Socio-economic, demographic and obstetric risk factors for late fetal death of unknown etiology in Lithuania:: a case-referent study

Background. The purpose of this study was to evaluate the association between third trimester unexplained prelabor fetal deaths and various socio-econonmic, demographic and obstetric factors in Lithuania. Methods. A case-referent study on 58 women with third trimester fetal death and 116 women with live fetus at term was carried out. Inclusion criteria for women in the first group (cases) were: prelabor fetal death of unknown etiology, singleton pregnancy >26 weeks of gestation and intact fetal membranes. For each case two referent women were recruited, admitted during the same period in active phase of labor at term (>37 weeks of gestation) with intact fetal membranes and fetus alive. Data were obtained by interview, anthropometry and by reviewing the medical records. Several potential socio-economic, demographic and obstetrical risk factors for unexplained fetal death were investigated. Results. Univariate analyses determined several factors that were associated with fetal death of unknown etiology: low educational level, single marital status, low income, etc. After secondary logistic regression analysis only three independent variables remained significantly associated with otherwise unexplained stillbirth: small for gestational age fetus (OR 29.6; 95% CI 6.2-141.6), low income (OR 7.4; 95% CI 3.1-17.6), and maternal white blood cell count more than 16,000/mm(3) (OR 5.4; 95% CI 1.4-21.6). Body mass index, smoking, occupation of women and other evaluated parameters were not confirmed to be significant risk factors. Conclusion. Small for gestational age fetus, low income and elevated maternal white blood cell count are factors significantly associated with late prelabor fetal death in Lithuania.