Women whose health insurance covered in-vitro fertilization were more likely to repeat the procedure if necessary, boosting their likelihood of having a baby, compared with women who had to pay out-of-pocket for the pricey reproductive procedure, a new study found.

The study, published this week in JAMA, analyzed the probability that 1,572 women who were IVF patients at a fertility center at Washington University in St. Louis from 2001 through 2010 would have a baby after up to four cycles of treatment. Fifty-six percent of the women had insurance coverage for IVF treatment, 44 percent did not.

Because of the high costs associated with IVF, insurance coverage is a key factor for many people struggling with infertility problems. Fifteen states require that insurers cover infertility treatment, but only a handful require comprehensive coverage of IVF, according to Resolve, an advocacy group for infertility issues. Large companies that pay their workers’ health claims directly are not subject to the state laws, but some still provide benefits.

Researchers found that insurance coverage didn’t affect the likelihood that a patient would have a baby following any single round of IVF treatment. However, if the first cycle was unsuccessful, women with insurance coverage were more likely to return for another round of treatment, increasing their odds. Seventy percent of women with insurance returned for a second round of treatment versus 52 percent of women without insurance.

After four cycles of IVF and taking into account variables such as age, the average cumulative probability that a woman with insurance would have a baby was 57 percent, while a woman without insurance had a 51 percent chance.

“I see this in my practice all the time, that women stop caring because it becomes too much of a financial burden to go on,” said Dr. Emily Jungheim, associate professor of obstetrics and gynecology at Washington University’s School of Medicine, and the study’s lead author.

In-vitro fertilization is a process where sperm and egg are joined outside the body in a lab dish. The fertilized egg is then implanted in a woman’s uterus. The procedure is usually done only after attempts to conceive naturally fail.

The Washington University clinic where the study was based is situated on the border between Missouri, which doesn’t mandate IVF coverage, and Illinois, which requires group health plans to cover up to four IVF egg retrievals.

A typical round of IVF generally costs between $12,000 and $15,000, and the drugs that stimulate the ovaries to produce more eggs may cost another $2,000 to $4,000, said Barbara Collura, president and CEO of Resolve.

Financial issues are “the No. 1 issue in all our surveys,” she said.

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