Most mothers have less sex after giving birth because their libidos crash, a survey said yesterday.

By the time their children are toddlers, 62% of women cannot match their partner’s sex drive, according to research from parenting website Netmums.com.

Many of the 7,000 mothers questioned had more sex during pregnancy than afterwards, and one in five said their sex lives actually improved while they had a bump, with hormones boosting their desire to make love.

But after giving birth they shun the bedroom, opting to be good mums rather than hot lovers, with one in five having sex less than once a month.

Nearly all mothers believe that good sex is vital in a relationship, but 42% said they can take it or leave it. And one in ten admitted to doing anything it takes to avoid sex.

A sex guide for mums — the Mama Sutra — was launched online yesterday, based on the survey’s results.

Siobhan Freegard, founder of Netmums, said: “Mothers recognise how important it is for maintaining a healthy relationship but the reality is that many women find making the transition from mother to lover difficult.

“We really hope that Mama Sutra will help women across the country to improve their physical relationship with their partner this Valentine’s Day.”

Tips include wearing sexy undies while doing the housework and having sex while the children sleep. Visit Netmums.com/mamasutra.