Among women undergoing in vitro fertilization, adjusted rates of live birth rose modestly but continuously through up to nine IVF cycles, according to a study published online Dec. 22 in JAMA.
After the researchers accounted for women who stopped trying to conceive by IVF, the estimated cumulative live birth rate was 65% after six cycles, compared with 54% after three cycles and 29% after one cycle, reported Andrew D.A.C. Smith, Ph.D., of the University of Bristol, England, and his associates.
“These findings support the efficacy of extending the number of IVF cycles beyond three or four,” they wrote.
Three unsuccessful embryo transfers, referred to as “repeat implantation failure,” is often seen as a sign to stop IVF, but that opinion is based on a study that did not use intracytoplasmic sperm injection, the researchers noted.
They studied nearly 157,000 women who underwent more than 257,000 IVF ovarian stimulation cycles in the United Kingdom between 2003 and 2010, following them until June 2012. Most women were 35 years old when they began treatment (JAMA 2015;314:2654-62. doi:10.1001/jama.2015.17296).
Women who were younger than 40 years and used their own oocytes had slightly higher adjusted rates of live birth compared with the overall cohort, according to the researchers. The prognosis-adjusted live-birth rate was 32% in the first cycle and 68% at six cycles. In contrast, the live birth rate among women aged 40-42 years was 12% after the first cycle and 31% after six cycles. For women older than 42 years, live birth rates within each cycle were usually less than 4%.
“No age differential was observed among women using donor oocytes,” the researchers wrote. “Rates were lower for women with untreated male partner–related infertility compared with those with any other cause, but treatment with either intracytoplasmic sperm injection or sperm donation removed this difference.”
The researchers were able to assess only live birth as an outcome. But they noted that future studies should consider potential adverse effects of additional cycles of treatment, including ovarian hyperstimulation syndrome and a potential increased risk of preterm birth or congenital anomalies.
“For some couples, the emotional stress of repeat treatments may be undesirable, and the cost of a prolonged treatment course, with several repeat oocyte stimulation cycles, may be unsustainable for health services, insurers, or couples,” the researchers wrote. “However, we think the potential for success with further cycles should be discussed with couples.”
The UK Medical Research Council, the National Institute for Health Research, and the Wellcome Trust funded the study. One coauthor reported financial relationships with Beckman Coulter, Besins, Ferring, Merck Serono, Merck Sharp & Dohme, and Roche Diagnostic. The other researchers reported having no financial disclosures.