Early pregnancy anaemia tied to adverse outcomes

The presence of anaemia in the first trimester of pregnancy is associated with adverse outcomes, including blood transfusion and severe maternal morbidity, as reported in a study.

Researchers used nationwide insurance claims data and identified pregnant individuals without hereditary anaemias. Haemoglobin and haematocrit were used to determine anaemia in early pregnancy (before 14 weeks of gestation) and late pregnancy (at or after 24 weeks of gestation).

Pregnancy outcomes included pre-eclampsia, placenta previa, placental abruption, severe postpartum haemorrhage, blood products transfusion, caesarean birth, nontransfusion severe maternal morbidity, spontaneous preterm birth, medically indicated preterm birth, and small-for-gestational-age (SGA) birth weight.

Of the 73,586 individuals included in the analysis, 4.4 percent had anaemia in early pregnancy. Early pregnancy anaemia was associated with an increase in the risk of each outcome assessed, except for placenta previa. The greatest increase was observed for the risk of blood products transfusion (2.4 percent vs 0.8 percent; adjusted risk ratio [aRR], 2.45, 95 percent confidence interval [CI], 1.91–3.13).

In the group of individuals with early pregnancy anaemia and laboratory values in late pregnancy, anaemia persisted in 53.4 percent and resolved in 46.6 percent. Compared with individuals who had no anaemia in the first trimester of pregnancy, those with persistent anaemia had elevated risks of non-transfusion severe maternal morbidity (2.6 percent vs 1.1 percent; aRR, 1.64, 95 percent CI, 1.13–2.37), blood products transfusion (2.9 percent vs 0.8 percent; aRR, 2.60, 95 percent CI, 1.84–3.69), and SGA birth weight (8.5 percent vs 6.8 percent; aRR, 1.23, 95 percent CI, 1.01–1.50).

Those with resolved anaemia by late pregnancy also showed increased risks of blood products transfusion (1.6 percent vs 0.8 percent; aRR, 1.64, 95 percent CI, 1.01–2.67) and SGA birth weight (10 percent vs 6.8 percent; aRR, 1.38, 95 percent CI, 1.15–1.67) compared with those who had no anaemia in the first trimester.

These findings underscore the importance of treating anaemia in early pregnancy and before pregnancy.