Table 2.

Schedule of study assessments and procedures

	Screening*	Enrolment*	Home screen and installation	Birth	Baseline (±1 week)	4 weeks (±1 week)	3 months (±2 weeks)	6 months (±2 weeks)
Confirm eligibility	X	X			X
Verbal consent to collect contact details and access antenatal records	X
Written informed consent		X			X
Demographic data	X				X
Engineer home assessment			X
Install water softener			X
Randomisation			X
Visible eczema status						X	X	X
Blinded eczema severity assessment (EASI)						X	X	X
DNA collection from buccal swab						X
Antenatal factors questionnaire		X
Acceptability and feedback questionnaire								X
Invite to participate in semistructured interview about study								X
Collection of skin and nasal microbiome swabs					X	X	X	X
TEWL measurement‡					X	X	X	X
Cutaneous tape stripping‡					X	X	X	X
Skin pH measurement‡					X	X	X	X
ATR-FTIR measurement‡					X	X	X	X
Skin surface hydration‡					X	X	X	X
Monthly infant skin and health† questionnaire, including Patient-Oriented Eczema Measure (POEM) score					From 4 weeks to 6 months of age
Weekly water samples (in intervention arm)			From installation to 6 months of age

*Screening and enrolment may occur at the same visit if participant prefers and if investigator agrees.

†Any other concomitant illnesses that develop during the study including episodes of respiratory, gastrointestinal and other acute illnesses.

‡At Guy’s and St Thomas’ Hospital site only.

ATR-FTIR, attenuated total reflectance Fourier transform infrared; EASI, Eczema Area and Severity Index; POEM, Patient-Oriented Eczema Measure; TEWL, transepidermal water loss.