Britain's abortion laws, considered among the most liberal in Europe, came under scrutiny Tuesday with conservative parliamentarians asking for a cut in the 24-week upper legal limit for terminations to 20 weeks or less, the dpa reported.
The parliamentary debate on abortion is part of a current overhaul of Britain's Human Fertilization and Embryology Bill, which has already seen radical changes in the laws governing embryo and stem cell research.
If motions to reduce the abortion limit from the current 24 weeks were to be supported in a vote Tuesday evening, they would mark the first major change in abortion legislation in Britain since 1990, when the limit was cut from 28 to 24 weeks.
The 24-week limit is double that of France and Germany, and six weeks later than Sweden and Norway, but the same as in the Netherlands.
Pro-life campaigners argue that medical advances have meant that survival rates for babies born between 22 and 25 weeks had risen from 32 per cent in 1981 to 71 per cent in 2000.
But other research has shown no has found no improvement in "viability rates" for babies born before 24 weeks.
Pro-choice campaigners also point out that only 1.5 per cent of the annual 200,000 abortions in Britain are carried out after 20 weeks of pregnancy.
Britain's Medical Association (BMA), the biggest doctors' association, has come out in favour of keeping the 24-week limit, as has Gordon Brown, the Labour Prime Minister.
"The medical evidence has not changed and that is why I will support the 24 weeks," Brown said ahead of the vote Tuesday.
But Conservative member of parliament (MP) Nadine Dorries, who initiated a motion to cut the time limit to 20 weeks, said action was needed to reduce the fast rising number of terminations in Britain.
Previous attempts to force a vote on lowering the abortion limit have been defeated in parliament. But this time, MPs have been given a free vote, increasing the chance that members will stay away or abstain.
The vote was expected at around 2100 GMT.