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Lucy Mecklenburgh has been on the receiving end of harsh criticism after she promoted the use of a 'natural contraceptive' app on Instagram.
The 29-year-old, who shares son Roman with fiancé Ryan Thomas, previously said she felt "uncertain" sharing what sort of contraception she uses with her 1.7 million followers.
She then went on to explain she uses Natural Cycles, an app that judges whether you are fertile or not by asking users to input their temperature.
"I have struggled with contraception for years trying every pill there is as well as the coil none of them worked for me. I experienced really bad side effects but didn't really know of any non-hormonal options," she said in her post.
"All I do is measure my temp each morning and the algorithm calculates my fertility status for the day. If it's a Green Day, I'm not fertile and I don't have to use protection and if it's a Red Day, I'm fertile and I have to use protection - simple as that!"
However, fans were quick to criticise former TOWIE star Lucy for promoting Natural Cycles, with many saying that it was inappropriate to advertise to her young fan base.
"I cannot believe this is being promoted, how incredibly irresponsible!" one person wrote. "Yes it might work for some, but for many it's just not ok!
"Sure if you're in a stable relationship, financially ok and would be happy if you did get accidentally pregnant, it's probably great. To anyone else, just no."
"I've read a lot into this and it's very dodgy- nowhere near as effective as hormonal contraception," a second added. "Be very careful, unless you want to get pregnant. I'm really surprised you're endorsing this Lucy."
A third wrote: "Thanks to Natural Cycles, I have a beautiful and very unexpected son."
However, Lucy has found someone who has since defended her use of the contraceptive - doctor Emily Andrea, who stressed that someone's choice of contraception is their business.
Emily, who is married to Peter André, wrote in her OK! column: "Contraceptive methods are something that are completely personal. Something that will work for one person, won't work for another - with some forms of contraception more effective than others.
"No form of contraception is 100 per cent effective, so as long as you know the risks and benefits of the method you choose then it's totally up to you. Your GP can talk you through all the options and work out what's best for you."
Natural Cycles claims to be 93 per cent effective with typical use, compared to 99.9 per cent effectiveness hormonal contraception can offer when used properly.
It should also be noted that neither method protects you from sexually transmitted diseases.
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