post infection), between October 2020 and June 2021, matched to uninfected controls. 

Participants/materials, setting, methods

Retrospective cohort study, including all SARS-CoV-2 infected women that underwent fresh ART cycles within a year from infection (the first cycle post infection), between October 2020 and June 2021, matched to uninfected controls. 

Main results and the role of chance

121 infected patients and 121 controls that underwent fresh ART cycles were included. Oocyte yield (12.50 vs. 11.29; p = 0.169) and mature oocyte rate (77.71 vs. 81.76; p = 0.144) in all fresh cycles were similar between groups, as werefertilization rates, number of frozen embryos per cycle and clinical pregnancy rates (42.9% vs. 40.4%; p = 0.737) in fresh cycles with an embryo transfer. Stratification by time from COVID-19 infection by time from infection <90 day, 90-180 days and > 180 days revealed similar results with no difference in pregnancy rates. In a logistic regression model, COVID-19 infection did not affect pregnancy rates except for the small subgroup of patients who recovered more than 180 days prior to retrieval with a negative effect on oocyte yield (p = 0.018, Slope=-4.08, 95%CI 95% CI -0.7.41 – -0.75).

Limitations, reasons for caution

A retrospective study with data that was not uniformly generated under a study protocol, no antibody testing for the control group. 

Wider implications of the findings

The study findings suggest that COVID-19 infection does not affect treatment outcomes in fresh ART cycles, except for a possible long term negative effect on oocyte yield when retrieval occurs > 180 days post COVID-19 infection. Further studies are warranted in order to support these findings. 

Trial registration number

HMC-0010-21