INTRODUCTION: This study examined maternal, delivery and infant factors associated with cord thyroid-stimulating hormone (TSH) concentrations in an Asian population. METHODS: The Growing Up in Singapore Towards healthy Outcomes (GUSTO) study is a mother-offspring birth cohort from 2 major hospitals in Singapore. Cord serum TSH was measured using the Abbott ARCHITECT TSH Chemiluminescent Microparticle Immunoassay and the ADVIA Centaur TSH-3 Immunoassay. After excluding infants with a maternal history of thyroid disease, screening cord TSH results from 604 infants were available for multivariable regression analysis in relation to the factors of interest. RESULTS: Babies born by vaginal delivery had significantly higher cord serum TSH concentrations than babies born by caesarean section. Cord serum TSH concentrations differed significantly by measurement method. There was no association of cord TSH concentrations with ethnicity, sex, birth weight, gestational age, maternal body mass index, gestational weight gain, gestational diabetes mellitus status and other maternal, delivery and infant factors studied. CONCLUSION Interpretation of cord serum TSH results may need to take into account mode of delivery and measurement method.

Given the consensus that there is a causal relationship between Zika virus (ZIKV) infection in pregnancy and congenital Zika syndrome (CZS), clinicians must be prepared to manage affected patients despite the numerous gaps in current knowledge. The clinical course in pregnancy appears similar to that in non-pregnant women, although viraemia may be prolonged. ZIKV infection can be diagnosed by serum and urine reverse transcription-polymerase chain reaction, but commercially available serological tests are currently unreliable in dengue-endemic regions. Although vertical transmission can occur at any time during gestation, first- and second-trimester infections have the highest risk of developing central nervous system anomalies. Aberrant fetal growth and pregnancy loss may also occur. Serial ultrasonography should be conducted for infected cases. Without a vaccine, pregnant women should be advised to minimise mosquito bites and reduce sexual transmission risk. Overall, the absolute risk of CZS arising amid a ZIKV outbreak appears relatively low.