Introduction
Depression and anxiety are the most common mental health conditions during pregnancy, with approximately 12% and 13% of women experiencing them, respectively.1 Antenatal depression and anxiety are associated with increased risk of post-partum depression, and poor cognitive and emotional development in the child.2South Asian (Indian, Pakistani and Bangladeshi) women are more susceptible to depression and anxiety compared to White women.3
There is evidence of a significant association between mental health conditions during pregnancy and maternal obesity. A meta-analysis published in 2014 found odds of antenatal depression and anxiety increased by 43% and 30%, respectively, in women with obesity compared to women of recommended BMI.4 The included studies were predominately from high-income countries (53 out of 62 studies), of which two focused on ethnic-minorities (African American and Hispanic);5,6 none focused on South Asian women. A systematic review7 investigating the effects of maternal anthropometrics on pregnancy outcomes in South Asians did not identify any studies on mental health conditions, further highlighting the lack of published data in this field.
In addition to the increased risk of mental health conditions among South Asian women, they also carry an increased risk of maternal obesity. In the UK, half of pregnant women enter pregnancy with a BMI in the overweight or obese range.8 Evidence suggests that South Asian women have the highest odds of first trimester obesity compared to White British women,9 and an increased risk of obesity-related complications, e.g. Gestational Diabetes Mellitus (GDM)7 during pregnancy at a lower BMI than White British women. The World Health Organisation (WHO) reflects this in their BMI criteria, where the categories for overweight and obesity are lower in South Asian groups (23-27.49 kg/m2 and ≥ 27.5 kg/m2 respectively)7 compared with the general population criteria (25-29.9 kg/m2and ≥30 kg/m2).10 The National Institute of Health and Care Excellence (NICE) guidelines have recommended the use of these lower WHO thresholds to identify and treat South Asian individuals with obesity-related illnesses;11 however, this is not reflected in pregnancy guidelines.
Given the increased risk for both obesity and mental health conditions in South Asian women, the aim of this study was to address the current research gap by investigating the association between antenatal depression and anxiety and early pregnancy BMI within and between South Asian and White British women, using data from the Born in Bradford (BiB) cohort.