Non-Delivery Hospital Stay May Raise Clot Risk During Pregnancy

Pregnant women are at an increased risk for blood clots if they're admitted to the hospital for reasons other than delivery, a new study finds.

Researchers looked at data from more than 206,000 women, aged 15 to 44, in the United Kingdom who had one or more pregnancies between 1997 and 2010. None of the women in the study had a history of blood clots.

The analysis showed that hospitalization during pregnancy was associated with a nearly 18-fold increased risk of developing a blood clot. The risk remained high for 28 days after discharge, particularly among women who were hospitalized for three or more days.

The investigators also found that blood clots among pregnant women in the hospital were more likely to occur in late pregnancy and in women 35 and older, according to the study, which was published online Nov. 7 in the journal BMJ.

Blood clots occur in one to two of every 1,000 pregnancies, and they are one of the leading causes of death among pregnant women in developed countries, study author Alyshah Abdul Sultan, of the division of epidemiology and public health at the University of Nottingham, and colleagues said in a journal news release.

The study findings indicate that "careful consideration" is needed when assessing which pregnant women should receive anti-clotting drugs while in the hospital, said the researchers, from the University of Nottingham and Guy's & St. Thomas' Foundation Trust in London.

In the general population, hospitalization greatly increases a person's risk of blood clots, but it hadn't been clear if the same level of risk occurred in pregnant women. This is believed to be the first study to look at the issue, the researchers said.

More information

The American Society of Hematology has more about pregnancy and blood clots.