Objective: To determine if response to a low glycaemic index (GI) dietary intervention, measured by changes in dietary intake and gestational weight gain, differed across women of varying socio-economic status (SES).
Design: Secondary data analysis of the ROLO randomised control trial. The intervention consisted of a two-hour low-GI dietary education session in early pregnancy. Change in GI was measured using 3 d food diaries pre- and post-intervention. Gestational weight gain was categorised as per the 2009 Institute of Medicine guidelines. SES was measured using education and neighbourhood deprivation.
Setting: The National Maternity Hospital, Dublin, Ireland.
Subjects: Women (n 625) recruited to the ROLO randomised control trial.
Results: The intervention significantly reduced GI and excess gestational weight gain (EGWG) among women with third level education residing in both disadvantaged (GI, mean (sd), intervention v. control: -3·30 (5·15) v. -0·32 (4·22), P=0·024; EGWG, n (%), intervention v. control: 7 (33·6) v. 22 (67·9); P=0·022) and advantaged areas (GI: -1·13 (3·88) v. 0·06 (3·75), P=0·020; EGWG: 41 (34·1) v. 58 (52·6); P=0·006). Neither GI nor gestational weight gain differed between the intervention and control group among women with less than third level education, regardless of neighbourhood deprivation.
Conclusions: A single dietary education session was not effective in reducing GI or gestational weight gain among less educated women. Multifaceted, appropriate and practical approaches are required in pregnancy interventions to improve pregnancy outcomes for less educated women.
Keywords: Dietary intervention; Gestational weight gain; Health inequalities; Pregnancy; Socio-economic status.