E-cigarette use (vaping) and cigarette smoking are associated with reduced markers of ovarian reserve: a cross-sectional study of 16,087 women

BACKGROUND: E-cigarette use (vaping) is rapidly increasing among women of reproductive age, with an estimated one in five women aged 15-45 now using e-cigarettes in England. Despite being promoted as a safer alternative to cigarettes, the reproductive health consequences of e-cigarettes remain poorly understood, despite products being on the market for 2 decades. This study aimed to investigate the association between e-cigarette use, cigarette smoking, and two hormonal markers of ovarian reserve in women of reproductive age. METHODS: A cross-sectional analysis was conducted using data from 16,087 women aged 18-45 who accessed a private reproductive hormone testing service between 11/2022 and 02/2025. Women with pre-existing reproductive health conditions (including PMOS, endometriosis, POI, and hypothalamic amenorrhoea) and those using hormonal contraception were excluded, ensuring a reproductively healthy population for analysis. Self-reported vaping and smoking were primary exposures, captured as never, former, occasional, or current use. Serum AMH and FSH were measured via standardised immunoassay from capillary blood samples. Multiple linear regression with log-transformed outcomes was performed, adjusting for age, BMI, and ethnicity. Vaping and smoking were modelled simultaneously to account for overlap between the two behaviours. RESULTS: Current vaping was associated with 5.6% lower serum AMH compared to never-vapers (p=0.023), with no significant association observed for FSH. Current cigarette smoking was associated with a 9.4% reduction in AMH (p=0.005) and a 7.7% increase in FSH (p<0.001). Neither occasional nor former vaping or smoking was significantly associated with either marker. Sensitivity analyses excluding dual users of tobacco and e-cigarettes (n=64, 0.4% of sample) and excluding all former users produced consistent results. No significant interaction between smoking and vaping status was detected (p=0.271 for AMH; p=0.244 for FSH). CONCLUSIONS: In this large study of reproductively healthy women, current vape use was independently associated with lower AMH, a commonly used marker of ovarian reserve, after adjustment for smoking status and relevant confounders. These findings warrant further investigation, particularly given the widespread and growing use of e-cigarettes among women of reproductive age.