By PPH Foundation

For decades, postpartum haemorrhage, PPH, has been understood largely as an obstetric emergency associated with complications such as uterine atony, retained placenta, prolonged labour, multiple pregnancy and clotting disorders. However, emerging scientific evidence suggests that another factor may influence a woman's risk of severe bleeding after childbirth, her genes.

Although most women who experience postpartum haemorrhage do not have a family history of the condition, researchers are increasingly finding that inherited genetic factors may partly explain why some women are more susceptible than others. These discoveries are opening new opportunities for identifying women at higher risk during pregnancy and strengthening preparedness before delivery.

One of the strongest pieces of evidence comes from a nationwide Norwegian study involving approximately one million parent-offspring combinations. Researchers found that women whose close relatives had experienced postpartum haemorrhage were significantly more likely to experience the condition themselves. The pattern of recurrence closely mirrored the proportion of shared genes, with the strongest association observed among full sisters, followed by maternal half-sisters, paternal half-sisters and partners of full brothers. Importantly, the recurrence was stronger through the maternal lineage, suggesting that hereditary factors play a meaningful role in postpartum haemorrhage susceptibility (Linde et al., 2021).

These findings were reinforced by a large prospective cohort study conducted in France involving 16,382 women over a three-and-a-half-year period. The study demonstrated that a family history of postpartum haemorrhage was associated with an increased risk of postpartum haemorrhage following vaginal delivery, providing further evidence that hereditary factors may contribute to what researchers describe as a haemorrhagic phenotype (Anouilh et al., 2023).

Building on these observations, scientists made another important breakthrough in 2024 by identifying genetic regions that may be associated with postpartum haemorrhage. While research is still in its early stages, the discovery provides the first molecular evidence that specific genes may influence susceptibility to severe bleeding after childbirth, paving the way for future research into personalized risk prediction and prevention strategies (Westergaard et al., 2024).

According to Professor Moses Obimbo, Project Lead of the End Postpartum Haemorrhage Initiative, these findings reinforce the importance of taking a thorough family history during antenatal care while recognising that genetics is only one part of the overall risk profile.

"Most women who develop postpartum haemorrhage have no known hereditary risk, and genetics should never be viewed as the sole cause of postpartum haemorrhage. However, the growing evidence that family history may increase susceptibility reminds us that comprehensive antenatal assessment is essential. Asking about previous postpartum haemorrhage among close relatives, alongside other clinical risk factors, can help healthcare providers anticipate complications and prepare appropriately."

He explains that preparedness remains the cornerstone of preventing maternal deaths.

"When healthcare providers recognise women who may be at increased risk, they can ensure skilled birth attendance, availability of uterotonics, tranexamic acid and blood products where necessary, while maintaining close observation during and after delivery. Early recognition and timely intervention continue to save lives."

Despite these exciting advances in genetic research, experts emphasise that heredity alone does not determine whether postpartum haemorrhage will occur. Many women with a family history deliver safely without complications, while others with no identifiable hereditary risk may still develop severe bleeding. Clinical factors, quality antenatal care, skilled birth attendance, active management of the third stage of labour, prompt recognition of excessive bleeding and rapid access to emergency obstetric care remain the most effective interventions for preventing maternal deaths from postpartum haemorrhage (World Health Organization, 2023).

As scientists continue to uncover the genetic mechanisms underlying postpartum haemorrhage, family history may become an increasingly valuable component of routine maternal risk assessment. Combined with evidence-based clinical care, these advances offer hope for more personalized approaches to identifying women at risk and ensuring every mother receives the right care at the right time.

References

Anouilh, T., et al. Family history as a risk factor for postpartum haemorrhage after vaginal delivery: A prospective cohort study. American Journal of Obstetrics and Gynecology MFM. 2023;5(9):101062.

Linde, L. B., et al. Family history and recurrence of postpartum haemorrhage: Evidence from the Norwegian Medical Birth Registry. Acta Obstetricia et Gynecologica Scandinavica. 2021;100(12):2278–2284.

Westergaard, D., et al. Genetic loci associated with postpartum haemorrhage. Nature Genetics. 2024;56(8):1597–1603.

World Health Organization. WHO recommendations for the prevention and treatment of postpartum haemorrhage. Geneva: World Health Organization; 2023.

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