It can look alarming but there's a simple explanation
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Couples can enjoy a better sex life when pregnant even though women have a lot of body changes to contend with when they're pregnant.
There's the swollen ankles, hormonal changes, cravings, stretch marks, weight gain - not to mention the fact you have an actual human growing inside you.
And our minds are tuned in to every change, concerned about making sure baby is safe.
So when you see your stomach harden into a weird shape during sex or after an orgasm, it can be easy to panic about it.
When uterus and abdomen muscles contract during pregnancy, the belly can form a pointed or triangular shape - which can look alarming but it is totally normal and not dangerous - and this contraction tends to happen during or after orgasm.
Expert explains why it's good for pregnant women to have orgasms
You might also notice your belly turning a weird shape when you contract muscles during other activities.
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According to the NHS , late in pregnancy, an orgasm or even sex itself, can set off contractions known as Braxton Hicks.
Women who experience this will feel the muscles of their uterus go hard and it might feel uncomfortable or look odd.
It can cause concern, especially considering that many expectant mothers are hesitant to have sex because of their pregnancy.
But the reality is that this always happens to women - you just feel it more while pregnant.
Women might feel their muscles contract when doing other activities
Bellies should go back to normal quickly and the NHS recommends that you should try relaxation techniques or lie quietly until the contractions pass.
There are benefits to pregnancy sex, though, so it's not all bad news.
Pregnancy changes women's brains for at least two years after childbirth - to make them better mums
As the NCT website explains, pregnant women may feel more sensitive due to the increased levels of hormones in their body and the increased blood flow to their breasts and genitals.
Couples can benefit in the bedroom during pregnancy
They also report that some women even experience their first orgasm, or multiple orgasms, while pregnant - either because of the extra blood flow or due to the fact they're trying different positions and techniques with their partners.