Several observational studies have suggested that women with endometriosis have a slightly increased risk for preterm birth. The cause seems to be related to factors associated with pathogenesis of endometriosis, such as inflammation, reactive oxygen species, progesterone resistance, and alterations in the junctional zone of uterus leading to the shallow invasion of the placenta and to preterm birth. But is this association firmly established? It is actually more an enigma than solid evidence. In October 2024, a new cohort study in Fertility Sterility is questioning this relationship. These results are a contrast to the findings of a meta-analysis published in January 2022, which itself conflicted with results of a French observational study published the following month, February 2022. It’s the perpetual problem and enigma of whether endometriosis is associated with PTB, or not! Listen in for details.