Gestational diabetes mellitus (GDM) affects 1–45% of pregnancies depending on the population and diagnostic criteria selected (1). A meta-analysis with 12 randomized controlled trials (RCTs) showed that GDM management improves pregnancy outcomes (2). GDM management involves counseling, dietary modification, physical activity, glucose monitoring, and, where glycemic thresholds are exceeded, supplemental pharmacological therapies. Implementation varies, with possible consequences for the pregnancy outcomes. For example, the Australian Carbohydrate Intolerance Study in Pregnant Women (ACHOIS) and Maternal–Fetal Medicine Units Network (MFMUN) RCTs, the two largest GDM treatment trials, differed in their insulin use (20% vs. 8%, respectively) and outcomes (3, 4). Within the MFNUM RCT, the median glucose achieved was 10–12 mg/dL (0.6 mmol/L) higher in the insulin-treated than the non–insulin-treated group, particularly after dinner, when 50% of the self–blood glucose monitoring results were over the target glucose (median glucose was 120 mg/dL [6.7 mmol/L]). The more self–blood glucose monitoring results occur above target, the greater the chance of an adverse pregnancy outcome. In one study, adverse outcomes occurred in 25% vs. 60% of births among those with none vs.. 30% above-target results, respectively (5). There are multiple barriers to GDM management for women with GDM (6). Besides a range of socioeconomic, service, and access barriers, women may experience misunderstanding or confusion over the advice provided, as well as a range of emotional and psychological challenges. Meanwhile, the increasing number of women with GDM (7) has created greater pressure on health care providers to streamline their services with different models of care, often sharing management with non–diabetes service staff (8).

New technologies such as telemedicine, SMS messaging, websites, e-mail, and smartphone applications (“apps”) have been introduced in a range of settings to help address access and educational and behavioral support needs (9), and GDM management is no exception. Telemedicine technologies can be effective in GDM management (10). However, smartphone-based apps alone have not been clearly shown to improve glycemia or pregnancy outcomes in women with GDM. Studies have tested the clinical use (11–16) and cost-effectiveness (12) of GDM apps. All (12, 13, 15) have been underpowered (including 120–238 women) to detect improvement in pregnancy outcomes. Better compliance with blood glucose monitoring (13, 14), significantly lower blood glucose (11, 13, 14), and a lower rate of insulin need (13) have been shown in some studies. However, others (12, 15)