Objective To discuss and conduct an empirical investigation of the influence of eldercare-childcare integration services on the fertility intentions of women of childbearing age because strengthening women’s fertility intentions is a fundamental way of facilitating the long-term balanced development of the population.Methods Based on demographic census data of women of childbearing age in Ningbo China in 2023, the study employed a logit model and the KHB decomposition method.Results Eldercare-childcare integration services have significant positive effects on the fertility intentions of women of childbearing age, particularly women from non-only-child families and working outside the civil service. According to mechanism analysis, positive expectations for marriage and health improvement are internal mechanisms for the eldercare-childcare integration services to promote the fertility intentions of women of childbearing age. The standard regression results remained true after overcoming endogeneity by a robustness test and PSM (propensity score matching).Conclusion The study recommends optimising fertility-support policies, strengthening the systematic supply of eldercare-childcare integration services, and facilitating long-term balanced populations based on well-being guarantees for women of childbearing age.