(RxWiki News) When a woman is pregnant, the hormones her body makes can increase her risk of experiencing a blood clot. Other factors might increase this risk further.
A recent study found that women who had been hospitalized while pregnant were at a higher risk for blood clots than non-hospitalized pregnant women.
This finding referred to women who had been hospitalized for reasons not related to giving birth or having a blood clot.
The risk varied according to a woman's age and which trimester of pregnancy she was in.
The risk also depended on how long the women spent in the hospital. The longer she was in the hospital, the higher her risk was.
"Attend all prenatal appointments."
The study, led by Alyshah Abdul Sultan, a doctoral student in the Division of Epidemiology and Public Health at the University of Nottingham in the United Kingdom, looked at ways of preventing blood clots in pregnant women.
For this study, researchers examined the cases of 206,785 women, aged 15 to 44, who had at least one pregnancy between 1997 and 2010 in England.
The researchers compared how commonly women experienced blood clots while pregnant if they were or were not hospitalized during their pregnancies.
They were specifically looking at women who had been hospitalized for at least one day for reasons unrelated to blood clots or giving birth.
The researchers found that out of 100,000 pregnant women in a single year, a total of 1,752 women who had been admitted to the hospital would experience a blood clot while at the hospital.
Pregnant women who had been admitted to the hospital experienced blood clots about 17.5 times more frequently than pregnant women not in the hospital.
Typically, out of 100,000 pregnant women in a single year, about 112 of them would be expected to experience a blood clot while pregnant. About 32 out of 100,000 women would have a blood clot in a single year while not pregnant.
The risk of a blood clot in pregnant women who had spent time in the hospital also appeared to be higher even after they left the hospital.
In this study, 676 of 100,000 pregnant women who had been hospitalized in a single year experienced a blood clot within four weeks of being discharged from the hospital.
Pregnant women who had been hospitalized appeared to be at even higher risk for a blood clot if they were in their third trimester or if they were at least 35 years old.
Among pregnant women aged 35 and older, 1,756 out of 100,000 in a single year would experience a blood clot during pregnancy if they had been hospitalized during the pregnancy.
Women who spent at least three days in the hospital experienced blood clots at a rate 12 times higher than pregnant women who had never been admitted to the hospital while pregnant.
Among those spending fewer than three days in the hospital while pregnant, the likelihood of having a blood clot was four times higher than among non-hospitalized pregnant women.
The researchers therefore determined that pregnant women admitted to the hospital for any reason are at higher risk for blood clots and should be carefully monitored.
The study was published November 6 in the journal BMJ. The research was funded by the Aga Khan Foundation and the University of Nottingham.
One author has received speaking fees from Leo Pharma and Sanofi Aventis, both of whom manufacture two blood-thinning medications that women at risk of blood clots might use. This author has also been paid by Leo Pharma to develop an educational kit related to treating blood clots in pregnancy.
