King's College London

Research portal

Iodine status of pregnant women with obesity from inner city populations in the United Kingdom

Research output: Contribution to journalArticlepeer-review

Jessica Farebrother, Kathryn Dalrymple, Carolyn Gill, Sara White, Anna Brockbank, John H. Lazarus, Keith M. Godfrey, Lucilla Poston, Angela C Flynn

Original languageEnglish
JournalEuropean Journal of Clinical Nutrition
DOIs
Accepted/In press2020
Published12 Nov 2020

King's Authors

Abstract

Background/objectives: Iodine is essential for foetal neurodevelopment and growth. Requirements increase in pregnancy to support increased thyroid hormone synthesis for maternal and foetal requirements, and for foetal transfer. Iodine deficiency in pregnancy is widely reported, and obesity has been associated with sub-optimal thyroid function. We evaluated iodine status and its relation with birthweight in a secondary analysis of pregnant women with obesity from multi-ethnic inner-city settings who participated in the UK Pregnancies Better Eating and Activity trial (UPBEAT). Subjects/methods: Iodine and creatinine concentrations were evaluated in spot urine samples in the second (15+0–18+6 weeks, n = 954) trimester of pregnancy. We assessed iodine status as urinary iodine concentration (UIC) and urinary iodine-to-creatinine ratio (UI/Cr) and applied WHO/UNICEF/IGN population threshold of median UIC > 150 µg/L for iodine sufficiency. Relationships between iodine status and birthweight were determined using linear and logistic regression with appropriate adjustment, including for maternal BMI and gestational age. Results: Median (IQR) UIC and UI/Cr in the second trimester of pregnancy were 147 µg/L (99–257) and 97 µg/g (59–165), respectively. An UI/Cr <150 μg/g was observed in 70% of women. Compared to women with UI/Cr >150 µg/g, there was a trend for women with UI/Cr <150 µg/g to deliver infants with a lower birthweight (β = −60.0 g; 95% CI −120.9 to −1.01, P = 0.05). Conclusions: Iodine status of pregnant women with obesity from this cohort of UK women was suboptimal. Lower iodine status was associated with lower birthweight.

View graph of relations

© 2020 King's College London | Strand | London WC2R 2LS | England | United Kingdom | Tel +44 (0)20 7836 5454