One in 5 pregnancies experiences an adverse outcome, the most devastating of which is stillbirth. Current approaches to reducing stillbirth focus on preventative care at the end of pregnancy. While gains are being made in reducing the rates of term stillbirth, these approaches fail to target the 85% of stillbirths that occur in the preterm period and completely ignore pregnancy loss that occurs before 20 weeks. Stillbirth is also not a condition, but rather the result of a number of conditions and the product of a broader interplay of individual, biological, structural, cultural and social factors. The underlying aetiologies of stillbirth, miscarriage, preterm birth, fetal growth restriction and preeclampsia overlap and are generally attributed to placental dysfunction; the origins of that poor placental function are not fully understood. The endometrial environment into which the embryo implants and the placenta develop is fundamental to establishing the trajectory of pregnancy, yet our understanding of the endometrium’s role has been hampered by the inability to study it non-invasively. The study of menstrual fluid and menstruation has the potential to overcome this bottleneck, opening up new avenues to better understand and prevent adverse pregnancy outcomes across the continuum.