Pre-eclampsia and gestational diabetes mellitus are associated with an increased risk of cardiovascular diseaseDear Dr Papageorghiou,We read with great interest the article published in BJOG by Hildén et al.1, in which the authors aimed to investigate if the pre-eclampsia association with cardiovascular disease (CVD) was independent of gestational diabetes mellitus (GDM). They indicated that pre-eclampsia and GDM were independent risk factors for CVD, and after stratifying by maternal body mass index (BMI), the adjusted association of pre-eclampsia with CVD did not differ notably between BMI groups. They concluded that pre-eclampsia and GDM were independent risk factors for later CVD and having both during pregnancy was a major risk factor for later CVD. Furthermore, they indicated that the association between pre-eclampsia and CVD was not modified by BMI.We support the information provided by Hildén et al.1, and hypertension is a mediator of CVD rather than a component of the diagnostic bundle. It has been shown that pre-eclampsia and GDM can affect blood vessels, but it is not clear aetiology2. Previous studies indicated that women with GDM have an increased risk of developing preeclampsia, which in turn increases the risk of developing advanced CVD3,4. However, in these studies, there were many potential confounding factors due to the lack of adjustment for BMI. The current research just filled in this disadvantage. We thank Hildén et al.1 for their comprehensive contribution.We believe that the biggest advantage of this study is that it is a nationwide study, and the data collected prospectively has high credibility. The main disadvantage is that women with diabetes before pregnancy are excluded, which may have a great impact on the research results, leading to bias. This nested case-control study included 2639 cases and 13310 controls with complete data. So large number of study population will provide valuable guidance for clinicians to improve their understanding of pre-eclampsia and GDM related CVD, despite some limitations of this study. In addition, we are also looking forward to Hildén et al.1 developing effective CVD prevention plans for high-risk women to improve their long-term health. Therefore, we believe the research by Muraca et al.1 will greatly promote further researches on the pre-eclampsia and GDM related CVD.