It is a well-accepted fact in the medical community that the longer a patient stays in the hospital, the more likely a blood clot will develop. A blood clot, also called venous thromboembolism (VTE), can be life-threatening.

Venous thromboembolism is one of the most common causes of death to pregnant women and mothers in the developed countries of the world. It develops in 1 or 2 pregnancies per every 1,000 pregnancies.

In the United Kingdom (UK) alone, VTE is the cause of more than 25,000 deaths in the general population each year.

Women who are hospitalized during pregnancy for reasons other than the birth of the child they carry also experience clots. Until recently, however, no medical studies have been conducted that examine the increased risk, if any, of venous thromboembolism during pregnancy alone.

Researchers affiliated with two medical facilities in the UK were curious enough to conduct a study weighing the risk of blood clots in pregnant women during non-delivery hospitalizations. Their findings were recently published in BMJ, the medical journal published by the British Medical Association.

The research team, affiliated with the Guy’s & St Thomas’ Foundation Trust in London and the University of Nottingham (England), reviewed primary- and secondary-care medical records of 206,785 pregnant women hospitalized for non-delivery reasons. The women’s ages ranged from 15 to 44, none of them had any previous history of VTE, and each was pregnant one or more times between 1997 and 2010. Any pre-existing medical conditions or medical conditions related to maternity were taken into consideration.

The research team identified a substantially increased risk of serious blood clotting in these women, a risk that lingered as long as 28 days after the patient was discharged from the hospital. Findings include:

  • VTE development in 16.6 hospitalizations per 1,000 person-years of hospitalization, or a 17.5-fold increased risk of clot development in these women over the general population.
  • VTE development in 5.8 cases per 1,000 person-years in the first 28 days following discharge.
  • VTE most likely to occur during the third trimester.
  • VTE more likely to occur in women 35 years and older.
  • When the hospital stay was less than three days, the risk of VTE was 4.6 cases per 1,000 person-years.
  • With three or more days of hospitalization, the risk of VTE was 14.1 per 1,000 person-years.

According to the study’s authors, their findings suggest “careful consideration” of the potential need for anti-clotting drugs when women are hospitalized for non-delivery reasons during pregnancy.

Source: “Study finds high clot risk for women admitted to hospital during pregnancy.” BMJ. Nov. 7, 2013. Web. Nov. 19, 2013.