Oostingh 2020.

Study characteristics
Methods	Study design: parallel‐group randomised controlled trial Setting: multi‐centre/hospital Study duration: July 2014 to March 2017 Sample size calculation: yes, but not achieved. Aimed for 3000 (general preconception cohort + subfertile cohort) in trial register. Aimed for 1000 general and 1000 subfertile in protocol: "based on our previous studies and the survey using Smarter Pregnancy, we expect a reduction of approximately 0.5 DRS points (based on a standard deviation of 2.7) in the intervention group compared to the control group. Considering alpha = 0.05 and power = 0.80, we will need to include a total of 916 women in our study (2 arms of 458 each). Due to expected dropouts of approximately 10%, we aim to include 1000 fertile (2 arms of 500 each) and 1000 subfertile women (2 arms of 500 each) in our study. For 50% of these women, we expect their male partner (n = 250 in each arm) to participate as well. Due to the lower SD (2.0) in men, with this sample size we are also able to demonstrate a reduction of at least 0.5 DRS points in the male partners"
Participants	Number of participants randomised: 848 (626 women and 222 men); 318 women and 116 men in control, 308 women and 106 men in intervention Baseline characteristics (mean ± SD) Control: median (IQR) age women: 33 (30 to 36), median (IQR) age men: 35 (31 to 41); lifestyle characteristics: median BMI (IQR) women: 23.8 (21.6 to 26.3), median (IQR) BMI men: 25.2 (23.3 to 28.3), adequate dietary risk score women: 56/318, adequate dietary risk score men: 12/116, adequate lifestyle risk score women: 175/318, adequate lifestyle risk score men: 26/116; fertility characteristics: not specified Intervention: median (IQR) age women: 33 (29 to 37), median (IQR) age men: 35 (31 to 49); lifestyle characteristics: median BMI (IQR) women: 23.7 (21.6 to 26.7), median (IQR) BMI men: 25.1 (22.7 to 26.9), adequate dietary risk score women: 49/308, adequate dietary risk score men: 17/106, adequate lifestyle risk score women: 175/308, adequate lifestyle risk score men: 27/106; fertility characteristics: not specified Baseline differences: no, study author replied by email that there were no baseline differences between groups Inclusion criteria: couples with indication for IVF/ICSI, age 18 to 45 years for women, no upper age limit for male participants, residing in The Netherlands, and having a smartphone with Internet access Exclusion criteria: "women and their male partners with insufficient knowledge or understanding of the Dutch language, who are treated by a dietician to lose weight in the context of a fertility treatment, and who have a specific diet (e.g. vegans)" Phase of fertility treatment: before and during fertility treatment
Interventions	Control: attention control Description: at baseline, at 12 and 24 weeks, participants in the control group receive the monitoring questionnaire about nutrition and lifestyle, but without feedback on the results. They receive access to a personal page and 1 seasonal recipe per week to maintain adherence and prevent dropout. Also, every 6 weeks, controls receive a request to adjust their pregnancy status if needed Intervention: combination of weight, diet, vitamin or mineral supplement intake (folic acid), alcohol intake, physical activity, and smoking Description: a personalised smartphone lifestyle coaching programme "Smarter Pregnancy". Through baseline and follow‐up lifestyle questionnaires (at 6, 12, 18, and 24 weeks) sent out via email, tailored lifestyle advice is generated. Tailored coaching includes a maximum of 3 interventions per week comprising text and email messages containing tips, recommendations, vouchers, seasonal recipes, and additional questions addressing behavior, pregnancy status, body mass index (BMI), or adequacy of the diet. Coaching is focused on study participants who report inadequate intake of vegetables and fruit and absence of folic acid supplementation, and those with unfavourable alcohol and smoking habits. Results from the questionnaires are shown on a personal online page to track a participant’s progress + the personal page provides access to additional modules (i.e. applications) to support physical activity, an agenda to improve compliance with hospital appointments and medicine adherence, and a module to monitor the safety of prescribed medication Duration: 6 months Frequency: multiple sessions, 2‐ to 3‐week email contact; screening at baseline, at 6, 12,18, 24, and 36 weeks Setting: individual + couple Mode of delivery: mobile app + email
Outcomes	Live birth: reported after request Reported behavioural changes in diet: numbers of men and women with adequate vegetable intake (> 200 grams/d), numbers of men and women with adequate fruit intake (> 2 pieces/d), measured at baseline, at 6 and 9 months, with online lifestyle questionnaire Reported behavioural changes in vitamin or mineral supplement intake: number of women with adequate use of folic acid supplement (400 mg/d) measured at baseline, at 6 and 9 months, with online lifestyle questionnaire Reported behavioural changes in alcohol intake: numbers of men and women not drinking alcohol measured at baseline, at 6 and 9 months, with online lifestyle questionnaire Reported behavioural changes in smoking: numbers of men and women not smoking measured at baseline, at 6 and 9 months, with online lifestyle questionnaire Reported behavioural changes in combination: a dietary risk score (DRS) comprising intake of vegetables, fruits, and folic acid supplement and a lifestyle risk score (LRS) comprising smoking and alcohol use (score from 0 to 9; the lower, the better) were calculated at baseline, at 6 and 9 months, from an online lifestyle questionnaire Clinical pregnancy: no further details on definition, measured at 12 months through questionnaire
Identification	Sponsorship source: Department of Obstetrics and Gynecology, Erasmus MC, University Medical Centre, Rotterdam, The Netherlands, a grant of ZonMW Health Care Efficiency Research and the Erasmus MC Mrace programme "Health Care Efficiency Research" Protocol available/trial registration: NTR4150 Country: The Netherlands
Notes	Study on general preconception population including subfertile cohort Study authors provided data on live birth as of February 2021. We contacted study authors for clarification of data on big 3 complications and raw data on vegetable and fruit intake in grams/d. We are awaiting reply as of February 2021
Risk of bias
Bias	Authors' judgement	Support for judgement
Sequence generation	Low risk	Quote: "for each stratum, a permuted block design is used and programmed before‐hand" Comment: computer generated
Allocation concealment	Low risk	Quote: "for each stratum, a permuted block design is used and programmed before‐hand. Hereby, allocation concealment is ensured" Comment: study authors contacted for more information; they replied: “allocation concealment was used to ensure that researchers did not know the order of group assignment at recruitment and randomisation. Moreover, researchers were blinded to the allocation of the participants”
Blinding of participants and personnel All outcomes	High risk	Comment: no blinding of participants and personnel (according to clinical trial register). Not clear from the paper if personnel delivering the intervention were blinded. Participants were aware of assigned intervention. Deviations from the intended intervention could have occurred
Blinding of outcome assessors Objective outcomes	Low risk	Comment: not clear if outcome assessors were blinded. Clinical pregnancy not likely to be influenced, as this is an observer‐reported outcome not involving judgement
Blinding of outcome assessors Patient reported outcome measures	High risk	Comment: outcome assessor is participant and is not blinded; reported behavioural changes are likely to be influenced. Eating healthy, moving, adequate use of folic acid supplement, not drinking, and not smoking are socially desirable
Incomplete outcome data	Unclear risk	Quote: "intervention: lost to follow‐up (n = 13) due to incomplete answers; ♦Women, n = 10 ♦Men, n = 3. Discontinued intervention (n = 125) ♦Women, n = 97 ♦Men, n = 28. Control: lost to follow‐up (n = 14) due to incomplete answers; ♦Women, n = 9 ♦ Men, n = 5. Discontinued intervention (n = 79) ♦Women, n = 61 ♦Men, n = 1" Comment: ITT analysis, but study authors did not impute on ITT those lost to follow‐up; we assumed in our analysis that they did not have a clinical pregnancy. Missing data documented but not balanced between groups. 30.2% in intervention group vs 18.2% in control group. Reasons for discontinuation not reported
Selective outcome reporting	High risk	Comment: prospectively registered study protocol is available. Most outcomes are analysed and reported in accordance with the protocol. However, tertiary outcomes are reported in the protocol and not in Netherlands Trial Register. Additionally, study authors reported an outcome not pre‐specified in the protocol: lifestyle risk score, and did not (yet) report on the pre‐specified outcome: BIG 3 complications
Other sources of bias	Unclear risk	Not clear which lifestyle questionnaire was used, and if this questionnaire was validated