MPs are considering cutting the abortion time limit as part of the Human Fertilisation and Embryology Bill.
The 24-week upper limit was set in 1990 because it was the point at which the foetus was considered viable. Only 1.5% of the 200,000 UK abortions each year take place after 20 weeks.
Here, two women tell their stories of late-term abortion and extremely premature birth.
KAREN DUGDALE, ABORTION AT 21 WEEKS
I went for my 20-week anomaly scan thinking everything was perfectly fine with the baby. We were told at that particular scan there were a range of abnormalities affecting our baby.
We were then given the option of terminating or continuing the pregnancy. We felt at that point in our lives, with our own personal circumstances, we weren't able to continue with that pregnancy.
It's not an easy decision. Abortion is horrible at eight, 24 or 28 weeks. It's a messy business but unfortunately life doesn't always fit into little pigeon holes. It's not always perfect.
We found the decision very difficult, as most women in that situation do - and not just for abnormalities, for a range of personal and very individual circumstances.
You don't know about late termination, for whatever reason, unless you're faced with having to go through one. You don't want to get involved in hearing about it because it is messy, it's horrible, it's not a nice situation.
Yes, I may have been included in that small group of women under ground E [of the Abortion Act], where abnormality allows you to have late abortion, but there are a whole raft of reasons why women present late for abortion and it really does just affect a very small number of us.
There is anecdotal evidence that doctors want almost a tick list of foetal abnormalities, so some would qualify, some wouldn't. You're going down a slippery path here. Every person's reason for wanting a late termination is valid to them and their circumstances.
The foetal abnormality issue shouldn't be taken separately from other women presenting late for termination.
LIZ GODDARD, SON WILL BORN AT 22 WEEKS GESTATION
I was having a perfectly normal pregnancy up until about 22 weeks when things went wrong and Will was born prematurely in hospital.
Because he was [born] before... 24 weeks, there was no offer of treatment, they were very certain that he was going to die. So he was just left with me, I was holding him in the maternity suite.
They said he would be alive for maybe 10 minutes, maybe an hour. Time went on and after about seven hours they did take him into the special-care baby unit, but only to keep him comfortable.
There was no suggestion that he would be treated, because he didn't fit within that 24 week date.
He was about 36 hours old when he started finally to show signs of distress, and by that time the hospital staff had met, discussed the case and decided they would offer him treatment because he had lived for 36 hours unaided and clearly had potential.
At that point they offered to treat him if that's what I wanted - which I did - and from that point on they treated him as they would any other premature baby.
Now, he's absolutely fine. He's close to the top of his class at school and interested in all sorts of things that 10-year-old boys are interested in.
Early on, the first three, four years, he did have a few problems, developing late. By the time he started school, he had completely caught up.
The limit needs to be changed to below 22 weeks. Once a child has potential for life, the rights of the child need to take precedence over the rights of the mother. If Will could survive, so can others.
The current guidelines say that if a termination is going to happen between 22 and 24 weeks, steps have to be taken to ensure the baby is born dead.
Those guidelines are there because at 22, 23 weeks the babies would be born alive and if we were in a situation where we were killing them after birth, there would be uproar. So they're killed first, and then delivered and that's called a late-term abortion.
We're talking fairly small numbers here. Probably statistically the evidence isn't significant in terms of the increase in survival rates for 22 and 23-week-old babies.
However, they are surviving and to those babies and their families it's extremely significant and we have to be careful about statistics in these issues.