Plutzer 2008.

Methods	Randomised controlled trial (Cavity Free Children Trial; multi‐arm trial with 3 arms; low and high intensity group combined for inclusion in review meta‐analysis)
Participants	649 pregnant women and their fetuses were randomised (all included in this review). Inclusion criteria: nulliparous women pregnant women attending regular antenatal visits at the participating teaching (public) hospitals (most women were in their 5th to 7th months of pregnancy) Exclusion criteria: high risk and multiple pregnancies; improperly completed questionnaires and mother's inability to comprehend written English Setting: Teaching (public) hospitals in Adelaide, South Australia (participants recruited in 2002)
Interventions	Group 1 (n = 165 women randomised) Women received printed information about oral health applied in the form of anticipatory guidance at enrolment into the study. The information included messages focused on their own oral health and nutrition during pregnancy, healthy diet advice for young infants and children, and information about healthy feeding practices (e.g. pacifiers, infant sleep and importance of primary teeth for infants). At 6 months postpartum they received anticipatory guidance about oral health for infants via mail, reinforced during a scripted telephone interview which also included consultation on issues arising in the interview. Women received a third round of guidance, focused on oral health of 12‐month children, at 12 months postpartum. Group 2 (n = 162 women randomised) Women received the same interventions as women in Group 1, however no structured telephone interview/advice; n = 156 women, randomly assigned after second round advice was provided. We combined these two groups for inclusion in this review. Group 3 (n = 322 women randomised) Women received standard care. Intervention timing: one session delivered during pregnancy (5 to 7 months); subsequent sessions at 6 and 12 months postpartum (> 6 months intervention duration) Theory or model used as a basis for intervention: Nowak 1995 model of anticipatory guidance delivered by paediatricians and family physicians in well childcare clinics in the early years to improve oral health in young children
Outcomes	Data in meta‐analysis for: primary outcome: caries presence in primary teeth; dmfs index; dmft index; SiC30 index; secondary outcomes: none Additional narrative text for: none Tabulated data for: child dental attendance; change in mother self‐reported oral health behaviours (including diet) and attitudes; adverse events for mother or child Additional outcomes that had not been prespecified: Child: type of dental provider, child receipt of anaesthetic for dental treatment, infant health at birth (gestation at birth, birth weight, sex, race, congenital abnormalities, Apgar score and resuscitation at birth). Mother: access to oral health information; maternal health at birth of study child (gestation at first visit, blood pressure, hospitalisation during pregnancy, onset of labour, postnatal hospital stay, some laboratory results not further specified)
Notes	Funding: Chanel 7 Children's Research Foundation of South Australia, Colgate Oral Care, Johnson & Johnson Pacific Company and The University of Adelaide Declarations of interest: none declared Groups 1 and 2 combined for inclusion in the review analyses
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A random number table was used to allocate women into test or control groups (before their consent was sought as Zelin RCT design).
Allocation concealment (selection bias)	High risk	Zelin RCT design
Blinding of participants and personnel (performance bias) All outcomes	High risk	Zelin RCT design Quote: "The potential participants were randomly allocated to the test and control groups, then approached about the aims of the study and their group allocation. They had the opportunity to accept or refuse the group to which they were randomly allocated. Lack of blinding and potential loss of statistical power (if many participants refuse the allocated group) are the main disadvantages of the design".
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "To assist with blinding the examiner from knowing the characteristics of the child (test/control group), the examinations were organized through a dental receptionist who received the examination schedules".
Incomplete outcome data (attrition bias) All outcomes	High risk	75.4% of the intervention group infants and 66.8% of control group infants were available for the caries assessment at 20 months of age. 96/327 (29%) and 91/322 (28%) of infants of mothers randomised to the intervention and control groups respectively were available for the caries assessment at age 6‐7 years; 117/327 (35%) and 113/322 (35%) were available for the dental visit outcome assessment.
Selective reporting (reporting bias)	Unclear risk	Without access to a study protocol, we were unable to confidently assess reporting bias.
Other bias	Low risk	The authors reported that after being told their group assignment (Zelin design), very few participants switched groups. Considering group imbalance, the authors reported that: "The only significant differences between the groups at baseline were in the use of dental floss (31.6% in the test group used versus 22.6% women in the control group; chi square P < 0.01) and in the use of alcoholic drinks during the pregnancy (12.4% in the test group compared with 7.4% in the control group; chi square P < 0.05)". Additionally, analysis comparing participants in the intervention and control groups included in the 6‐7 year outcome assessment showed no significant difference between the groups in key characteristics.