A need for more research on how lifestyle interventions could help high-risk pregnant populations

By Dr. Priyom Bose, Ph.D.Reviewed by Danielle Ellis, B.Sc.Jan 5 2023

The prevalence of chronic hypertension (CH) and type 1 diabetes mellitus (DM) or type 2 diabetes mellitus (T2DM) has increased considerably in the pregnant population over the recent decades. Notably, the percentage of its occurrence has continued to rise due to increasing rates of obesity and advances in maternal age. Obesity is a key risk factor influencing CH or DM/T2DM.

Study: Evidence of lifestyle interventions in a pregnant population with chronic hypertension and/or pre-existing diabetes: A systematic review and narrative synthesis. Image Credit: Kzenon / Shutterstock

Background

Compared to the general population, women with chronic CH are at a higher risk of developing superimposed pre-eclampsia and experiencing adverse neonatal outcomes. Women with pre-existing diabetes are almost at a four times higher risk of fetal death and obstetric and neonatal complications compared to the general population. Women with CH and/or pre-existing diabetes are prone to develop cardiovascular disease (CVD). Therefore, examining these groups during pregnancy is imperative to alleviate short- and long-term risks.

Weight management is highly effective in managing CH and diabetes. Although weight loss is not recommended during pregnancy, avoiding excessive gestational weight gain (GWG) is essential as it enhances the possibility of adverse pregnancy outcomes. It has been observed that lifestyle interventions improve the quality of life of the non-pregnant hypertensive population. For instance, a significant decrease in systolic blood pressure was found after implementing healthy dietary intake.

Although it has been established that pregnant women must try to avoid having elevated blood pressure, the effect of lifestyle interventions on blood pressure in pregnant women with pre-existing diabetes or CH is not clear.

Typically, pregnancy is perceived as a 'teachable moment' where most women remain motivated to adopt practices that reduce risks associated with pregnancy outcomes. A meta-analysis including 12,526 women revealed that proper diet and physical activity reduced GWG; however, this study failed to provide conclusive evidence on whether these interventions improve maternal and fetal outcomes. In addition, few studies on the effect of weight changes on blood pressure levels in pregnant women are available.

Recently, scientists reviewed the effect of lifestyle interventions in pregnant women with CH and/or pre-existing DM and T2DM. The authors also focused on the evidence associated with the impact of lifestyle interventions on this group's blood pressure and gestational weight. This review is available in the journal Pregnancy Hypertension: An International Journal of Women's Cardiovascular Health. 

About the Study

In this study, data on randomized controlled trials (RCT) associated with pregnant women with CH and/or those with a pre-existing DM/T2DM was obtained from Embase, CINHAL, PsycINFO, Medline, and Web of Science.

Studies related to lifestyle interventions practiced during the antenatal period were included in this study. In addition, the diet pattern, gestational weight, and physical activities of pregnant women with CH and/or pre-existing DM and T2DM were analyzed. Importantly, wherever possible, fetal, maternal, and neonatal outcomes concerning the lifestyle interventions in the focus group were investigated.

Study Findings

A total of 1,464 articles were screened for eligibility to be included in the study, seven of which were standard RCTs and two cluster RCTs. These studies were conducted in Australia, the UK, Brazil, and nine European countries. The selected nine studies constituted a total of 7,438 pregnant women diagnosed with CH and/or who had pre-existing DM/T2DM.

Among the nine studies, eight were found to have a low risk of bias, and one had an unclear risk. The current review uncovered that most research focused on interventions to support lifestyle change during pregnancy. However, none of the studies evaluated its effect on pregnant women with CH. In one study that analyzed women with pre-existing diabetes, their cohort included a mixed population, i.e., pregnant and non-pregnant women with the condition. Hence, this lacked focused information on pregnant women alone.

Interestingly, it was observed that most of the trials exclude pregnant women with chronic conditions. However, some trials that include this group fail to perform sub-group analysis. Although data on gestational weight change was easily found, a similar frequency of data on the blood pressure changes of this group was not found.

Conclusions

The authors claim this study to be the first to systemically review the effect of lifestyle interventions in the pregnant population with CH or pre-existing diabetes. The authors have successfully identified the gap in the existing research, which researchers should consider in the future. Another strength of this review is its methodology which included double screening and data extraction based on the discussions on discrepancies to enhance reliability. 

Due to inadequate data on the eligibility criteria in many studies, the authors made several assumptions. For instance, many a time, authors were not clear if a particular pregnant woman with pre-existing diabetes also had CH.

The current study helped collect information and build a guide that could serve as a foundation for future research. However, this review indicated a lack of clarity and data on lifestyle interventions' impact on pregnant women with CH or pre-existing DM/T2DM.