Background
The narrative surrounding women’s reproductive health has shifted from a medical model to an emphasis on reproductive well-being over different life-stages. We developed and piloted a tracker survey for monitoring women’s reproductive health and well-being in England, recruiting respondents online. This paper reports on the success of the online recruitment strategies in achieving a sample proportionally representative of the England general population.

Methods
Recruitment was through Facebook and Instagram advertisements and dissemination through Twitter and a blog. At the end week one, the sample was reviewed and compared to the 2011 Census England population. From week two, recruitment targeted under-represented groups. Key data were compared with prevalence estimates from the Third National Survey of Sexual Attitudes and Lifestyles (Natsal-3).

Results
Between 1 July-17 August 2021, 13,962 people initiated the online survey, with 11,578 completing it. Numbers were low initially, but peaked at 1700 survey initiations per day after increasing the daily advertisement budget on day seven. At the end of week one, minority ethnic groups and people without a degree or equivalent were under-represented. From week two, we altered the advertisement settings to show to people whose profile indicated they were a ‘high school leaver’ had ‘up to some high school’, worked in industries that do not typically require a degree or lived in local authorities with a high proportion of ethnic minority residents. This had a modest effect, with the final sample short of proportional representation in terms of ethnicity and education but close in terms of region and age. Compared to Natsal-3, we found consistency in the proportion of respondents reporting an abortion and a live birth in the last year, however, the proportion of our sample reporting ever having experienced infertility was significantly higher than in Natsal-3, as was the proportion of ‘planned’ pregnancies in the last year.

Conclusions
It is possible to recruit large numbers of respondents online, relatively quickly, to complete a reproductive health survey. This will be valuable to track reproductive health and well-being at a national level over time. More work is needed to understand reasons for non-response among under-represented groups.