Gestational diabetes in women living with HIV in the UK and Ireland: insights from population-based surveillance data

The risk of gestational diabetes (GD) is increasing proportionally to type 2 diabetes in the general population and now affects an estimated 16% of pregnancies globally.1 Pregnancy is a physiological state of reduced insulin sensitivity2 and GD is thought to result from complex mechanisms involving beta-cell dysfunction influenced by genetic, epigenetic and environmental factors.3 Pregnant women in the UK considered to be “at risk” of developing GD are selectively screened at 24–28 weeks’ gestation based on body mass index (BMI) >30 kg/m2, previous macrosomic baby (>4.5 kg), family history of diabetes and belonging to a minority ethnic group with a high prevalence of diabetes.4 In 2015, clinical guidelines recommended a fasting plasma glucose ≥5.6 mmol/l or 2-hour glucose on the oral glucose tolerance test ≥7.8 mmol/l for GD diagnosis, which differs from international criteria (≥5.1 and ≥8.5 mmol/l) and was lowered from ≥7.0 mmol/l for fasting plasma glucose in 2008 based on findings from the HAPO study.5 While the universal risk factors for GD are reasonably well understood forming the basis of screening criteria, questions remain regarding the risk environment for women living with HIV (WLWH).

In the UK, there are approximately 800 pregnancies in WLWH each year, with 82% resulting in a delivery.6 The vertical transmission rate has decreased by 90%, from 2.1% in 2000–2001 to 0.22% in 2017–2018.7 Guidelines for HIV management, including in pregnancy, have evolved over time alongside the development of new antiretroviral drugs and classes, influencing both the timing of treatment initiation and drugs used in pregnancy.8 Since 2015 and the onset of the universal treatment era, women have increasingly been on treatment prior to conception;9 for example, in the UK, 81% of pregnancies were conceived on antiretroviral therapy (ART) in 2018.10 Furthermore, there have been changes in the characteristics of pregnant WLWH, including increasing maternal age, a growing number with vertically acquired HIV and a decreasing proportion born in sub-Saharan Africa.11, 12 The implications of lifelong treatment for nonpregnant populations may include increased risk of diabetes3, 14 and cardiovascular disease,15, 16 but findings on the effect of treatment in pregnancy, particularly protease inhibitors (PIs), on GD risk have been inconsistent.17-20 Using population-based data from the UK and Ireland from 2010 to 2020, our aim was to describe the prevalence of GD in WLWH, assess associated maternal risk factors and examine specific birth outcomes of pregnancies affected by GD.