Abstract Study question Does ethnicity play a role in fertility assessment-seeking behaviour of Black women in the United Kingdom (UK)? Summary answer Black women approach an at-home reproductive health and fertility assessment service later in their fertility journey than White women. What is known already Evidence from the Human Fertilisation and Embryology Authority (HFEA) shows that Black patients access fertility care two years later than the national average in the United Kingdom (UK) (36.4 vs 34.6 years). Additionally, previous research has shown different prevalences of reproductive health conditions associated with infertility amongst Black women, such as fibroids and tubal occlusion. In combination with delayed access to fertility care, this may contribute to the lower live birth rates seen in Black patients in the UK. Study design, size, duration A retrospective observational study conducted on 143,251 Hertility Health users who completed a virtual health assessment between September 2020 and January 2023. The health assessment collected self-reported data on age, ethnicity, pre-existing diagnoses of reproductive health conditions, whether they were actively trying to conceive (TTC) and the length of time they had been actively TTC. Participants/materials, setting, methods A total of 25.9% users (n = 37,170) indicated they were TTC. The majority of those TTC self-identified as White (82.9%), followed by Asian (7.4%), Mixed (3.6%), Black (4.6%) and ‘Other’ (1.5%). Summary statistics (mean ± SD and %) regarding age and prevalence of pre-existing conditions of users TTC have been reported. Additional statistical analysis of the associations of time spent TTC between ethnicities was conducted via Chi-squared test (χ2); p values <0.05 were considered significant. Main results and the role of chance A significant relationship was observed between time spent TTC and ethnicity; the strongest association was observed between Black and White users χ2 (16, n = 34,706)=120, p < 0.0001). Comparison of time spent TTC, and average age showed that fewer Black women undertook the virtual health assessment at < 6 months of TTC than White women (29.3%, n = 469 vs 34.1%, n = 9820) at a moderately older age (31.3±6.5 years vs 29.8±5.7 years). A higher percentage of Black women were TTC for >5 years compared to White women (14.2%, n = 227 vs 8.8%, n = 2544). Additionally, Black women at this time point were approximately four years older than White women (36.9 years ± 6.0 years vs 33.0 ± 5.1 years). Secondary analysis of the prevalence of reproductive health conditions associated with infertility indicated that 20.1% (n = 133) and 22.5% (n = 149) of Black women had a preexisting condition at < 6 months and >5 years of TTC, respectively, vs 22.6% (n = 1363) and 19.2% (n = 1158) of White women in the corresponding TTC length groups. Limitations, reasons for caution As the virtual health assessment data was self-reported, there is a risk of recall bias and false reporting. Data was stratified via the main ethnicities and did not take the heterogeneity within ethnic groups or mixed ethnicities into account. Wider implications of the findings This data suggests that Black women approach fertility testing services later than White women, which may contribute to the disparities between pregnancy outcomes in the UK and cannot fully be accounted for by preexisting diagnoses associated with infertility. Further investigations are needed to outline the underlying reasons for this. Trial registration number not applicable