(Reuters Health) - Women who eat a lot of fast food may take longer to become pregnant and be more likely to experience infertility than their counterparts who rarely if ever eat these types of meals, a recent study suggests.

Compared to women who generally avoided fast food, women who indulged four or more times a week before they conceived took almost a month longer to become pregnant, the study of 5,598 first-time mothers in Australia, New Zealand and the UK found.

Overall, 2,204 women, or 39 percent, conceived within one month of when they began having sex with their partner without contraception and 468, or 8 percent, experienced infertility and failed to conceive after 12 months of trying.

While women who rarely or never ate fast food had an 8 percent risk of infertility, the risk was 16 percent among women who ate fast food at least four times weekly.

“Fast foods contain high amounts of saturated fat, sodium, and sometimes sugar,” said lead study author Jessica Grieger of the Robinson Research Institute and the University of Adelaide in Australia.

“Although these dietary components and their relationship to fertility has not been specifically studied in human pregnancies, higher amounts of saturated fatty acids were identified in oocytes (an egg cell in the ovary) of women undergoing assisted reproduction and studies in mice have demonstrated that a high fat diet had a toxic effect on the ovaries,” Grieger said by email. “We believe that fast food may be one factor mediating infertility through altered ovarian function.”

Roughly 1 in 10 women of childbearing age have difficulty getting pregnant. Most of the time, it’s caused by problems with ovulation, often related to a hormone imbalance known as polycystic ovarian syndrome (PCOS). Some signs that a woman is not ovulating normally include irregular or absent menstrual periods.

Less-common causes of infertility in women can include blocked fallopian tubes, structural problems with the uterus or uterine fibroids.

The risk increases with age, and can also be exacerbated by smoking, excessive drinking, stress, an unhealthy diet, too much exercise, being overweight or obese or having sexually transmitted infections.

Women in the current study were typically overweight and most of them ate fast food at least twice a week, the study team notes in Human Reproduction.

Researchers also looked at how often women ate fruit and found that those who had it less than once a month took half a month longer to become pregnant than women who ate at least three fruit servings a day.

With the lowest fruit intake, the risk of infertility was 12 percent, compared to 8 percent with the highest fruit consumption.

The study wasn’t a controlled experiment designed to prove whether or how the amount of fruit or fast food women consume might impact their fertility. Another limitation is that researchers relied on dietary questionnaires women completed during prenatal visits that asked them to recall how they ate in the month before they conceived - a method that isn’t always accurate.

“A lot of maternal lifestyle factors are associated with infertility, like smoking, alcohol drinking or obesity,” said Dr. Joachim Dudenhausen, a clinical professor of obstetrics and gynecology at Weill Cornell Medicine in New York City.

The current study offers fresh evidence of the role diet can play in helping women conceive, Dudenhausen, who wasn’t involved in the study, said by email.

“There are some studies showing that preconception intake of fruits and fish increase fertility,” Dudenhausen said. “The study is in the same line and has clear data supporting the advice for women who wish to get pregnant to have greater intake of fruit and lower intake of fast food.”

SOURCE: bit.ly/2Ic3Y6R Human Reproduction, online May 4, 2018.