Persistent estrus caused by elevated estrogenic activity, either due to endogenous estrogens (e.g., in polycystic ovary syndrome) or due to exogenous substances.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 752 (https://doi.org/10.1515/pac-2015-1202)