Couples who turn to fertility clinics for help getting pregnant might expect to pay more than $24,000 out-of-pocket for in vitro fertilization (IVF), California researchers find.

Yet success rates hover around only 50 percent, according to data from eight clinics in northern California.

"I can't say I was surprised, but I was taken aback by the numbers," study researcher Patricia Katz, of the University of California, San Francisco, told Reuters Health. "They're high."

Writing in the journal Fertility and Sterility, Katz and colleagues say they launched the study to provide "realistic estimates" for couples to consider before they take what can be a very expensive plunge.

Between one and two percent of American women undergo fertility treatment, mainly IVF, at some point in their lives.

Insurance companies often don't cover the treatment, which may end up taking a significant bite out of the family's nest egg and quality of life, Katz said.

The researchers followed 398 patients from the first evaluation visit through 18 months of treatment. Of the 311 patients who decided to get treatment, there were 105 deliveries and 40 ongoing pregnancies when the study ended.

The study is the first to include the full range of infertility treatments -- from medication-only, to insemination, to IVF with a donated egg -- and estimate the costs for each woman. The team also included the hospital costs of maternal and neonatal care.

Fertility medications work by stimulating a woman's production of eggs, whereas IVF involves fertilizing a woman's egg or a donated egg outside the body and returning it to the womb to develop.

The team found that the cost went up with the intensity of treatment, from a low of $1,182 for medication-only, to $24,373 for IVF using the woman's own eggs and $38,015 for IVF using donated eggs.

When the numbers are crunched to reflect only those women who were successful -- 47 percent -- the costs climbed many thousand dollars, reaching more than $76,000 for IVF.

The researchers say their cost estimates may even be too low, because they don't include couples still under treatment after the study ended.

Katz said that by putting the costs entirely on the backs of individuals, the health care system may encourage riskier treatment decisions that cost insurance companies more in the long run.

For instance, couples may be more likely to have multiple eggs implanted at one time, which increases the risk of having multiple babies. Katz' team found the delivery costs for such births was about $22,866, or nearly three times higher that of singleton births. Multiple-birth babies are also at higher risk for costly health problems such as premature birth.

By contrast, fertility treatments are covered in Europe, where single-egg implants are the norm, Katz said.

Apart from providing couples with an idea of how much they'll have to shell out for fertility treatment, Katz said her findings argue that the treatment should be covered.