Elizabeth Adeney, who owns a holiday apartment in a retirement village where children are banned, insists she is not too old to have a child despite warnings from fertility experts, The Daily Telegraph reported.
They say she is simply too old to be a mother.
The childless divorcee travelled to the Ukraine for IVF treatment and is planning to give birth at a clinic in Cambridge in the next month.
She will be nearing 80 when the child becomes a teenager.
But her choice was criticised by IVF expert Professor Severino Antinori who claims the child could suffer psychological problems.
Prof Antinori, who helped 62-year-old Briton Patricia Rashbrook give birth three years ago said he was shocked at the prospect of Ms Adeney having a child
"I respect the choice medically but I think anything over 63 is risky because you cannot guarantee the child will have a loving mother or family," he said.
"It is possible to give a child to the mother up to the age of 83 but it is medically criminal to do this because the likelihood is the child will lose his mum and suffer from psychological problems."
The NHS does not recommend fertility treatment for the over-40s while most British clinics will not offer IVF treatment to women over the age of 50.
But Mrs Adeney, of Lidgate, near Newmarket claims she feels 39 inside and is fitter than women who are a third of her age.
"I have young girls working for me in my factory and I`m fitter than half of them," said Mrs Adeney, who runs a manufacturing business near her home and will be 67 in July.
"I don`t have to defend what I`ve done. It`s between me, my baby and no-one else.
"It doesn`t interest me that I`m going to be the oldest mum in the country."
She added: "I don`t expect anyone else to understand it. I`m not even asking them to.
"I`m amazed that the fact I am having a baby at all is interesting to anyone."
She said that sometimes she felt as young as 39, adding: "It`s not my physical age that`s important - it`s how I feel inside."
Residents at the Grosvenor Square retirement village in Cape Town, South Africa, were amazed to learn she was pregnant.
Friend Alan Forrester said: "It was quite a shock when she told me she was having a baby. There will be quite a few raised eyebrows at Grosvenor Square.
"It`s all pretty conservative here. You don`t expect things like that to happen here.
"I hope she doesn`t suffer any complications."
"We all know it`s more of a risk as you get older."
Staff have agreed to bend house rules and allow Mrs Adeney to stay in the flat with her baby when she visits.
Friends said she keeps fit, swims regularly, does not smoke and watches her diet and has wanted a baby for a long time, trying IVF unsuccessful a few years ago.
She is separated from Robert Adeney, the former chairman of London luxury leather and hunting goods firm Swaine Adeney Brigg and Sons – which supplied horse whips to the Royal Family.
Last year couples seeking IVF treatment are to be warned for the first time that their children have a higher risk of suffering birth defects, disability and life-threatening conditions.
The alert by the Human Fertilisation and Embryology Authority (HFEA), the government`s watchdog on fertility issues, followed a US study indicating test-tube babies are at a 30 per cent greater risk of suffering from conditions such as cleft palates and defects with heart valves and the digestive system than children conceived naturally.
MumsNet users who were asked to comment for The Daily Telegraph had mixed reactions to the news.
Didoreth wrote: "A woman of 66 who can sustain a healthy pregnancy to term, as this woman obviously can, would have a longer than average life expectancy. She`s got a good chance of living till she`s 90, or at least of seeing her child into its twenties."
But Maggie Beauregarde wrote: "If you want to swim upstream against mother nature then I`m not stopping you, or anybody else, but there are reasons why women usually stop having children beyond 40 plus."
And sparklycheerymummy added: "I just think what happens to the baby when it reaches 21 and its mother is 87 and if still with us probably needing care and looking after...... is that fair on a 21 year old: She may be healthy now but that baby is not going to have any support in adulthood is it?"