Women who have an unwanted pregnancy are at higher risk of developing mental health problems, a new review of nearly 50 studies has revealed.

According to the study, led by Dr Tim Kendall of the UK's National Collaborating Centre for Mental Health, about 12 per cent of women in general suffer from mental health problems, such as anxiety or depression. However, with women who have unwanted pregnancies, this figure is three times higher.

The review, which looked at 44 worldwide studies from 1990 to 2011, also found that abortion does not increase the risk of developing mental health problems.  The review focused on women who had unwanted pregnancies, yet found the best indicator of mental health problems was to look at whether the women had psychiatric issues before getting pregnant.

Dr Kendall told the Associated Press that people should "be looking at what it is about the unwanted pregnancy stage that is so problematic". He went on to say that "We need to try to get those women help sooner so they're not put at greater risk."