Prevalence of anaemia, risk of haemoconcentration and risk factors during the three trimesters of pregnancy

Objective: To evaluate the prevalence of anaemia and the risk of haemoconcentration and its risk factors during all 3 trimesters of pregnancy in women in a Mediterranean area in the south of Europe. Material and methods: Longitudinal study of 11,259 women whose pregnancies were monitored at primary care centres between 2007 and 2012. The computerised clinical histories of all the pregnancies were used to collect haemoglobin (Hb) data for each trimester. The histories also provided information on the age of the mother, her socioeconomic status, the presence of obesity, tobacco use, type of pregnancy, and number of previous pregnancies and births. Anaemia was defined as Hb < 110 g/L in the 1st and 3rd trimesters of pregnancy and Hb < 105 g/L in the second. The risk of haemoconcentration was defined as Hb > 130 g/L in the 2nd and 3rd trimesters of pregnancy. Results: The prevalence of anaemia increased from 3.8% in the first trimester to 21.5% in the 3rd trimester. Around 10% of the women had Hb > 130 g/L during the 3rd trimester. Having children previously and/or being younger than 20 increased the chances of anaemia (Adj. OR: 1.4; 95% CI: 1.1-1.9), but being older than 34 increased the chances of Hb > 130 g/L (Adj. OR: 1.3; 95% CI: 1.1-1.5). Conclusion: The increased prevalence of anaemia is a moderate public health problem. Understanding the factors that influence these problems may help improve the guidelines regarding the use of iron supplements.