TEHRAN, Iran – In the middle of the largest political upheaval in 30 years, research in Iran continues.

A new study conducted by researchers from the Urology and Nephrology Research Center at Shahid Beheshti University in Tehran suggests that vaginal birth takes a toll on a couple’s sex life up to one year after the baby is born.

The study, published in the Journal of Sexual Medicine, surveyed 912 pregnant women and their husbands. All the women were healthy and first-time mothers. The aim of the study was to quantify the relationship between mode of delivery and subsequent incidence of sexual dysfunction and impairment of quality of life, both in women and their husbands.

The women were divided into groups based on their type of delivery: spontaneous vaginal delivery without injuries, vaginal delivery with episiotomy or perineal laceration, operative vaginal delivery (includes instrumental delivery such as forceps), planned C-section and emergency C-section.

At the one-year mark, sexual desire had decreased an average of 3.2% in women who had a planned C-section compared to 28.7% among women who had operative vaginal delivery and 14.4% in women who had spontaneous vaginal delivery. Intercourse frequency declined 10.2% among women who had a planned C-section, 32.1% among women who had operative vaginal delivery and 31.4% in women who had spontaneous vaginal delivery.

Exploring the hypothesis that “sexual function” is associated with mode of delivery is important, because sexual health is an integral part of general health.

Another study, conducted in the U.K., came to a similar conclusion, according to askamum.com.

“A study of 482 mums from maternity units in Birmingham found more than half had at least one sex-related problem a year after they’d given birth,” says the site.

Sex was described as painful by 19% of women who had a caesarean, 34% who’d had a normal birth and 36% of who had an instrument-assisted birth. Sex-related health problems were highest among instrument-assisted births (77%) and lowest among Caesarean births (51%).

Amanda Williams, a midwife who worked on the study, said, “Our study points to the need for health professionals to provide ongoing support for women who have given birth.”