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Obese mothers suffer from post-natal haemorrhaging more often

Obese women frequently experience haemorrhaging after childbirth due to their uterus failing to contract properly. This condition applies, in particular, to chronic obese women with a Body Mass Index (BMI) that exceeds 40, who are twice as likely to suffer from this condition than mothers of normal weight.

Both obesity among pregnant women and the proportion of bleeding associated with childbirth have increased in recent years. Now Marie Blomberg , chief obstetric physician and associate professor of obstetrics and gynaecology at Linköping University, has analysed data retrieved from more than one million births at Swedish women's clinics during the period: 1997-2008. Using this data, Blomberg examined cases where the mother lost over a litre of blood.

The results were published in the September issue of the journal Obstetrics & Gynecology and claim that obesity can cause haemorrhaging because the uterus does not contract immediately following the expulsion of the placenta. Blood loss of this magnitude requires medical intervention and possibly a blood transfusion.

Marie Blomberg has compared the outcome for mothers of normal weight with three groups of obese mothers.

Mothers with a BMI over 40 => risk increased by 114 %
Mothers with BMI 35-40 => risk increased by 47 %
Mothers with BMI 30-35 => risk increased by 14 %

The results are adjusted in consideration of other underlying factors for example; the risk of haemorrhaging was higher for older women and first-time mothers.

“There are two causes for post-natal haemorrhaging. One is that the uterus does not contract, the other being that the placenta remains in the uterus. This study shows that obesity increases the risk in the first case but not in the second case,” says Marie Blomberg.

Women who suffer from these haemorrhages can be treated with uterotonics, an agent that is used to induce contraction of the uterine muscles.

Text: Åke Hjelm 

  • Abstract from Article: Blomberg, M. Maternal obesity and risk of postpartum hemorrhage. Obstet Gynecol 2011; vol 118 p. 561-568.
  • View abstract.


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Last updated: 2012-12-10