Cumulative live birth rates following a ‘freeze-all’ strategy: a population-based study

Abstract

STUDY QUESTION What is the cumulative live birth rate following a ‘freeze-all’ strategy compared with a ‘fresh-transfer’ strategy? SUMMARY ANSWER The ‘freeze-all’ strategy resulted in a similar cumulative live birth rate as the ‘fresh-transfer’ strategy among high responders (>15 oocytes retrieved) but did not benefit normal (10–15 oocytes) and suboptimal responders (<10 oocytes). WHAT IS KNOWN ALREADY Frozen-thawed embryo transfer is associated with a decreased risk of adverse obstetric and perinatal outcomes compared with fresh embryo transfer. It is unclear whether the ‘freeze-all’ strategy should be offered to all women undergoing ART treatment. STUDY DESIGN, SIZE, DURATION A population-based retrospective cohort study using data collected by the Victorian Assisted Reproductive Treatment Authority. This study included 14 331 women undergoing their first stimulated ART cycle with at least one oocyte fertilised between 1 July 2009 and 30 June 2014 in Victoria, Australia. Demographic characteristics, type of ART procedures and resulting pregnancy and birth outcomes were recorded for the stimulated cycle and associated thaw cycles until 30 June 2016, or until a live birth was achieved, or until all embryos from the stimulated cycle had been used. PARTICIPANTS/MATERIALS, SETTING, METHODS Women were grouped by whether they had undergone the ‘freeze-all’ strategy ( n = 1028) where all embryos were cryopreserved for future transfer, or the ‘fresh-transfer’ strategy ( n = 13 303) where selected embryo(s) were transferred in the stimulated cycle, and remaining embryo(s) were cryopreserved for future use. A discrete-time survival model was used to evaluate the cumulative live birth rate following ‘freeze-all’ and ‘fresh-transfer’ strategy. MAIN RESULTS AND THE ROLE OF CHANCE A total of 1028 women undergoing ‘freeze-all’ strategy and 13 303 women undergoing ‘fresh-transfer’ strategy had 1788 and 22 334 embryo transfer cycles resulting in 452 and 5126 live births, respectively. Most women (61.3%) in the ‘freeze-all’ group had more than 15 oocytes retrieved in the stimulated cycle compared with 18.1% of women in the ‘fresh-transfer’ group ( P < 0.001). For high responders (>15 oocytes), the cumulative live birth rate in the ‘freeze-all’ group was similar to the ‘fresh-transfer’ group (56.8% vs. 56.2%, adjusted hazard ratio (AHR) 0.90, 95% CI 0.77–1.04). However, the likelihood of a live birth was lower in the ‘freeze-all’ group compared with the ‘fresh-transfer’ group among normal responders (10–15 oocytes) (33.2% vs. 46.3%, AHR 0.62, 95% CI 0.46–0.83) and suboptimal responders (<10 oocytes) (14.6% vs. 28.0%, AHR 0.67, 95% CI 0.14–1.01). During the minimum follow-up time of 2 years, 34.1%, 24.4% and 8.4% of suboptimal, normal and high responders, respectively, in th...

Hormone Replacement Versus Natural Cycle Protocols of Endometrial Preparation for Frozen Embryo Transfer

“…In 1983, the first successful pregnant of frozen embryo transfer (FET) was reported in humans, and FET technology has been widely applied in the clinic ever since (1). FET use can reduce the risk of ovarian hyperstimulation syndrome (OHSS) and decrease the incidence of multiple pregnancies (2,3). In recent years, the development of cryopreservation technology has made the frozen-thawed embryo process safer.…”

Impact of elective frozen vs. fresh embryo transfer strategies on cumulative live birth: Do deleterious effects still exist in normal & hyper responders?

“…The connection between oocyte yield and the freeze-all strategy was reported in two population-based retrospective analyses [18,19]. However, these studies had heterogeneous patient populations in terms of the ages of the women and the stages of the embryos selected for transfer.…”

Cumulative Live Birth Rates in Patients with Polycystic Ovary Syndrome: Comparing Progestin Primed Ovarian Stimulation Protocol and GnRH-Antagonist Protocol

“…Cumulative live birth rate per oocyte retrieval summarizes the chance of live birth during an entire treatment period [21,33]. To date, there have been only a limited number of randomized controlled studies (RCTs) compared cumulative live birth rate of 'freeze-all' versus 'fresh-transfer' strategy [34].The result of Li et al demonstrated that the cumulative live birth rate of 'freeze-all' strategy is similar as the 'fresh-transfer' strategy among high responders [35]. None of previous study has compared the cumulative live birth rate of high responders between different treatment protocols.…”