Women who are afraid to give birth tend to have longer labor than women who are more relaxed about the process, new research suggests.

Researchers in Norway found women fearful of giving birth spent about an hour and a half longer in labor than other women (about eight hours compared to six and a half hours).

Fear of giving birth was also associated with a greater likelihood of an instrumental vaginal delivery or an emergency Cesarean section.

The study was published June 27 in BJOG: An International Journal of Obstetrics and Gynaecology.

Researchers surveyed more than 2,200 women pregnant women, about half of whom were going to be first-time mothers, about their attitudes toward childbirth. About 7.5 percent of the women were afraid of childbirth.

Even after taking other factors into account that could prolong labor, such as epidural anesthesia and labor induction, labor for the women who feared childbirth was longer than for more relaxed women.

But, the study authors pointed out that even though women who feared childbirth labored longer, 89 percent managed to deliver vaginally, compared to 93 percent of women who did not fear giving birth.

"Fear of childbirth seems to be an increasingly important issue in obstetric care," study co-author Samantha Salvesen Adams, of Akershus University Hospital, said in a journal news release.

"We found a link between fear of childbirth and longer duration of labor," Adams said. "Generally, longer labor duration increases the risk of instrumental vaginal delivery and emergency caesarean section. However, it is important to note that a large proportion of women with a fear of childbirth successfully had a vaginal delivery and therefore elective Cesarean delivery should not be routinely recommended."

Experts note that while this study found an association between fear of childbirth and longer labor, it didn't prove that anxiety about giving birth caused the longer labors. Agencies