Monaz: Hello, I'm Monaz Mehta, editor in the Cochrane Editorial and Methods department. Cochrane Reviews cover a wide range of interventions to help couples with infertility or subfertility to conceive, and these are updated to take account of new evidence or introduce new review methods. One of the reviews, looking at preconception lifestyle advice for people with infertility, was updated for the first time in April 2021 and we asked lead author, Tessy Boedt from the Department of Chronic Diseases and Metabolism at KU Leuven in Belgium to tell us more.

Tessy: Infertility affects more than 45 million couples worldwide, placing a significant burden on individuals, families, and the wider community.
Some of the factors that may affect fertility are being overweight or obese, having a high fat/high sugar diet, a lack of physical activity and smoking; and infertile couples might be provided with advice to try to improve these lifestyle factors. However, there is a lack of guidance on what advice should be given and how effective it is at improving an infertile couple’s chances of conceiving a healthy baby. With this in mind, our review seeks to determine whether preconception lifestyle advice improves fertility outcomes, including live birth and miscarriage. We also looked at the impact of the advice on the lifestyle of couples with infertility.
We found 7 studies including 2130 women and men with infertility, but only one of the trials included male partners. Three studies tested preconception lifestyle advice that covered a combination of topics while the other four evaluated advice on a single topic, such as weight, smoking or alcohol consumption. Overall, the quality of the available evidence was low to very low, because of poor research methods and imprecision and inconsistency in the findings.
Compared to routine care, preconception lifestyle advice that covered a combination of topics, such as diet, folic acid supplementation and smoking and alcohol cessation did not show an effect on live birth and none of the studies reported on adverse events or miscarriage. Also, because of the very low quality of the evidence, we are uncertain if the advice changed the couples’ lifestyle behavior.
Turning to the trials that tested advice about a single topic, we are uncertain whether preconception lifestyle advice on weight for women with infertility and obesity affects live births, or adverse events and miscarriage. However, it might slightly reduce the body mass index, or BMI, of women with obesity and infertility compared to routine care. In regard to providing preconception lifestyle advice on alcohol intake and smoking, there is too little evidence to know if this is better or worse than routine care. 
In summary, the available evidence and its quality is insufficient to draw firm conclusions on the effect of preconception lifestyle on fertility outcomes or lifestyle factors. Unfortunately, therefore, we are not able to provide clear guidance for clinical practice. However, the updated review does highlight the ongoing need for high‐quality randomized trials, which investigate preconception lifestyle advice covering a combination of topics to determine its effectiveness and safety in women and men with infertility.

Monaz: If you would like to read the current review and watch for further updates should those trials be done, it’s available online. Just go to Cochrane Library dot com and search ‘preconception lifestyle advice’ to find it.