Blood coagulation profile in pregnant women with severe anaemia linked to postpartum bleeding

Altered measures of the coagulation parameters, specifically high international normalised ratio (INR) and low haemoglobin (Hb), in the third trimester of pregnancy among women with severe anaemia appear to contribute to an increased risk of postpartum haemorrhage (PPH), a study has found.

The study included 1,342 women in their third trimester of pregnancy. They underwent measurements of Hb and coagulation parameters, including fibrinogen, D-dimer, D-dimer/fibrinogen ratio, platelets, and INR. All women were examined within 2 hours after childbirth to measure blood loss, with PPH defined based on blood loss and clinical assessment.

Of the women, 5.3 percent had severe anaemia (Hb <7 g/dL) and 34.7 percent had moderate anaemia (Hb 7–9.9 g/dL); more than half (58.9 percent) of the women had no or mild anaemia. The mean haematocrit was 21 percent, 30 percent, and 37 percent, respectively. Most of the women had iron-deficiency anaemia.

Compared with women with no or mild anaemia, those with severe anaemia had 27-percent higher D-dimer, 117-mg/dL lower mean fibrinogen, 69-percent higher D-dimer/fibrinogen ratio, and 12-percent higher INR. Furthermore, mean platelets were 37.8×109/L lower among women with severe vs moderate anaemia.

A similar pattern of associations, although with smaller effect sizes, was seen for women with moderate anaemia relative to those with no/mild anaemia.

Multivariable logistic regression models showed that the odds of having a PPH at childbirth rose by 22 percent for every 1-g/dL drop in Hb (adjusted odds ratio [aOR], 0.78, 95 percent confidence interval [CI], 0.63–0.98), with the odds nearly twofold higher in women with moderate anaemia and more than fivefold higher in women with severe anaemia compared with women vs mild/no anaemia.

PPH at childbirth was also associated with an INR >1.1 during the third trimester of pregnancy.