Unexpected pregnancy? Anatomy expert reveals sex acts that aren’t as conception-proof as people might think…

Safe sex is essential for young couples who don’t want children, but some methods may not be as pregnancy-proof as you might think.

Women have conceived children in surprising ways that seem to defy the laws of biology.

What they all have in common is the resilience of the human reproductive system and its ability to perform against the odds.

Professor Adam Taylor from Lancaster University has detailed how women can become pregnant in four extremely rare circumstances: through anal sex, oral sex, a ‘splash’ insemination without any penetration and while they are already pregnant.

Getting pregnant through anal sex is extremely rare, but it can happen in people with a reproductive abnormality called a cloacal malformation.

Anal sex may seem like a safe option for couples who want to avoid pregnancy, but a rare condition can prevent sperm from reaching the egg

The only truly safe way to prevent pregnancy is to use contraception, experts say

This occurs when the separation tissue between the vagina and the anus is not properly formed.

When this happens, the sperm can swim through the openings in the dividing wall to the egg to fertilize it.

Professor Taylor said sperm cells are naturally attracted to the egg by sensing traces of the chemicals the egg produces, and will take any route they can to reach their destination.

“They are able to detect traces of chemicals that the egg produces,” he said The conversation.

‘As the sperm swim toward the egg, the amounts of these “chemoattractants” they detect increase, signaling them to keep traveling in the right direction.’

Cloacal malformations occur in one in 50,000 girls and require corrective surgery.

There is a high risk of complications with this surgery, such as incontinence and problems getting pregnant.

Medical records detail a pregnancy that resulted from a bizarre set of circumstances and began with oral sex in 1988.

A 15-year-old girl from the southern African country of Lesotho went to her doctor with abdominal pain and turned out to be heavily pregnant.

Oral sex should be a safe bet to prevent pregnancy, but the determination of sperm to reach their target should not be underestimated

A girl born without a vagina became pregnant in 1988 after a traumatic experience that began with oral sex (stock photo)

But incredibly, the girl was born without a vagina, a condition called Mullerian agenesis. Everyone wondered how this could happen.

Nine months earlier, it emerged that she was giving a blow job to her lover and that she had been caught by her jealous ex-boyfriend, who promptly stabbed her in the stomach.

She went to the hospital and was treated, but not before her lover’s sperm entered her body.

Sperm cells are known to survive in the peritoneal cavity, the space between the abdominal organs and the body wall.

In the girl’s case, her lover’s brave swimmers managed to reach her egg and fertilize it, possibly via her gastrointestinal tract.

Doctors delivered a healthy baby via caesarean section, according to a report in the British Journal of Obstetrics and Gynaecology.

There are also other ways women can become pregnant even if they have not had intercourse.

‘If sperm splashes against the external genitals, the sperm can enter the vagina and swim towards the ovaries,’ explains Professor Taylor.

Women can become pregnant during sexual activity even if they have not had full intercourse

Healthy sperm have great resilience and can survive outside the human body for half an hour

The chance of so-called ‘splash pregnancies’ is small, because sperm cannot survive outside the body for more than half an hour.

Healthy sperm swim at a speed of up to 5 mm per minute and can survive in the female reproductive tract for up to five days.

Under ideal conditions, hundreds of millions of sperm enter the vagina during sex, but only 200 to 300 of them reach the egg. This shows how rare varicose pregnancies are.

They cannot be caused by sperm in bath water or hot tubs, because the water disperses the sperm and dilutes the seminal fluid that protects it.

Chemicals such as chlorine in the water also quickly kill sperm.

In very rare cases, a woman can become pregnant for the second time while already carrying a baby.

This phenomenon is called superfetation and throws out all the ‘safeguards’ that normally prevent a second pregnancy.

Hormonal changes during pregnancy usually prevent a second pregnancy from occurring

In very rare cases, called superfetation, a second egg can be fertilized while a woman is already carrying a baby

During pregnancy, a woman’s hormones change to prevent an embryo from implanting in the uterine lining.

Even if a second embryo were to somehow be created, it is unlikely that it would be able to grow in the uterus.

This is even true for women who are born with two uteruses, as these mechanisms work hard to prevent a second pregnancy.

Hormones prevent ovulation and cause a thick mucus plug to form over the cervix, which prevents sperm from traveling through the uterus to the ovaries.

But very occasionally, usually in women undergoing IVF treatment, these safety precautions can be ignored.

The two pregnancies often occur shortly after each other, usually within two to four weeks.

Although the babies are not twins, they can usually be born at the same time.

Most of these pregnancies are normal and without complications.

Professor Taylor said: ‘These examples are of course extremely rare – so you probably don’t need to worry too much. But if you’re not planning on getting pregnant any time soon, make sure you use contraception.’