Health Minister Dawn Primarolo says the government does not believe there is sufficient scientific evidence to lower the legal abortion limit of 24 weeks.
She said nothing had persuaded the Department of Health that survival rates had improved for extremely premature babies born before that time.
The Pro-Life Alliance wants the upper limit for terminations to be cut.
But the British Medical Association says the number surviving at 24 weeks is still "extremely small".
Ms Primarolo was giving evidence to the Commons science and technology committee, which is looking at medical advances since the Abortion Act was passed in 1967 - rather than the ethical or moral issues associated with abortion time limits.
Abortion is seen as a "conscience issue" in Parliament so MPs are given a free vote on law changes rather than being directed how to vote by their party leaders.
The committee also questioned Fiona Adshead, deputy chief medical officer for England.
Ms Primarolo told MPs: "The Department of Health's view and the advice to me is that - and that's why there is no proposals from the government to amend the act - that the act works as intended and doesn't require further amendment at the present time."
She said 89% of abortions were carried out before 13 weeks and 68% before 10 weeks. The viability of babies born at 21 weeks was 0%, at 22 weeks 1% and 23 weeks 11%, she said.
"The medical consensus still indicates that whilst improvements have been made in care that at the moment that concept of viability cannot constantly be pushed back," she said.
In occasionally heated exchanges, Conservative MP Nadine Dorries, a former nurse, suggested that Ms Primarolo was committed to a liberalisation of the Act and perhaps a minister with a "fairer" view should be considering these matters.
Ms Primarolo said: "I am not here to discuss my personal views. I'm here as the minister to answer the questions the committee puts to me about the information the department has."
She said the Department of Health wanted to see abortions conducted as quickly as possible, but stressed that changes to the Act were down to the will of Parliament.
Ms Dorries pressed her to say whether she was content with the 24 week upper limit, when viability rates for babies born below that age were quite high in NHS hospitals where there were good neonatal units.
Ms Primarolo said: "The department's view is yes, that's what Parliament has decided and that's where we are. It's for the House to decide on that."
Labour's Graham Stringer asked if there was any way a woman seeking an abortion could find out if her GP was a conscientious objector opposed to the practice because this could result in a delay to her treatment.
The minister said if doctors were ethically opposed to abortion they should "follow the relevant professional guidance".
"We are not seeing that as an issue in the evidence that we have," she said.
Tory Dr Robert Spink asked what the Department of Health would define as a "seriously handicapped" baby under the Act and whether it was "comfortable" that children may be aborted because they have cleft palates.
Ms Primarolo said in what "would be very difficult circumstances we are prepared to take the advice from two doctors who understand the circumstances" and who would "make their best judgement".
Ms Dorries asked: "If the evidence shows that a foetus could feel pain at 20 weeks or less, would the department consider altering its guidelines or making amendments to the Act?"
Ms Primarolo said the department did not see a connection with the viability of a foetus, but it would continue looking at the issue through its research.
The minister also stressed that Parliament had decided that before an abortion could take place it required the signatures of two doctors.
Julia Millington, political director of the Pro-Life Alliance, said it appeared the government had not considered the "incredible work" being done by neonatal units across the world.
"The minister's failure to consider evidence of the vast improvement in the survival rates of babies born before the 24-week abortion time limit is staggering," she said.
Earlier, Lord Steel, the architect of the 1967 Abortion Act, said too many abortions were taking place and the procedure was now being used as a form of contraception.
He told The Guardian he was not persuaded that the 24-week limit should be cut, but called for better sex education and a debate on sexual morality to bring the numbers down.
Catholic and Church of England leaders have called for a reassessment of abortion's role in society, as the 40th anniversary of the Act is marked.
In an open letter Cardinals Cormac Murphy-O'Connor and Keith O'Brien accepted that abortion will not be abolished, but stressed that it "robbed everyone of their future".
The Archbishop of Canterbury, Dr Rowan Williams, warned that abortion was increasingly regarded as normal, rather than as a procedure of last resort.
According to the Department of Health, 193,000 abortions happened in England and Wales last year.
The Pro-Life Alliance says babies born at 24 weeks now have a much better chance of survival than when the Abortion Act was passed.
But the BMA says that, despite "very considerable" scientific advances, the number of babies born at 24 weeks and surviving is still "extremely small".
The issue of abortion will be aired again during debate on the Human Tissue and Embryos Bill next month.
When the Abortion Act was first passed the normal time limit for termination was 28 weeks, but this was lowered to 24 in 1990.