Expectant mothers will be urged to avoid unnecessary journeys and crowds, with experts suggesting that they do not travel on trains and the London Underground at peak times.

Parents will be advised to keep babies away from crowds, while pregnant women will also be encouraged to limit the movements of their other children, so they do not bring the virus home.
 
The warnings come amid increasing concern that pregnant women and young children are among the groups most at risk from swine flu.

So far, more than 650 people have been taken to hospital with the virus in England, including more than 200 children.

Under-fives have been three times more likely than older patients to be taken to hospital. In Scotland, 44 people have been taken to hospital, while 11 have been treated in Welsh hospitals. At least 146 cases have been recorded in Ireland.

Officially, there have been 29 British deaths involving swine flu, including four children and two mothers who died shortly after giving birth.

All except one – six-year-old Chloe Buckley, who died 10 days ago in west London — were known to have been suffering from underlying health problems.

Pregnant women are at increased risk of contracting any infection because their immunity is suppressed to ensure that their body does not reject their baby.

Experts believe that most cases of swine flu would not harm the mother or foetus, but rare cases could lead to premature labour or miscarriage or cause birth defects.