Vitamin D deficiency, pregnancy, and childbirth in early medieval Milan

This paper explores the burden of osteomalacia on pregnancy and childbirth through two cases from early medieval urban Milan. Two skeletons of female individuals with skeletal deformities and associated with 25–36 gestational weeks fetuses, excavated from the Ad Martyres and San Vittore al Corpo urban cemeteries and dated to the Early Middle Ages, were examined. Paleopathological and historical analyses were performed in a biocultural approach to investigate the impact of clinical complications and skeletal deformities on their daily life, the course of their pregnancy, and childbirth. The women showed severe skeletal deformities attributable to osteomalacia including scoliosis, reduced rib-neck angle, coxa vara, severe bending of the pelvic bones, protrusio acetabuli, and narrowed pelvic outlet. The condition and its biomechanical complications impacted the health of both mothers and fetuses, the quality of life of the women (i.e., gait alteration, difficult and limited mobility, compression of internal organs), as well as pregnancy outcomes. It is possible that both the mothers and fetuses died due to childbirth complications. Bioarchaeological cases of osteomalacia, pregnancy, and death during childbirth are excessively rare. This paper also provides insight into how maternal experiences and biocultural environments in early medieval Milan impacted childbirth outcome. The study of the Ad Martyres and San Vittore al Corpo necropolises is still ongoing and could provide further insight. Isotopic and paleogenomic analyses may shed more light into the factors that led to vitamin D deficiency in these women.