How a woman got pregnant from having anal sex.

Heard the story about the woman who got pregnant from anal sex? No, it’s not the start of a bad joke but a real life situation that’s been making the rounds again recently.

This time last year, US-based urologist Dr Brian Steixner told Men’s Health that he treated a pregnant woman who arrived at the hospital one night complaining of spotting. This is not entirely unusual in a pregnancy, except when the blood is coming from your rectum.

Understandably, people were horrified – had they really been lied to by sex ed teachers, past sexual partners and sealed sections everywhere?

No, not exactly. Short answer? The risk is pretty damn minimal. The long story, however, is pretty fascinating.

In this particular case, the woman (we’ll call her Leslie) had a condition called a ‘cloacal malformation’. This means when she was born, her bladder, vagina and rectum were not fully developed, leaving her intestinal, reproductive and urinary tracts to come out of one single hole.

Watch: People confess their most embarrassing sex moments. Post continues after video

According to the UK’s Great Ormond Street Hospital, it occurs in one in 50,000 live births of females.

Cloacal anomalies can also include multiple vaginas, a malformed anus and other defects of the ureters and kidneys.

The exact cause is unknown and the treatment is described as one of the “most formidable technical challenges in pediatric surgery”.

The American Urological Association details that the first task is surgery to stabilise the patient (usually a newborn) with a colostomy to allow it to ‘pass stools’.

Once that has occurred and the anatomy has been clearly defined, reconstruction can happen – the rectum is detached from the vagina, the common channel is brought to the surface of the skin, divided into two and openings for the vagina and urethra are put in the right spots.

Image: iStock

Doctors aim to achieve an anatomic reconstruction and achieving bowel and urinary control, as well as normal sexual function for their patient.

Failure to identify a persistant cloaca condition or treatment too late can cause some serious complications.

"The patient may then receive only a colostomy and may subsequently experience sepsis, acidosis, and, sometimes, death," says lead researcher Marc A Levitt, MD.

According to Dr Steixner, when Leslie had this surgery when she was younger to correct the problem, the surgeons misconnected her uterus to her rectum, meaning she had a "blind-ending vagina" - a vagina that looks a bit like a pouch rather than leading anywhere else.

"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," Steixner said. (Post continues after gallery.)

Famous sex scenes.

He reports she had the baby delivered by C-section.

Reassuringly, this outcome, even among people with this condition, is extremely rare. Leslie's is the only case (based on Dr Steixner's account) publicly detailed where this has happened.

However if you're still worried about it, make an appointment to see your doctor or a specialist.

If your genitals are "normal", it's highly, highly unlikely you'll get pregnant through anal sex (although in theory it's technically possible if semen from the anus leaked into the vagina and traveled to fertilise an egg. Again, this is very unlikely.)

According to Julia Brown Lancaste of Crozer-Keystone Women's Health, what you should actually be worrying about are STDs rather than pregnancy.

"The risk of getting an STD is higher with anal sex than vaginal sex because the lining of the rectum is extremely thin and can tear easily, allowing infection to get into your body," she told Kids Health.

So use one of these, people.

Protection is key. Image: iStock.

... And you may now continue your fun with peace of mind.

Image: iStock.

Have you heard of a worrying sex myth like this?