Obstetrics
Pulmonary embolism and stroke in relation to pregnancy: How can high-risk women be identified?,☆☆

https://doi.org/10.1067/mob.2002.119177Get rights and content

Abstract

Objective: Risks of circulatory diseases are increased substantially during late pregnancy and around the time of delivery. This study was undertaken to determine whether preeclampsia, multiple pregnancy, or cesarean delivery account for the majority of pregnancy-related risks of pulmonary embolism and stroke (caused by hemorrhage, infarction, and intracranial venous thrombosis). Study Design: We analyzed a population-based cohort of 1,003,489 deliveries in Sweden. Relative risks of pulmonary embolism and stroke were modeled by use of Poisson regression. Results: Preeclampsia was associated with 3- to 12-fold increases in risks of pulmonary embolism and stroke during late pregnancy, at delivery, and in the puerperium, and similar increases in risks were also observed for multiple pregnancies and cesarean delivery. These strong associations could not explain the overall pregnancy-related risks of pulmonary embolism and stroke. Conclusion: Preeclampsia, multiple birth, and cesarean delivery are important risk factors for pulmonary embolism and stroke, but they do not account for the majority of the excess risks associated with pregnancy. (Am J Obstet Gynecol 2002;186:198-203.)

Section snippets

Patients and methods

We conducted the present population-based cohort study through cross-linkage of the nation-wide Swedish Inpatient and Birth Registers, held by the National Board of Health and Welfare. Individual record linkage between these registers was obtained by using the unique national registration number assigned to each Swedish resident. The coverage is 99% of the deliveries and inpatient care during the study period.15, 16

Results

Table I shows that pregnancy status, maternal age, parity, smoking, preeclampsia, multiple birth, diabetes, and cesarean delivery are all associated with risks of pulmonary embolism and stroke.

. Crude relative risk with 95% CI for pulmonary embolism and stroke among 654,957 women (1,003,489 deliveries) who gave birth in Sweden during 1987-1995

Empty CellPulmonary embolismStroke
No.of casesRRCINo. of casesRRCI
Period*
Reference1481.0Reference1961.0Referemce
Third trimester293.22.1-4.7262.11.4-3.2
Around delivery34

Comment

The results of the present study demonstrate that preeclampsia, multiple birth, and cesarean delivery are associated with markedly increased risks of pulmonary embolism and stroke related to pregnancy and that these risks also increase with maternal age and smoking. However, these factors cannot explain the pregnancy-related risks of pulmonary embolism and stroke.

The detailed and individual data available from registers, with almost complete nationwide coverage of deliveries and inpatient care,

References (21)

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Supported by grants from the Swedish Medical Research Council (No. 27X-12276).

☆☆

Reprint requests: Helena Salonen Ros, Department of Medical Epidemiology, Karolinska Institutet, PO Box 281, SE-171 77 Stockholm, Sweden. E-mail: [email protected].

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