Hypertensive disorders of pregnancy
An opportunity to begin lifelong control of cardiometabolic risk factors
In this issue of The BMJ the question of the long term follow-up for women with hypertensive disorders of pregnancy is examined in two substantial datasets: a nationwide cohort in the Danish study by Behrens and colleagues (doi:10.1136/bmj.j3078)1 and data from the Nurses’ Health Study II in the trial by Timpka and colleagues (doi:10.1136/bmj.j3024).2 Taken together these two studies tease out some of the complexities underlying the development and long term impact of hypertensive disorders of pregnancy and the relation between these disorders and general cardiometabolic risk factors. The findings emphasise the need to recognise as a lifelong risk factor any episode of gestational hypertension, pre-eclampsia, eclampsia, or HELLP syndrome.
Both studies confirm other recent cohort studies3 suggesting that risk factors for hypertensive disorders of pregnancy are present before conception. Participants in the Nurses’ Health Study II who subsequently developed a hypertensive disorder of pregnancy had a higher body mass index (BMI) at baseline than other participants. They were more likely to have a history of gestational diabetes mellitus and more likely to have parents with a history of chronic hypertension. Importantly, these women did not appear to be leading less healthy lifestyles than others at the outset of the study, with similar levels of physical activity, dietary scores, and sodium and potassium intake at baseline. In the Danish study, rates of prepregnancy type 1 and type 2 diabetes, overweight, and obesity were higher among women who developed hypertensive disorders of pregnancy.
One of the key questions around long term follow-up is whether pregnancy merely unmasks an already existing cardiometabolic disorder, or whether a hypertensive disorder of pregnancy is directly responsible for adverse long term outcomes.
The Nurses’ Health Study II shows the pivotal role of BMI in the development of chronic hypertension after an affected pregnancy. BMI and hypertensive disorders of pregnancy interact, combining to increase the risk of chronic hypertension more than might be expected from the risk associated with either one alone. We need a more detailed understanding of the mechanisms underpinning this interaction, including the relative contributions of genetics, appetite regulation, and autonomic regulation.45
The Danish study explores the risk of chronic hypertension among women with consecutive pregnancies affected or unaffected by a hypertensive disorder. The authors find a differential effect of pregnancy order—women with two consecutive affected pregnancies were at highest risk of chronic hypertension. Among women with discordant pregnancies, those with an unaffected followed by an affected pregnancy were at greater risk of chronic hypertension than those with the converse. This pattern would not emerge if a hypertensive disorder of pregnancy contributed directly to chronic hypertension and cardiometabolic risk later. But it does support the idea that pregnancy unmasks a pre-existing cardiometabolic disturbance that continues to influence later health outcomes.
Professional bodies increasingly recognise that a hypertensive disorder of pregnancy has long term implications for affected women,67 but clinical follow-up by health professionals remains inadequate.89 The Danish study shows that gestational hypertension should not be regarded as any less risky than pre-eclampsia for long term outcomes. Findings from both studies reinforce the message that women who have had a pregnancy complicated by any hypertensive disorder should remain under close surveillance for life.
Debates about the long term management of women after a hypertensive disorder of pregnancy overlap to some extent with debates about women with a history of gestational diabetes. Both conditions have long term health implications for mother and infant. It is already known that in women with a pregnancy complicated by gestational diabetes, intensive lifestyle interventions or metformin reduce the development of type 2 diabetes.10 Both linked studies identify an urgent need for well designed, long term trials of clinical interventions for women with a hypertensive disorder of pregnancy. Timpka and colleagues helpfully point to “whole of family” interventions that might address this multigenerational issue.
Closer collaboration would also be helpful between groups with an interest in gestational diabetes, and those with an interest in hypertensive disorders of pregnancy. Both conditions represent cardiometabolic risk unmasked by pregnancy. Both are underpinned by overweight, obesity, and insulin resistance. Both require long term modification of cardiometabolic risk factors and have an evidence base that leaves unanswered questions about the most effective interventions and how best to implement them.
For women and their doctors, however, it is much simpler. They need longstanding therapeutic relationships that foster trust and enable regular checks of blood pressure, blood glucose concentrations, lipid profiles, weight, stress, sleep, and smoking status. Within these relationships, clinicians are perfectly placed to help empower women to take care of themselves.
- HLB is supported by an early career fellowship from the National Health and Medical Research Council.
- Competing interests: We have read and understood the BMJ policy on declaration of interests and declare the following: none.
- Provenance and peer review: Commissioned; not peer reviewed.
- Behrens I, Basit S, Melbye M, et al. Risk of post-pregnancy hypertension in women with a history of hypertensive disorders of pregnancy: nationwide cohort study. BMJ2017;358:j3078.
Timpka S, Stuart JJ, Tanz LJ, Rimm EB, Franks PW, Rich-Edwards JW. Lifestyle in progression from hypertensive disorders of pregnancy to chronic hypertension in Nurses’ Health Study II: observational cohort study. BMJ2017;358:j3024.
Egeland GM, Klungsøyr K, Øyen N, Tell GS, Næss Ø, Skjærven R. Preconception Cardiovascular Risk Factor Differences Between Gestational Hypertension and Preeclampsia: Cohort Norway Study. Hypertension2016;67:1173-80. doi:10.1161/HYPERTENSIONAHA.116.07099 pmid:27113053.
Spradley FT. Metabolic abnormalities and obesity’s impact on the risk for developing preeclampsia. Am J Physiol Regul Integr Comp Physiol2017;312:R5-12. doi:10.1152/ajpregu.00440.2016 pmid:27903516.
Callaway LK, O’Callaghan M, McIntyre HD. Obesity and the hypertensive disorders of pregnancy. Hypertens Pregnancy2009;28:473-93. doi:10.3109/10641950802629626 pmid:19843008.
Heida KY, Bots ML, de Groot CJ, et al. Cardiovascular risk management after reproductive and pregnancy-related disorders: A Dutch multidisciplinary evidence-based guideline. Eur J Prev Cardiol2016;23:1863-79. doi:10.1177/2047487316659573 pmid:27432836.
Mosca L, Benjamin EJ, Berra K, et al. American Heart Association. Effectiveness-based guidelines for the prevention of cardiovascular disease in women--2011 update: a guideline from the American Heart Association. J Am Coll Cardiol2011;57:1404-23. doi:10.1016/j.jacc.2011.02.005 pmid:21388771.
Callaway LK, David McIntyre H, Williams GM, Najman JM, Lawlor DA, Mamun A. Diagnosis and treatment of hypertension 21 years after a hypertensive disorder of pregnancy. Aust N Z J Obstet Gynaecol2011;51:437-40. doi:10.1111/j.1479-828X.2011.01345.x pmid:21883134.
Young B, Hacker MR, Rana S. Physicians’ knowledge of future vascular disease in women with preeclampsia. Hypertens Pregnancy2012;31:50-8. doi:10.3109/10641955.2010.544955 pmid:21332326.
Aroda VR, Christophi CA, Edelstein SL, et al. Diabetes Prevention Program Research Group. The effect of lifestyle intervention and metformin on preventing or delaying diabetes among women with and without gestational diabetes: the Diabetes Prevention Program outcomes study 10-year follow-up. J Clin Endocrinol Metab2015;100:1646-53. doi:10.1210/jc.2014-3761 pmid:25706240.
ISSN (electronic): 1756-1833
Publisher: British Medical Journal Publishing Group
Publication date (electronic): 13 July 2017
Electronic Location Identifier: j3245
Copyright statement: Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions
Copyright: 2017, BMJ
Related article (commentary article): Research, doi: 10.1136/bmj.j3078 , doi: 10.1136/bmj.j3024
Obstetric Medicine, Royal Brisbane and Women’s Hospital, Brisbane, Australia
UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Australia
Correspondence to: L K Callaway [email protected]
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