Association of gestational anemia with pregnancy conditions and outcomes: A nested case-control study

BACKGROUND: Gestational anemia is a serious public health problem that affects pregnant women worldwide. Pregnancy conditions and outcomes might be associated with the presence of gestational anemia. This study investigated the association of pregnancy characteristics with anemia, exploring the potential etiology of the disease. AIM: To assess the association of pregnancy parameters with gestational anemia. METHODS: A nested case-control study was conducted based on the Chinese Pregnant Women Cohort Study-Peking Union Medical College Project (CPWCS-PUMC). A total of 3172 women were included. Patient characteristics and gestational anemia occurrence were extracted, and univariable and multivariable logistic regression models were used to analyze the association of pregnancy parameters with gestational anemia. RESULTS: Among the 3172 women, 14.0% were anemic, 46.4% were 25-30 years of age, 21.9% resided in eastern, 15.7% in middle, 12.4% in western 18.0% in southern and 32.0% in northern regions of China. Most women (65.0%) had a normal prepregnancy body mass index. Multivariable analysis found that the occurrence of gestational anemia was lower in the middle and western regions than that in the eastern region [odds ratio (OR) = 0.406, 95% confidence interval (CI): 0.309-0.533, P < 0.001)], higher in the northern than in the southern region (OR = 7.169, 95%CI: 5.139-10.003, P < 0.001), lower in full-term than in premature births (OR = 0.491, 95%CI: 0.316-0.763, P = 0.002), and higher in cases with premature membrane rupture (OR=1.404, 95%CI: 1.051-1.876, P = 0.02). CONCLUSION: Gestational anemia continues to be a health problem in China, and geographical factors may contribute to the situation. Premature birth and premature membrane rupture may be associated with gestational anemia. Therefore, we should vigorously promote local policy reformation to adapt to the demographic characteristics of at-risk pregnant women, which would potentially reduce the occurrence of gestational anemia.