Lessons learned in reducing multiple pregnancy rates in infertility treatment
Views and reviews section. Fertil Steril. 2020;114:671- 672; 673-679; 680-689; 690-714; 715-721.
In the October 2020 issue of Fertility and Sterility, the Views and Reviews section included 5 articles on avoiding multiple live birth rates (LBRs) in assisted reproductive technologies (ART).1-5 International experts provided a comprehensive review of global multiple LBRs and their associated negative impact on maternal and perinatal outcomes, reasons for global variability, strategies to reduce multiples, single embryo transfer, and implications of funding and reporting. These international comparisons and recommendations are helpful and applicable to infertility care in the United States.3
The rise of multiple birth rates
During the first decade of in vitro fertilization (IVF), live birth rates were low, increasing to 14% in 1990. Multiple embryos needed to be transferred so that even these LBRs could be obtained. In the 1990s, however, laboratory technology improved rapidly, with increased implantation rates and subsequent rapid increases in LBR, but also with increased multiple birth rates (MBRs).
In the United States, clinic-specific reporting helped create competition among clinics for the best LBRs, and this led to MBRs of 30% and higher. Numerous studies documented the associated significantly increased morbidity and mortality of both mothers and babies. Similar situations occurred in many other countries while some, especially Nordic nations, Australia, New Zealand, and Japan, had twin rates of less than 10% or even 5% since the early 2000s. So why the difference?
The higher MBR is due largely to the transfer of more than one embryo. The immediate solution is therefore always to perform elective single embryo transfer (eSET). However, numerous factors affect the decision to perform eSET or not, and this ideal is far from being achieved. Older women, those with longer duration of infertility and/or failed treatment, often feel a time pressure and want to transfer more embryos. Of course, biologically this is reasonable because the number and quality of their embryos is lower. While attempts have been made to assess embryo quality with preimplantation genetic testing for aneuploidy, evidence that this increases the LBR is controversial except possibly in women aged 35 to 38 years. This is especially true when the cumulative LBR, that is, the number of live births after transfer of all embryos from an egg retrieval cycle, is the measured outcome.
The major factor that determines the frequency of eSET is financial. Affordability is the out-of-pocket cost (after insurance or other subsidy) as a percentage of disposable income, and it is the most important factor that determines whether eSET is performed. Less affordable treatment creates a financial incentive to transfer more than one embryo to maximize the pregnancy rates in fewer cycles.5 Other factors include whether the effectiveness of treatment, that is, LBR, is emphasized over safety, that is, MBR. In the United States, the Society for Assisted Reproductive Technology now reports cumulative LBR, singleton and multiple LBR, and preterm births as outcomes, thereby increasing the emphasis on eSET.
Sociologic, cultural, and religious factors also can affect the frequency of eSET. Even within the United States, great variation exists in values and beliefs regarding infertility treatment. It can be challenging to determine who makes decisions: the patient alone, the physician, the payor, professional guidelines, or laws. In many countries, including the United States, it is an amalgam of these.
Setting new goals
If the goal is to reduce the MBR, what should that rate be? In the past few years, the MBR in the United States has been reduced to approximately 10%. It is reasonable now to set a goal of 5% in the next several years. To do this, we can learn from countries that have been successful. The United States already has very high-quality clinical and laboratory services, knowledgeable physicians, and a reasonable regulatory environment. Improved technology, specifically embryo selection for transfer, and focus on adherence to established embryo transfer guidelines could help.
Many would argue that eSET essentially should be performed always in women younger than age 40 and in all women of any age with a known euploid embryo. The major problem that drives multiples is the lack of affordability, which can be addressed by increased subsidies from payors. Increased subsidies can result from legislative mandates or societal pressures on employers, either of which could be associated with requirements for eSET and/or reduced MBRs.
In your practice, you can now reassure your infertility patients that cumulative LBRs are excellent in the United States and that the risk of multiple pregnancy has been reduced dramatically. This should encourage more patients to accept and take advantage of this successful technology that has resulted in the birth of millions of babies globally. Further reduction of the MBR to 5% should be possible within a few years through education and advocacy by women’s health care clinicians that results in increased subsidies and more affordable IVF.
WHAT THIS EVIDENCE MEANS FOR PRACTICE
The multiple birth rate in ART has been reduced to 10% in the United States through an increased understanding of the complex factors that affect embryo transfer practices globally. Further progress will depend primarily on increased subsidies that make ART more affordable.
The multiple birth rate in ART has been reduced to 10% in the United States through an increased understanding of the complex factors that affect embryo transfer practices globally. Further progress will depend primarily on increased subsidies that make ART more affordable.
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