Abstract Objective: Using endometrial secretion analysis, we assessed whether altered inflammatory cytokine levels can be detected in the uterine environment in asthma patients, thereby providing a possible cause of reduced fertility in asthmatics. Methods: Forty-four unexplained infertile women (aged 28-44) underwent asthma and allergy testing, questionnaires, endometrial secretion and blood samples in the mid-secretory phase of the menstrual cycle (day 19-23) during assisted reproduction. Differences in cytokines and growth factors were analyzed. Results: Mean log-VEGF in uteri was lower in asthma patients compared with controls (2.29 versus 2.70, p = 0.028). This was mainly due to lower values of VEGF among women with non-atopic asthma compared with women with atopic asthma (1.86 versus 2.72, p = 0.009) and with healthy controls (1.86 versus 2.70, p = 0.01). Asthma treatment status had no effect on VEGF levels in uteri. Serum high sensitivity CRP was negatively correlated with VEGF in endometrial secretions. No other significant correlations were observed between peripheral blood values and markers found in utero. Conclusion: Asthma is associated with lower values of VEGF in uterine endometrial secretions, which might affect the receptiveness of the endometrium and thereby increase time to pregnancy. The effect appears to be associated with non-atopic asthma with general increased systemic inflammation.