Clotting conditions, which can ultimately affect the lungs are among the leading causes of maternal death worldwide. A Swedish cross-sectional study recently tied in-vitro fertilization to maternal increased risk for venous thromboembolism and pulmonary embolism.
As infertility affects more than 10% of couples worldwide, identifying in-vitro fertilization linked conditions has become a pressing matter. The two aforementioned conditions affect mothers in that they result in clots that can move to a lung artery and block oxygen flow (potentially dangerous for mothers and unborn children).
The 1990 to 2008 spanning study included 23,498 women who had their first child through in-vitro fertilization and 116,960 matched women who had their first child through natural pregnancy. All data analyzed came from the Swedish national patient register and the National Board of Health and Welfare.
Results showed increased incidence of venous thrombosis for women who underwent in-vitro fertilization (4.2/1,000) versus women who gave natural birth (2.5/1,000). Hazard ratio of 1.77, 95% CI 1.41 to 2.23. Risk was especially high during the first trimester for venous thrombosis. Pulmonary embolism showed similar results in that more cases were seen in women who went through in-vitro fertilization (8.1/10,000) versus those who had natural births (6.0/10,000). Hazard ratio of 1.42, 95% CI 0.86 to 2.36). Again, risk was seen as increased during the initial trimester.
The author of the source article may have put it best, “The risk of pulmonary embolism [and venous thromboembolism] is low in absolute terms but because the condition is a leading cause of maternal mortality and clinical suspicion is critical for diagnosis, an awareness of this risk is important.”
Peter Henriksson, Eli Westerlund, Håkan Wallén, Lena Brandt, Outi Hovatta, Anders Ekbom. Incidence of pulmonary and venous thromboembolism in pregnancies after in vitro fertilisation: cross sectional study. British Medical Journal, 2013.