Trends of low birth weight among timely birth and association with maternal age
Irisa Zile (LV), Inguna Ebela (LV), Valdis Folkmanis (LV), Ingrida Rumba-Rozenfelde (LV)
[Zile] The Centre for Disease Prevention and Control of Latvia, [Ebela] Faculty of Medicine, Department of Paediatrica, University of Latvia, [Folkmanis] Faculty of Medicine, Department of Paediatrica, University of Latvia, [Rumba-Rozenfelde] Faculty of Medicine, Department of Paediatrica, University of Latvia
Background. Maternal age has been widely reported to influence pregnancy outcome. Babies with low birth weight (LBW) are at increased risk. Objective. To examine trends in LBW by maternal age in timely births and assess the risk factors. Materials and Methods. Data source: population-based Medical Birth Register, 2000-2013. All timely live births (≥37th gestational week (GW)) with LBW (≤2499g) (n=3972) were included. LBW rates (LBWR) by maternal age (≤19; 20-34; ≥35 years) and OR were calculated (reference category: 20-34 years). Time trends were analysed by calculating rate ratios (RR), comparing rates (2000 – 2006 with 2007 – 2014). Results. The overall LBWR in timely births showed slight reduction (p<0.01) by 8% (2000-2006/2007-2014). LBWR decreased to 13.8/1000 (95%CI 13.2-14.3) from 15.1/1000 (95%CI 14.4-15.7), RR is 0.9/1000 (95%CI 0.8-1.0).There was a slight increase in LBWR for mothers ≤19 years, RR 1.2/10000 (p>0.05) (95%CI 1.1-1.5), statistically significant reduction in age group 20-34 years (p<0.05) RR 0.9/1000 (95%CI 0.8-1.0) and ≥35 years (p<0.01) RR 0.8/1000 (95%CI 0.7-0.9). The higher odds of LBW in timely births for younger mothers was associated with intrauterine growth restriction (IUGR) (OR=1.5; p<0.01), preeclampsia (OR=1.7; p<0.05), gestational hypertension (OR=1.9; p<0.05) and late first antenatal visit (after 12th GW). In maternal age group ≥35 years higher risk for LBW were observed just with one indirect factor - late registration for antenatal care (OR=1.7; p<0.001). Conclusions. The overall LBWR in timely births showed slight statistically significant reduction (p<0.01) over the study periods. Young maternal age had increased risk with LBW associated with IUGR, preeclampsia and gestational hypertension. Public health programs should be targeted towards improving antenatal care screening and close monitoring including maternal age.