A woman has become pregnant from anal sex in case which is believed to be one of the first recorded of its kind. While it would appear to be a medical impossibility, a US doctor has spoken of his surprise at discovering it had occurred to one of his patients.

Dr Brian Steixner MD, Director of the Institute of Men’s Health at Jersey Urology Group in Atlantic City, has explained that one of his patients had a condition termed cloaca. It occurs in the womb when a female foetus’ bladder, vagina and rectum do not develop normally and instead intestinal, urinal and reproductive functions are all performed from the same orifice.

The woman was referred for surgery to correct this when she was younger as is standard treatment for cloaca cases. However the surgery was botched, resulting in her uterus being wrongly connected to her rectum.

Years later, she became pregnant, to the surprise of Dr Steixner and his colleagues. He told Men’s Health: “We knew about her condition, and we had followed her for a decade. After doing a whole bunch of X-rays, we determined that she got pregnant from having anal sex.”

The condition raised the urgent question of whether a safe birth would be possible for both mother and child as she did not have a viable vaginal passage. Dr Steiner said: “The obgyns couldn’t figure out a way to effectively deliver the baby through the rectum safely. So she had a C-section.”

When teenage pregnancy is a death sentence Show all 2 1 /2 When teenage pregnancy is a death sentence When teenage pregnancy is a death sentence SU-08-teenpregnancy1-.jpg Tadej Znidarcic When teenage pregnancy is a death sentence SU-08-teenpregnancy3-.jpg Tadej Znidarcic

However, Dr Steixner says that the case should not be cause for concern for anyone worried about conceiving in this way. He told The Independent: “This case is one in a billion and the rarest of the rare. I’m not sure it should be a big issue for women generally.”

The Cloacal Malformation Multidisciplinary unit at Great Ormond Street Hospital for Children advises: “Cloacal malformation is a congenital (present at birth) problem that only affects girls. Very early in pregnancy, the rectum, uretha and vagina fail to separate into separate tubes.