Purpose Stanford's Outcomes Research in Kids (STORK) is an ongoing prospective cohort of healthy pregnant women and their babies established to determine the effect of infectious diseases on weight, linear growth and immune system development during childhood. Additionally, a nested randomised intervention of household and personal cleaning products tests the effects of the microbicides triclosan and triclocarban on these outcomes and incidence of infection.

Participants Healthy pregnant women were identified and enrolled primarily at public clinics; their babies, enrolled shortly after birth, are followed to age 36 months. Automated weekly surveys assess daily health status, infectious disease symptoms, healthcare provider visits and antibiotic use, in the mother during pregnancy and the baby once born. At 4-monthly household visits, information and samples are collected from the mother (urine, stool, saliva, skin swab), the baby (blood by heel/toe stick, urine, stool, saliva, skin swab) and the household (environmental swabs). Annual blood samples are obtained by venipuncture (mother and baby). Medical charts are abstracted for allergy and infectious illness in the mother during pregnancy and the baby.

Findings to date From 7/2011 to 2/2015, 158 mothers were enrolled at approximately 20 weeks gestation; 127 babies were enrolled. Two-thirds of mothers are Hispanic, one-third are non-US born and one-third speak primarily Spanish; mean years of education is 13 (SD 6.2) years. Households have on average 4.5 residents. Most households (97%) were randomised to participate in the intervention. Completion of weekly surveys (86%) and follow-up (75% after 14 months) is excellent in this young, mobile population; collection of samples is ongoing with thousands of specimens stored.

Future plans Enrolled babies will be followed until age 36 months (last anticipated visit: 07/2018) with medical chart review completed soon thereafter. All epidemiological information and samples will be available for collaborative hypothesis testing.

Trial registration number NCT01442701; Pre-results.