An Overview of Temporal Trends in Multiple Births After Assisted Reproductive Technology in the USA

Judy E Stern


Expert Rev of Obstet Gynecol. 2013;8(4):357-368. 

In This Article

The Fertility Clinic Success Rate & Certification Act & National Embryo Transfer Guidelines

In 1992 as the result of Federal Trade Commission intervention in a case of false advertising by a fertility clinic, the US Congress held hearings leading to passage of the Fertility Clinic Success Rate and Certification Act.[22] This law requires collection and publication of detailed clinic-specific data on every cycle of ART performed in the USA. Both the CDC and the professional organization SART produce easily accessible online information on outcome for each clinic.[201,202] The data collected are some of the most comprehensive data on any medical specialty in the USA. The transparency created by this data collection has been helpful in exposing clinics with poor live birth rates or unusually high multiple birth rates, although it may intensify competition between clinics, resulting in transfer of more embryos by clinics hoping to display higher rates, than their neighbors.[15] While two recent studies have allayed this fear, both showing no increase in multiple birth rate as a result of competition,[23,24] the concern continues to be voiced. The extent to which clinics might further attempt to disguise their results or 'cherry pick' good prognosis patients to improve their published statistics is not currently known. Unfortunately, if such practices do exist they could put pressure on other clinics to transfer more embryos to obtain delivery rates comparable to those of their competitors.

SART and ASRM have published increasingly strict guidelines on the number of embryos to transfer, each set of guidelines further reducing the transfer number recommended.[25–31] In 1998, the number recommended for transfer to women <35 years of age using their own eggs was three and for women of 40 years, the number was five.[25] As of 2013, the recommendation for good prognosis patients aged <35 years is transfer of one: it is still five for women who are 40 years old having transfer on day 3 postfertilization.[27] Guidelines are not binding and clinicians are free to interpret them for individual patients, however, the mean number transferred at each clinic is published online by SART[201] and CDC[202] along with pregnancy, live birth and multiple birth rates, and this public presentation could hypothetically result in pressure on clinics to bring down their number transferred. An alternate possibility is that some clinics intentionally increase number transferred in order to display higher delivery rates.

Despite the 1992 law and the SART/ASRM guidelines, unusual cases of unacceptably elevated, high order multiple births still occur. The most outlandish example of this was the birth of eight babies to Nadia Suleman, known in the popular press as the 'octomom'. The case engendered a flurry of media attention, calls for regulation and vilification of ART practitioners as addicted to risking the health and wellbeing of women and children. This case, however, tells a greater story that also includes examples of what the professional societies have done to reduce the incidences of such occurrences.

The embryo transfer that led to the octomom birth involved transfer of six embryos (two of which split) to a woman under 35 years of age with prior proven fertility. The transfer number was clearly outside the professional guidelines referred to above. The SART Quality Assurance Committee monitors performance of all SART-associated clinics and up until this case had reviewed the percentage of high order multiples as the major criterion for requiring review of a clinic's procedures. Immediately, after the case was reported, both SART and ASRM took action to discover the causes and specifics of the case.[32] What they found was that the ART clinic that performed the cycle did not have a high multiple birth rate, instead it was one with such an extremely low live birth rate that in 2007 the clinic had performed 19 cycles on women <35 years of age with only a single live birth to show for it (live birth rate of 5% per cycle). The transfer of six embryos to this patient was an example of the balance discussed above to increase live birth rates by increasing the number of embryos. It is also an example of how this increase can occasionally result in an excess of multiples. In this case, rather than appropriately working to improve their technical ability to perform ART, the clinic transferred more. The professional organizations supported the California Licensing Board, which took action against the physician. He was also stripped of his membership in both ASRM and SART. As a result of the case, SART revised its Quality Assurance program to assess the number transferred and live birth rates as well as multiple birth rates. These were strong and definitive actions and while nothing is foolproof, they were major steps toward deterring practice so far out of the professional guidelines in the future.