Nationally, the rate of birth of live twins has continued to increase (Figure 5-7), whereas the rate of birth of live triplets has leveled off since 1998 (Figure 5-8). For births that specifically result from the use of ARTs, the percentage of twin deliveries per ART cycle with fresh nondo-nor eggs or embryos remained essentially unchanged from 1996 to 2003 (31.4 to 31.0 percent). During this period, the percentage of triplets decreased from 7.0 to 3.2 percent (CDC, 2005f). Despite this trend, the number of multiple deliveries in the United States continues to be a problem and is of concern.
MEDICAL AND PREGNANCY CONDITIONS
MEDICAL AND PREGNANCY CONDITIONS
The oversight of ART practices currently occurs at both the governmental (federal and state) and nongovernmental levels, and both governmental and nongovernmental entities also provide the public with guidance on such practices. For a more detailed overview of the goals, scope, requirements, mechanisms, and efficacy of ART-related policies, the reader is referred to Reproduction and Responsibility: The Regulation of New Biotechnologies (The President's Council on Bioethics, 2004). The Fertility Clinic Success Rate and Certification Act of 1992 was designed to provide consumers with reliable information about the services provided by and the success rates of fertility clinics throughout the United States. Data are reported by the Society for Assisted Reproductive Technology (SART) and are published by the CDC. This act also provides states with a standard process for the accreditation of embryo laboratories. In most states, the states oversee access to services and determine whether and to what extent those services are covered by health insurance. Other states address the prevention of abuse by practitioners and regulate gamete and embryo donations.
Nongovernmental guidance on the practice of ART has come primarily from the American Society for Reproductive Medicine (ASRM) in conjunction with SART. In 1999, ASRM issued guidelines that recommended limiting the number of embryos transferred to no more than two in young women in their first cycle of IVF if sufficient embryos were available for cryopre-servation (Barbieri, 2005). A demonstrable drop in the rate of triplet gestations from 7 to 3.8 percent from 1996 to 2002 has been cited as evidence of the success of these practice guidelines (Barbieri, 2005). It is noted that a decrease in the number of triplet live births may be due to factors other than reducing the number of embryos transferred. For example, a distinction should be made between triplet live births and the percent of triplets detected with heart beats since a discordance may exists as a consequence of the use of multifetal reduction. ASRM further refined these guidelines in 2004, recommending the transfer of a single embryo for young women less than 35 years of age with favorable prognoses (Practice Committee of the Society for Assisted Reproductive Technology and the American Society of Reproductive Medicine, 2004). The recommendations become less restrictive as maternal age advances and suggest the transfer of no more than two embryos to women with favorable prognoses between the ages of 35 and 37 years and no more than three embryos in women with favorable prognoses between the ages of 38 and 40 years. Transfer of an additional embryo is suggested if an unfavorable prognosis exists. For women over age 40, the recommended limit to the numbers of embryos transferred is no more than five.
Despite the successes in reducing the rates of higher-order multiple births, the United States does not fare as well as European countries in minimizing the risk of multiple gestations (Anderson et al., 2001). The most recent figures released by the European Society of Human Reproduction and Embryology (ESHRE) reported an overall multiple gestation rate of 25.5 percent among pregnancies conceived by the use of ARTs in 2001, when the U.S. ART-related multiple gestation rate was twice that level. Twenty-four percent of European pregnancies conceived by the use of ARTs resulted in twins, and only 1.5 percent resulted in triplets or higher-order multiple births. By 2001, the United States halved its rate of higher-order multiple births to 3.8 percent, but Europe reduced the rate by nearly 60 percent to a low of 1.5 percent. Furthermore, whereas over half of all U.S. ART cycles involve the transfer of three or more embryos, in Europe over 60 percent involve the transfer of only one embryo (12 percent) or two embryos (51.7 percent). A lower number of embryos transferred may result in lower success rate per cycle. However, continued progress is being made toward addressing the problem of multiple ges tations. A recent study examined the results of approximately 200 IVF cycles in which patients had either one or two embryos transferred. Results revealed similar implantation and live birth rates and a significant reduction in the number of twins conceived with single embryo transfer (Criniti et al., 2005).
The international difference in the rates of multiple gestations may reflect the more stringent guidelines regarding the number of embryos transferred. As early as 1993, the Swedish health organizations recommended reductions in the number of embryos transferred from three to two per cycle. Subsequent voluntary reduction on the part of ART providers virtually eliminated the risk of triplets without lowering the rate of live births (NBHW, 2006). Currently, public funding of ART cycles in Sweden covers only the transfer of single embryos, which has resulted in an even further reduction in multiple gestations. ESHRE guidelines on the recommended number of embryos to be transferred emphasize the elective transfer of a single embryo for women up to 36 years of age if at least one good-quality embryo has been produced. However, there is no scientifically-based definition of what a good quality embryo is, which affects decisions about which and how many embryos to transfer.
Additional support for single-embryo transfer (SET) comes from a recently published randomized controlled trial comparing two cycles of SET with one cycle of double-embryo transfer (DET) (Lukassen et al., 2005). Two cycles of SET were equally effective in achieving a live birth as a single cycle of DET, with similar costs through 6 weeks postpartum. The investigators estimated that if the lifetime costs of caring for handicapped preterm survivors are included, SET will result in a savings of 7,000 pounds per live birth. The investigators noted that in countries where ART regulation is the strictest, the fee structure supports the use of SET (Om-belet et al., 2005; Papanikolau et al.; 2006; Thurin et al., 2004).
The challenge of reducing multiple gestations is also a sensitive and personal issue. The rights and autonomy of patients, the autonomy of providers, and the public good are forces that must be considered (Adashi et al., 2004). Patients may not be rigorously apprised of the risks of multiple gestations or may accept the risks in their desire to conceive. Ovulation enhancement has proceeded without formal guidelines, and advanced training and certification is not required for its practice. With IVF, providers must weigh the goal of a successful singleton pregnancy outcome with the inability to predict the success of implantation of any given embryo. Payers are largely uninvolved in the discussion of the challenge of the risk of multiple gestations. Although some payers underwrite ovulation enhancement, most do not underwrite IVF, the outcome of which is more predictable than that of ovulation enhancement and which results in a lower rate of multiple births. This may be because payers have not been thoroughly informed about the financial consequences of higher-order multiple births.
In an effort to decrease the number of multiple births related to IVF, the Belgian government, in 2003, agreed to reimburse laboratory expenses for the first six IVF trials in women up to age 42. In exchange, restrictions are placed on the number of embryos transferred, depending on the age of the woman (Gordt et al., 2005; Ombelet et al., 2005). For example, in women under 36, single embryo transfer is performed in the first trial and in the second (if high quality embryos are available). Thereafter a maximum of two embryos are transferred. Data reveal that after this policy was instituted, the percentage of singe embryo transfers increased, and overall pregnancy rates did not differ. Twin pregnancies were reduced from 19 percent to 3 percent (Gordt et al., 2005).
Stricter guidelines on the number of embryos transferred should be emphasized by a number of U.S. professional organizations and not just ASRM. Similar best-practice guidelines should be outlined for other infertility treatments that use ARTs, such as ovulation induction. Such guidelines should recommend the use of strict ultrasound guidance and abandonment of a cycle if too many follicles develop. Policy makers should mandate the more systematic collection of data on such procedures and should also consider recommending the use of medication to stimulate egg production. Professional organizations and surveillance activities should redefine success as singleton live births (rather than pregnancy rates). Efforts to reeducate ART consumers on the risks of multiple gestation and preterm birth must transpire simultaneously. Other policies regarding access to assisted reproduction should also be further explored.
Access to reproductive health care and reproductive technology may be a double-edged sword when it comes to ARTs. States with legally mandated coverage for infertility treatment, including ARTs, were the states with the highest rates of ART procedures per million population (Massachusetts, New Jersey, Maryland, the District of Columbia, and Rhode Island) (CDC, 2002b). In Massachusetts, a rise in the state's rate of multiple births can be directly linked to mandated insurance coverage of infertility services (CDC, 1999). Sweden and Belgium exemplify a contrasting approach, with public funding limited to the coverage of only SET cycles, thus freeing infertile couples from the financial pressure to transfer as many embryos as possible.
Was this article helpful?