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Medication for inherited blood clotting not effective at reducing miscarriages

Published: 01 June 2023

A medication prescribed for inherited blood clotting doesn't increase the chance of successful pregnancy in women with a history of recurrent miscarriage, finds an NIHR-funded study.

The anticoagulant drug treatment known as heparin has proven effective for pregnant women who have acquired blood clotting disorders. But until now it has not been clear whether it is effective for pregnant women with an inherited blood clotting condition called thrombophilia. 

Changing the way these women are treated could help save the NHS around £20m per year. It will also stop the need for them to receive daily injections of heparin which can cause bruising as a result.

The ALIFE2 Trial published in The Lancet on Thursday 1 June 2023. It showed a daily injection of heparin does not improve the chance of live birth for women with inherited thrombophilia who have had 2 or more miscarriages.

The trial was led by Professor Siobhan Quenby, Deputy Director of the Tommy’s National Centre for Miscarriage Research and Professor of Obstetrics at the University of Warwick. 

Professor Quenby said: "Many women with recurrent miscarriage around the world are tested for inherited thrombophilia and are treated with heparin daily. Research now shows that this screening is not needed, the treatment isn’t effective, and it is giving false hope to many by continuing to offer it as a potential preventive treatment."

The trial recruited 326 women with inherited thrombophilia and recurrent miscarriage. They were recruited from 40 hospitals in the UK, Netherlands, USA, Belgium and Slovenia. 164 women received heparin across the course of their pregnancy. This started after a positive pregnancy test and ended at the start of labour. 162 were not offered the medication.

All women received standard obstetrician-led care and were encouraged to take folic acid.

The rate of live births for each group was roughly the same. The risk of other pregnancy complications was about the same for both groups. This included miscarriage, babies with low birth weight, placental abruption, and premature birth or pre-eclampsia.

28% of women who participated in the trial lost their pregnancies. These unexplained losses will be the focus of further study for the researchers. They will continue to search for answers and treatment to prevent early pregnancy loss.

The treatment is costly for health services. Researchers say that the NHS could save around £20m per year if it:

  • stopped screening for inherited thrombophilia during pregnancy
  • ended the use of heparin as a treatment for inherited thrombophilia in pregnancy

This could allow funding for other services or treatments.

Read more about the study in The Lancet.

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