PROOF © 2018 E. Schweizerbart’sche Verlagsbuchhandlung, 70176 Stuttgart, Germany www.schweizerbart.de DOI: 10.1127/anthranz/2018/0845 0003-5548/2018/0845 $ 0.00 Anthropol. Anz. Article J. Biol. Clin. Anthropol. Published online April 2018 Maternal mortality, marital status and bone mineral density in young women from the Coimbra identified skeletal collection Francisco Curate 1,2,3, * and Ana Tavares 4 1 Research Centre for Anthropology and Health, Department of Life Sciences, University of Coimbra, Portugal 2 Laboratory of Forensic Anthropology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal 3 Interdisciplinary Center for Archaeology and Evolution of Human Behavior, University of Algarve, Faro, Portugal 4 Department of Women and Children, Cascais Hospital – Dr. José de Almeida, Cascais, Portugal * Corresponding author: fcurate@uc.pt; franciscocurate@gmail.com; ana.tavares.lopes@gmail.com With 1 figure and 5 tables Abstract: In contemporary populations, pregnancy and lactation are usually followed by transient bone loss. The observa- tion of reduced bone mass in young females from archaeological sites has sometimes been interpreted as an outcome of reproductive stress. In order to evaluate the overall effect of reproductive dynamics on bone mass in a historical skeletal sample, bone mineral density (BMD) at the proximal femur was assessed by dual-energy X-ray absorptiometry in 78 young women (17–39 years) from the Coimbra Identified Skeletal Collection. BMD was compared within the skeletal sample (“maternal deaths” [ICD – 10: chapter XV] vs. “other causes of death”, and “married/widowed women” vs. “single women”). Results revealed that mean BMD differences among groups are non-significant, suggesting that a strict reproduc- tive interpretation of premature bone loss in young women from archaeological contexts is not sustained by empirical evidence. Bone mass in young women from archaeological sites should be interpreted as a complex trait stemming from the interplay between reproductive factors, genetics, nutrition, physical activity, and age at menarche. Keywords: BMD; reproductive patterns; bone loss; reference skeletal collections Introduction Throughout pregnancy and breastfeeding, significant changes take place in the maternal calcium (Ca) homeosta- sis and bone mineral metabolism to satisfy the Ca needs of the fetus and the neonate (Namgung & Tsang 2003, Møller et al. 2012). Maternal Ca homeostasis is mostly affected dur- ing the last trimester of pregnancy and the ensuing lactation cycle, when calcium requirements surpass those observed in the early stages of pregnancy (Agarwal & Stuart-Macadam 2003; Ulrich et al. 2003). The maternal skeleton struggles to adapt to the demand of Ca and other minerals, which are transferred through the placenta to mineralize the develop- ing fetal skeleton. Likewise, the growing requirements of calcium during breastfeeding also appeal for an adjustment of the bone mineral homeostasis in the lactating woman (Agarwal 2008). Pregnancy typically implicates a high bone turnover, with resorption anteceding formation. Bone remodeling uncouples during the first and second trimesters, with a peak in bone resorption in the last trimester (Ulrich et al. 2003). As such, bone mass can decrease during pregnancy, espe- cially at sites rich in trabecular bone, such as the trochan- ter or the lumbar vertebrae (Allali et al. 2007; Ulrich et al. 2003). Notwithstanding, hormonal regulatory mechanisms and metabolical adaptations in the maternal body oppose to bone loss during pregnancy by retaining the circulatory Ca in surplus, increasing intestinal absorption, and decreasing renal excretion of calcium (Namgung & Tsang 2003; Ritchie et al. 1998). Moreover, bone mass can escalate due to higher estrogen levels in late pregnancy and the increased bone loading associated with weight gain during gestation (Cure- Cure et al. 2002). Other factors, like physical activity, body mass and smoking habits, can influence bone mass during pregnancy, reducing or increasing it (Karlsson et al. 2005; To & Wong 2012; Jang et al. 2016; Wei et al. 2017). The effect of gestation upon the maternal skeleton is still not fully understood, with different epidemiological studies showing conflicting results about the overall gain or loss of bone mass during pregnancy. Nevertheless, most of the stud- ies have found that bone mineral density (BMD) decreases in response to the transfer of calcium to the skeleton of the developing fetus (Ritchie et al. 1998; Karlsson et al. 2005; Kraemer et al. 2012; Møller et al. 2012).BMDdecline during eschweizerbart_xxx