In 2018, of all initiated autologous fresh cycles (48,048), there were 92.8% cycles with an OPU (44,569), 49.3% cycles with a fresh ET (23,704), and after excluding 28.1% freeze-all cycles (13,520), there were 7399 clinical pregnancies and 5799 live births (16.8%).
Furthermore, ANZARD records multiple patient characteristics (Table 1). The number of live born singletons at term (gestational age of 37–41 weeks) with a normal birth weight (more than 2,500 grams) was 13,018, which was 80.2% of live born babies. The number of live born babies was 15,980, with a multiple birth rate of 3.2%. The number of live births was 15,475, thus calculating a LBR of 18.4% per initiated ART cycle. The number of clinical pregnancies was 19,514, giving a CPR of 23.2%. These initiated ART cycles were further differentiated into autologous (own eggs) cycles, either fresh or thaw, oocyte recipient, embryo recipient, oocyte donation, gamete intra-fallopian tube transfer, surrogacy arrangement cycles, commissioning or gestational carrier cycles. 8 In 2018, the number of initiated ART cycles was 84,064. The most recent ANZARD report published in 2020 reported 2018 data. 7 This data is publicly accessible and recorded through the following partnership’s, the National Perinatal Epidemiology and Statistics Unit of the University of New South Wales and the Fertility Society of Australia and New Zealand. ANZARD ART databaseĮvery ART and donor insemination cycle performed in our two countries is recorded in the Australian and New Zealand assisted reproduction database (ANZARD). Also, more than one baby can be born from one stimulated cycle and these births can be separated in time, often by years, which adds another layer of complexity. Due to a diversity of variations inherent in IVF treatment, including different age profiles of patients, use of pre-implantation genetic screening (PGS), utilisation of a ‘freeze-all’ strategy, treatments from one stimulated cycle being separated in time and increasing prevalence of IVF cycles that do not result in pregnancy outcomes (elective and medical oocyte freezing), coming up with an easily understood measure of IVF success that patients can relate to and make informed decisions about their treatment has proven elusive. Unfortunately, this seemingly straightforward statistic is not widely available and is difficult to estimate. Overall, it is probable that a chance of live birth of a healthy baby at term per treatment cycle initiated (stimulated cycle) is the most meaningful and easily understood measure of IVF success. The very definition of success in IVF may differ between patients and service providers. This often results in misleading outcomes promoted on clinical websites, where it becomes difficult to estimate an individual patient’s chance of success. Until recently, it was possible to select the most favourable outcomes and to use them for marketing purposes. This is due to many outcomes being reported and a variation in clinical practice between centres. The majority of reported outcomes may be called ‘surrogate outcomes’ and may be difficult for patients to interpret. 5 As such, some authors argue that it is not possible to have one single best outcome measure, but that a ‘set of clear, relevant, outcome indicators’ may be more meaningful in empowering patients to make informed choices about fertility treatment. SART report on ‘live births per intended egg retrieval (all embryos transferred) yet, HFEA report ‘cumulative live birth event per egg collection’, subtly excluding those who do not reach OPU stage. There have been international efforts to standardise reporting 4 however, data reported by the society for assisted reproductive technology (SART) in the US and the human fertilisation and embryology authority (HFEA) in the UK differ slightly. The need for rigor in reporting is important for patient education, scientific analysis and regulatory processes. Thus, changing the denominator can change the percentage.
3 These include, per treatment cycle initiated (fresh or thaw), per oocyte pick-up (OPU), per embryo transfer (ET), and these can change the statistic reported, given that not all stimulation cycles result in either OPU or ET.
If we consider these outcomes as numerators, then there are various denominators that relate to different parts of the ART cycle. 1 Furthermore, some studies call for more specific ART outcomes, such as birth emphasising a successful singleton at term. Outcomes of interest include clinical pregnancy rate (CPR), defined as ultrasound evidence of an intrauterine sac with or without a fetal heart, and live birth rate (LBR), defined as gestation more than 20 weeks or birth weight more than 400 grams, irrespective of multiple births. How best can we define success in assisted reproductive treatment (ART)? This seemingly simple question has many answers, depending on the type of measurement used.
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