The Grapevine

Undergoing More Than 4 IVF Cycles May Increase Women's Chances Of Live Birth

IVF
IVF is commonly stopped after three or four unsuccessful cycles, but UK researchers find many women who persist see success up to and including the sixth cycle. sabianmaggy, CC BY 2.0

In vitro fertilization is a great option for couples struggling with infertility, but it commonly takes multiple cycles before an embryo transfers successfully. If transfers are still unsuccessful after the third or fourth cycle, IVF is stopped — but does continuing past this point equal success? Yes, according to a new study published in JAMA that found an average of six cycles increased the likelihood of a live birth.

The study authors cite "with [one] exception, previous studies of cumulative pregnancy or live-birth rates have been relatively small, with limited ability to precisely estimate cumulative success beyond four transfers." But these studies also defined a cycle of IVF as an embryo transfer, meaning cycles with repeated embryo transfers were counted separately. When you consider how much IVF has improved over the past 10 to 15 years, from a single to a frozen embryo transfer, the authors believe IVF success should instead be calculated by the "live-birth rate per initiated ovarian stimulation, including all subsequent separate fresh and frozen embryo transfers."

Authors analyzed data collected by the UK Human Fertilization and Embryology Authority between 2003 and 2010, including data on women’s individual cycles and birth outcomes. Live birth was defined as "an infant born alive after 24 weeks gestation who survived longer than one month." And a cycle of IVF was defined as "the initiation of ovarian stimulation and all resulting separate fresh or frozen embryo transfer."

In the end, study authors were able to see data for 156,947 women who received 257,398 IVF cycles over the course of the study — among them, the live-birth rate for the first cycle was 29.5 percent. This rate remained above 20 percent into the women’s fourth cycle. But the adjusted live-birth rate across all cycles continued to increased up to the ninth cycle, with 65.3 percent of women achieving a live birth by the sixth cycle, the authors wrote.

Live birth rates varied by age: Women younger than age 40 saw a live birth rate of 32.3 percent for the first cycle, which remained above 20 percent up to and including the fourth cycle with six cycles achieving a cumulative live birth rate of 68.4 percent. The first-time rate for women aged 40 to 42 was 12.3 percent, with six cycles achieving a cumulate live birth rate of 31.5 percent, while women over the age of 42 experienced 4 percent rates within each cycle.

Generally, rates were lower for women with untreated male partner-related infertility compared to those with any other cause — treatment with either intracytoplasmic sperm injection or sperm donation removed this difference, the authors said.

"To our knowledge, this is the first study to have linked fresh and frozen embryo transfers to obtain estimates of live-birth rate within each IVF ovarian stimulation cycle and cumulative live-birth rates across repeated stimulation cycles," they added. "Despite a decline in the success rate within each cycle as the number of these increased, the cumulative rate across cycles increased up to the ninth in the whole cohort, women younger than 40 years (using their own oocytes), and women using donor oocytes (irrespective of age)."

However, study authors noted that in these women, five cycles took an average of two years. They also acknowledged their study was not without limitations. Though authors were able to assess live birth as an outcome, they suggested further research consider potential "adverse effects of continued treatment, including ovarian hyperstimulation syndrome and possible increased risk of preterm birth, low birth weight, or congential 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 study authors concluded. "However, we think the potential for success with further cycles should be discussed with couples."

Source: Smith A, Tilling K, Nelson SM, Lawlor DA. Live-Birth Rate Associated With Repeat In Vitro Fertilization Treatment Cycles. JAMA. 2015.

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