A study, published in the advance online edition of the journal Human Reproduction this week, warns women that the availability of assisted reproduction techniques cannot compensate for 'waiting too long to start a family'. Women who delay trying to have their first child until they are 35 and then find they have trouble conceiving naturally, cannot depend on assisted reproduction to make up fully for the loss of natural fertility after that age, the study says.
The research, undertaken by Professor Henri Leridon from the French Institute of Health and Medical Research (INSERM), was carried out in order to provide women with more efficient family planning advice and more precise information about the potential risks of postponing childbirth. In several European countries the average age for a woman to have her first child is already around 30 years old. The research used a computer programme, which calculated the likelihood of having a baby following natural conception if a woman started trying to conceive at ages 30, 35 or 40. This was compared with the likely success rate if the same women turned to IVF after either four, three or two years respectively and assuming that each woman would try IVF twice. The computer combined the monthly probabilities of conceiving, the risk of miscarriage and the increased probability of becoming permanently infertile through age.
The results showed that about three-quarters of women who try to conceive their first child at the age of 30 would have a successful pregnancy within one year. This figure drops to about two-thirds for those women starting at 35 and to 44 per cent for those starting at age 40. The study also showed that four years after first trying to conceive, 91 per cent of 30 year-olds, 84 per cent of 35 year-olds and 64 per cent of 40 year-olds would be successful, without the need for IVF. But, said Leridon, ' if women of 30 at first attempt at pregnancy turn to assisted reproductive technology (ART ) after four years of trying unsuccessfully, women of 35 turn to ART after three years of trying and women of 40 turn 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 attempt at pregnancy from age 30 to 35 and less than 30% after postponing from 35 to 40 years.'
Professor Leridon said that the message from the study was for women aged under 35 to 'be patient' when trying for their first child: ' Even if you fail to conceive within a year your chances of conceiving subsequently are still substantial', he said. But, he warned, women aged 35 or over should 'be impatient', and try IVF sooner. While the chance of conceiving naturally is still significant, he said, if this fails, 'ART will not fully compensate you for the years, and the chances of conceiving, that you have lost'. Generally, he said, 'do not wait too long before consulting for infertility, because the effectiveness of medical techniques is also decreasing as you grow older'.