Interventions designed to reduce excessive gestational weight gain can reduce the incidence of gestational diabetes mellitus: A systematic review and meta-analysis of randomised controlled trials
Introduction
The prevalence of gestational diabetes mellitus (GDM) is increasing globally [1] and currently affects between 9 and 16% of all pregnancies [2]. Gestational diabetes mellitus is a failure to maintain glucose homeostasis with resultant metabolic and inflammatory stress to mother and fetus [3]. Immediate implications of GDM for obstetric care include macrosomia, the need for emergency caesarean section and risk of prematurity [4]. In the longer term, epigenetic programming of the fetus to be more susceptible to metabolic diseases may have a major impact on the health system [5]. In women diagnosed GDM, glucose tolerance often returns to normal after birth, but their risk of developing type 2 diabetes mellitus later in life is increased 7–12-fold [6].
During pregnancy, excessive gestational weight gain (GWG) can independently increase the risk of developing GDM by 53% [7]. Compared to women with a healthy BMI, women who are overweight or obese at conception are two and four times more likely to develop GDM, respectively [8]. Furthermore, genetic heritage influences the risk of GDM. Women with backgrounds from Eastern Asia, India, Bangladesh, Pakistan, and Mexico are two to seven times more likely to develop GDM compared to Caucasians, even after adjusting for maternal age, education and pre-pregnancy weight [9].
The US Institute of Medicine, (IOM) has published recommendations for GWG based on pre-pregnancy BMI [10] but no global consensus exists [11]. Strategies that can reduce excessive GWG and possibly the risk of GDM risk have particular relevance in developing nations such as China which have increasing rates of overweight and obese contributing to the double burden of disease [12]. Migratory patterns, combined with the ethnic and cultural diversity of populations, mean that clinicians will see women with varying degrees of risk for developing GDM and the ‘one size fits all’ model to screening women for glucose intolerance may need refining. Understanding more about what interventions and advice are successful, and in what populations, is very important in clinical decision making. Previous reviews have largely been conducted in literature published in English, with studies published in Spanish, Portuguese or Chinese databases being excluded. This reduces the ethnic diversity of the populations examined and impacts on the generalisability of results. The population of China accounts for 20% of the world’s population, this presents a substantial gap in the literature. While maternal weight gain may influence subsequent maternal insulin resistance, surprisingly it is unknown if interventions designed to reduce excessive GWG can also reduce the incidence of GDM [13]. Given these two inter-related issues, the aim of this review was to (i) comprehensively evaluate the global impact of interventions designed to prevent excessive GWG on the incidence of GDM, and (ii) to examine whether the effects differ by maternal BMI or ethnicity.
Section snippets
Protocol and registration
This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews (PRISMA) statement. The systematic review was registered with PROSPERO (CRD: 42016035907) and this paper reports specifically on the pre-specified secondary outcomes.
Data sources and searches
The search strategy was conducted using two parallel methods. Two native English speakers (RW and CB) independently conducted the search in the following databases: Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, Scopus, and
Results
The flow diagram of included studies is outlined in Fig. 1. Initially, 20,517 manuscripts were identified from the search. A total of 45 studies (n = 15,293 participants) satisfied the inclusion criteria and were included in the systematic review. Included studies were published between 2002 and 2016. The studies included women between 9 and 28 weeks’ gestation, with Singleton, non-complicated pregnancies. Interventions lasted an average of 25 weeks (range 9–34 weeks). Twenty-six studies
Discussion
This review found that single behavior interventions, such as diet or physical activity, designed to reduce excessive GWG were more effective than standard antenatal care in reducing the incidence of GDM. However, interventions were less effective in women with a high pre-pregnancy BMI. Interventions designed to reduce excessive GWG also reduced the incidence of GDM in Asia and Southern Europe. However, in regions such as America, Australia and other parts of Europe there was no reduction in
Conclusion
Worldwide interventions designed to reduce excessive GWG that target single behaviors (i.e. a change in diet or change in physical activity NOT both combined) were found to reduce the incidence of GDM. While this is true for women across a range of BMI’s, interventions were less effective in women with a high pre-pregnancy BMI. When analyses were stratified by region, Asia and Southern Europe were the only regions where interventions reported a significant reduction in the risk of developing
Funding
No funding was received for the preparation of this systematic review.
Conflict of interest
The authors have no conflicts of interests to declare.
Registration
PROSPERO (CRD: 42016035907).
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