Thrombotic risk during pregnancy: a population study.
OBJECTIVE
To determine the incidence of pregnancy-related venous thromboembolic events and the relationship to selected risk factors such as maternal age, parity, smoking, preeclampsia, or cesarean delivery.


METHODS
All Swedish women reported as having pregnancy-related venous thromboembolic events during 1990-1993 (608 of 479,422 deliveries) were compared with all thrombosis-free Swedish pregnant women during 1993 (114,940).


RESULTS
The incidence of pregnancy-related venous thromboembolic events was 13 per 10,000 deliveries. Cesarean delivery was associated with a fivefold increased risk of venous thromboembolic events. Advanced age was not a significant risk factor itself, but was associated with an age-related increase in frequency of cesareans. Women with preeclampsia were at a threefold higher risk postpartum, but at no increased risk before delivery. There was a tobacco consumption-dependent increase in the risk of thrombosis among smokers.


CONCLUSIONS
The incidence of pregnancy-related thrombosis was 13 per 10,000 and provided new insights to important risk factors such as age, cesarean delivery, smoking, and preeclampsia.
Lindqvist
P
P
Department of Obstetrics and Gynecology, and Coagulation Research, University of Lund, University Hospital, Sweden. pelle.lindqvist@obst.mas.lu.se
Dahlbäck
B
B
Marŝál
K
K
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D015994:Incidence; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000453:epidemiology*; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D013927:Thrombosis / Q000453:epidemiology*