Professor Henri Leridon, a demographer from the French Institute of Health and Medical Research (INSERM) and the National Institute for Demographic Studies (INED), reports in Europe's leading reproductive journal Human Reproduction that, while the chances of rapid conception were still significant for women over 35, if they failed to become pregnant spontaneously, assisted reproduction could not fully compensate for the lost years.
He reached his conclusion after using a computer simulation model to study the odds on achieving a live birth naturally if a woman started trying to conceive at ages 30, 35 or 40 compared with the success rate if they turned to assisted reproduction technologies (ART) after four, three or two years respectively and assuming two attempts at IVF.
The complicated computer simulation combined the monthly probabilities of conceiving, the risk of miscarriage and the probability of becoming permanently sterile through age.
"What it showed was that, under natural conditions, three-quarters of women starting to try to conceive at the age of 30 will start a successful pregnancy within one year. Two-thirds of those starting at 35 will be successful within one year and 44% of those starting at age 40 will succeed within one year. Four years after trying to start to conceive, 91% of 30 year-olds, 84% of 35 year-olds and 64% of 40 year-olds will have been successful.
"But, if women of 30 at first attempt at pregnancy turn to ART after four years of trying unsuccessfully, women of 35 turn to ART after three years of trying and women of 40turn to ART after two years of trying, then we find that ART will make up for only half of the births lost by postponing a first
Contact: Margaret Willson
European Society for Human Reproduction and Embryology