May 4 (UPI) -- Women who eat fast food-four or more times a week were less likely to conceive within a year and more frequently experience infertility than those who consume a healthy diet, according to a new study.
Researchers analyzed the diets of 5,598 women in Australia, New Zealand, Britain and Ireland from November 2004 to February 2011. Their findings were published Friday in the journal Human Reproduction.
"The findings show that eating a good quality diet that includes fruit and minimizing fast-food consumption improves fertility and reduces the time it takes to get pregnant," Dr. Claire Roberts, a research fellow at the University of Adelaide in Australia, said in a press release.
Fast-food, which included burgers, pizza, fried chicken and chips, were bought at fast-food and other takeout restaurants, and not purchased from supermarkets.
In total, 8 percent of the couples took 12 months to conceive, while 39 percent conceived in one month or less. The researchers excluded couples who received fertility treatment because of male infertility, and 94 percent of the women received no fertility treatments before conception.
The study found women who ate fruit three or more times a day increased chances of becoming pregnant quickly. But those who ate fruit less than one to three times a month took half a month longer to conceive.
Women increased their risk of infertility -- not being able to get pregnant after one year -- from 8 percent to 12 percent if they ate the least amount of fruit. The risk increased from 8 percent to 16 percent if they ate fast food four or more times a week.
"We recommend that women who want to become pregnant should align their dietary intakes towards national dietary recommendations for pregnancy," said Jessica Grieger, a post-doctoral research fellow at Adelaide. "Our data shows that frequent consumption of fast-foods delays time to pregnancy."
The data were collected from midwives around the fourth month of pregnancy. The researchers asked women their diet in the month before conception and how frequently they consumed fruit, green leafy vegetables, fish and fast-foods.
"For any dietary intake assessment, one needs to use some caution regarding whether participant recall is an accurate reflection of dietary intake," Grieger said. "However, given that many women do not change their diet from pre-pregnancy to during pregnancy, we believe that the women's recall of their diet one month prior to pregnancy is likely to be reasonably accurate."
The researchers are expanding their research to identify particular dietary patterns, rather than individual food groups, to help understand why it takes them longer to become pregnant.