The study, presented virtually at ENDO 2021, showed that the lifestyle intervention, called the Fit-For-Fertility (FFF) programme, is a cost-effective alternative to the usual standard of care for women with obesity seeking fertility treatments.

"Our study shows that the FFF programme can significantly improve the pregnancy rate, especially the spontaneous pregnancy rate when no fertility treatments are required, as well as the live-birth rate," said lead researcher Matea Belan from the University of Sherbrooke in Canada.

Lifestyle changes and a moderate weight loss of 5 per cent to 10 per cent of a woman's initial weight have been shown to improve the odds of a pregnancy in women with obesity and infertility, the researcher said.

For the study, the researchers recruited 130 women receiving treatment at a fertility clinic, and randomly divided them into two groups.

The first group had access to the Fit-For-Fertility programme alone for the first six months of their participation, and in combination with fertility treatments if no pregnancy occurred after six months.

The programme included individual sessions with a nutritionist and a kinesiologist every six weeks. Women in the FFF group were also asked to follow at least once each one of the 12 group sessions, which included a 45-minute workshop on topics regarding nutrition, lifestyle changes and lifestyle habits, followed by a 45-minute session of initiation to different types of physical activity, including walking, circuit training, step workout and others.

In the second group, the control group, women had access to the fertility treatments from the outset but did not take part in the FFF programme.

Of the 108 women who completed at least six months of the study, or became pregnant during the first six months, the FFF programme generated a difference of 14.2 per cent points in the live-birth rate (51 per cent for the FFF group and 36.8 per cent for the control group).

The spontaneous pregnancy rate (pregnancy without any fertility treatments) was 33.3 per cent in the treatment group, compared with 12.3 per cent in the control group.