A new study suggests that sun exposure is protective against getting pregnant.

The study, published in the journal Environmental Health Perspectives, looked at a group of 3,000 pregnant women who reported sun exposure to a doctor at the time of their first pregnancy.

Those women who had been exposed to the sun at least once a week during their pregnancies were less likely to be pregnant after giving birth.

The results suggest that sun protection is beneficial for women who get pregnant, said lead author Dr. Lisa D. Zangaro, a clinical assistant professor of obstetrics and gynecology at Baylor College of Medicine in Houston.

“This study was designed to address the question, how does sun exposure protect women from getting pregnant?,” Zangaros said.

Women who received the highest amount of exposure to the light during their first trimester of pregnancy were more than twice as likely to give birth to a child born with a head circumference of at least 4 inches (12 centimeters) when compared with women who did not receive sun exposure during their pregnancy.

The researchers also found that the sun may be able to protect against pregnancy.

Women whose sun exposure was between one and three times higher than that of those who did less sun exposure at the start of pregnancy, for example, were more likely to get pregnant later in pregnancy, they said.

“Women who have been exposed for a longer time and who are more vulnerable to the effects of the sun during pregnancy are particularly at risk of pregnancy complications,” Zampese said.

About 1.5 million Americans are at risk for pregnancy complications, according to the Centers for Disease Control and Prevention.

The sun may also be responsible for the birth defects that have been found in fetuses of women with a higher risk of having a birth defect such as Down syndrome.

Other studies have found that exposure to ultraviolet radiation during pregnancy may increase the risk of developing birth defects in children.

But the new study is the first to look at sun exposure in terms of pregnancy prevention, said study author Drs.

Rebecca A. Wolski and Daniel R. Shiffman, both from the University of Alabama at Birmingham, who were not involved in the study.

“We’re not saying that sun prevents pregnancy, but we’re looking at a mechanism of action,” Wolskin said.

The women in the new paper had an average age of 37.

They were white and middle-aged.

About half of the women were white, half were Hispanic.

About two-thirds of the pregnant women had an education of at or below high school.

More than half of them had at least one previous pregnancy.

Researchers said they did not know how much sun exposure the women received.

Some of the studies did not account for sun exposure from outside the home.

Zampos said the study has limitations, including the fact that the women who received more sun exposure were less fertile than those who received less.

Wollyski said there are a lot of ways that sun may increase pregnancy risks, but that there was little evidence that sun has an effect on the likelihood of conception.

For example, the women in this study were exposed to a wide range of wavelengths from ultraviolet to visible light, which can cause skin cancer, the researchers said.

Sun exposure also affects the immune system.

Wenski said it is possible that sun can decrease the risk for other types of infections such as HPV, or even HPV-related cancers.

“What’s really important is to look for ways to protect women in other ways that are not directly related to sun exposure,” Wollieski said.