A leading midwife has warned of the risks to unborn children from measles after 781 cases were reported in England since January - up from 274 in the whole of 2017.
Janet Cairns, Head of Midwifery at Hull and East Yorkshire Hospitals NHS Trust, said catching measles during pregnancy can cause miscarriage, stillbirth or premature labour.
She said: "Now is the right time to check if you and your family are vaccinated against the risk of measles.
"GPs can advise, and give vaccines to anyone who has not been adequately protected. Two doses of the MMR vaccine can prevent more than 95 per cent of cases of measles, mumps and rubella.
"If you are pregnant and have been in contact with someone with measles, which is infectious from a few days before the rash appears, please contact your GP or midwife, who can request a blood test to check whether you are immune."
Figures from Public Health England (PHE) show that most measles cases have been reported in London, followed by the South East, South West, West Midlands and Yorkshire and Humber, where there have been more than 70 since the start of the year.
According to NHS guidance, pregnant women who think they have come into contact with someone with measles and know they are not immune should see their GP urgently.
New cases in Britain have been linked to a European outbreak, prompting health officials to call on travellers to make sure they have had their MMR jabs.ey
Uptake of the MMR vaccine fell heavily in the late 1990s following the publication of research by Andrew Wakefield which suggested a possible link between the inoculation and autism.
Experts have widely discredited his study and he was struck off the medical register in 2010.
While vaccine uptake levels in the UK in young children are currently very high, coverage levels dipped to a low of 80 per cent in 2003.
Warnings have been made that as a result, many teenager and young adults are unprotected against the viral illness, which can be deadly in some cases.