The average mum-to-be can expect to get just five hours sleep a night during her pregnancy. A detailed study found overall nine in ten suffered from a lack of sleep with 20 percent admitting they had endured ‘extremely disrupted’ nights. More than half of soon-to-be mums confessed they were reduced to tears by severe tiredness while carrying their unborn child. The most common issues for disprupted sleep were the constant need to get up for the loo, heartburn and simply being 'too hot'.