The cold, hard facts on getting pregnant after 35

By 44 or 45, most women can forget about having their own biological baby, even with IVF assistance.
By 44 or 45, most women can forget about having their own biological baby, even with IVF assistance. 

Halle Berry did it at 41. So did Nicole Kidman. Geena Davis had twins at the seemingly over-ripe age of 48. Has the slew of female celebrities giving birth after 35 meant that the rest of us now reason it's easy enough for us as well?

Just as we forget about the airbrushing that makes celebrities look dewy and flawless, do we conveniently ignore how fame and money often buy options: surrogacy (as in the case of Sarah Jessica Parker), adoption (Michelle Pfeiffer and her first child), or donated eggs (funnily enough, no celebrity has owned up to this one yet, to our knowledge)?

How hard is it to get pregnant once you hit 35 and beyond? Perhaps surprisingly, Dr Peter Illingworth has good news for 35-year-old women trying to have their first child. "At 35, their chance of having a child is very good, assuming there are no underlying problems," says Illingworth, president of the Fertility Society of Australia and medical director of IVF Australia.

Even so, he sees plenty of patients around that age who are desperately worried that they have missed the boat: "I can understand why they're nervous, especially if they're hoping to have more than one child, but I'm usually very positive for them."

The real danger age is 40, according to Illingworth - and by 44 or 45, most women can forget about having their own biological baby, even with IVF assistance. "Once a woman gets to 40, her fertility is about half that of a 33-year-old - but at 36 or 37, it's only a bit lower," he says.

A 35-year-old woman has a 30 to 40 per cent chance of a live-born child from an IVF cycle.

Translated into cold, hard statistics, a 33-year-old, with no underlying issues such as endometriosis or fibroids, has an 85 to 90 per cent chance of conceiving within 12 months, says Illingworth. By age 36 or 37, that has dropped to 70 per cent, then there is a steep decline at age 40, when her chances are only 45 to 50 per cent.

The reason is that females are born with all their eggs in their ovaries - typically about 400,000 - and they gradually ovulate them during each menstrual cycle. The remaining eggs age as the woman gets older, reducing their quality.

This, in turn, reduces their ability to be fertilised and divide properly, leading to a higher risk of chromosomal abnormalities and miscarriage. Men, in contrast, continue manufacturing new sperm.

This ageing of the eggs means that IVF success rates are also affected. Illingworth says a 35-year-old woman has a 30 to 40 per cent chance of a live-born child from an IVF cycle.

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At 36, her chances are 25 to 30 per cent and at 38, this drops to 20 to 25 per cent. By 40, her chances of a live-born child from an IVF cycle are only 15 to 20 per cent.

"It's certainly more nerve-racking for women aged 35 to 40 - the ones I see are conscious that time is running out for them," says Illingworth, adding that the reason most of his patients delay pregnancy is that they have only just met the right partner.

This story first appeared in Sunday Life magazine, in the Sun-Herald and Sunday Age.

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