Abstract Background The risk of venous thromboembolism (VTE) is tenfold higher in pregnant women compared to age-matched non-pregnant women.¹ Obesity (BMI30) further increases the risk of VTE.² However, few studies have investigated whether excessive gestational weight gain (eGWG) affects the risk of VTE. As more and more women start pregnancy overweight - at BMI25 and gain more weight than recommended, there is a need for more knowledge in this field. Purpose To assess the relationship between eGWG and the risk of VTE during pregnancy and postpartum. Method A nationwide registry study from 2014 until 2019, including primiparous women aged up to 50 years with singleton pregnancies. VTE events during pregnancy and up to 3 months postpartum were identified using the National Patient Register and the National Medical Birth Register. Gestational weight gain was calculated by subtracting the last registered weight (minimum after gestational week 22) from the weight registered before week 12 of gestation. GWG was assessed based on BMI group and recommendations from the American Institute of Medicine. Women could either gain below, within (reference category), or above the recommended weight according to BMI. Crude and adjusted odds ratios (OR/aOR) of VTE were calculated using logistic regression. Results This study included 324,921 women. In all, 515 cases of VTE were identified. While 30% of women with BMI25 had eGWG, 62% of women with BMI25 had eGWG. Women who had GWG below the recommendation of their BMI group had a higher risk of VTE compared to those with recommended weight gain (OR of 1.28 (95% CI 1.03-1.59, p=0.024). Women with GWG above recommendation did not have an increased risk (OR 0.85 (95% CI 0.68-1.07, p=0.176), independent of BMI group. In the group who had VTE, 7.6% also had preeclampsia, compared to 4.3% in those who did not suffer from VTE (p=0.001) demonstrating a 38% higher incidence of preeclampsia in the VTE-group. Conclusion Of pregnant women with BMI25, 62% had a GWG above recommendation. Women with GWG below recommendation had a higher risk of VTE during pregnancy or postpartum, while women above recommendation did not, compared to those with GWG within recommendation.
Hassbring et al. (Sat,) studied this question.