Neonatal Outcomes Following a Preconception Lifestyle Intervention in People at Risk of Gestational Diabetes: Secondary Findings from the BEFORE THE BEGINNING Randomized Controlled Trial

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Title, Abstract And Keywords:

The title expresses clearly what the study is about; the abstract summarizes properly the contents discussed and key words cover the main themes considered.

Introduction: 

It might be appropriate to provide a more comprehensive description of time-restricted eating, referring to its main characteristics and including reference to the supporting evidence in literature, as it represents the main dietary intervention of this trial.

Materials and methods:

With regards to participants recruitment, It could be relevant to include bibliographical reference to Norwegian guidelines’ criteria for elevated risk of gestational diabetes mellitus.

Concerning dietary data collection through food diary, it can be suggested to provide a more detailed description about methods or software used to calculate energy daily intake.

Discussion: 

Discussion fit with the aims of the study since it focuses on neonatal and body composition outcomes in newborns, after lifestyle intervention during pregnancy and preconception window.

In the section about limitations of the study, authors correctly referred to bioelectrical impedance analysis as a safe, cost-effective, rapid and practical instrument which, although, tends to underestimate fat mass and overestimate fat-free mass compared with other gold-standard methods such as air-displacement plethysmography or dual energy X-ray absorptiometry (1,2)

1. Demerath, E. W., Fields, D.A. Body Composition Assessment in the Infant. American Journal of Human Biology. 2014; 26: 291-304
2. Jerome, M. L., Valcarce, V., Lach, L., Itriago, E., Salsa, A. A. Infant Body Composition: A Comprehensive Overview of Assessment Techniques, Nutritional Factors, and Health Outcomes. 2023; 38: S7-S27.

Author Response

Please see attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for the opportunity to review this article. Certainly interesting results. Is appreciated that you put this together for publication despite the findings as important to report on.

Was there evidence supportng that time restricted eating and exercise works generally to decrease weight.

Line 264 is there anything that can be ascertained from this that could be changed to have a better overall affect.

Line 267 what are the implications fo this study to the current study and therefore could be changed to have a bigger effect.

Adherence to intervention - what then is the implication. There has been some work in US looking at lifestyle changes re diet and exerecise that is easier for people to incoportate and therefore adhere to which may be inportant to consider here.

Certainly an interesting paper so well done.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Reviewer comments

1. The study was powered for a maternal glucose tolerance outcome, not for the neonatal outcomes reported here. The sample size (n=106 births) is likely insufficient to detect clinically meaningful differences in the primary outcome (proportion of infants with birth weight >4kg) and other secondary neonatal endpoints, increasing the risk of a Type II error.
2. The explicit statement that participants, investigators, and outcome assessors were not blinded to group allocation is a significant methodological weakness, as it introduces a high risk of performance and detection bias, especially for subjectively assessed outcomes.
3. The loss of 60 out of 167 randomized participants (36%) between randomization and the birth analysis, coupled with the noted decline in intervention adherence during pregnancy, compromises the validity of the intention-to-treat analysis and the overall intervention effect.
4. The use of Bioelectrical Impedance Analysis (BIA) for infant body composition is a major limitation. BIA is known to be less accurate than gold-standard methods (like ADP or DXA) in neonates, potentially introducing measurement error and obscuring true between-group differences.
5. While adherence is mentioned as declining, the manuscript lacks a clear, consolidated presentation of quantitative adherence data (e.g., average PAI scores achieved, proportion of days adhering to TRE) throughout the preconception and pregnancy periods for the entire cohort.
6. The analysis of multiple secondary outcomes increases the chance of false-positive findings. While a significance level of p<0.01 was applied, a more robust method for controlling the family-wise error rate (Bonferroni correction) for this family of neonatal outcomes is not mentioned.
7. The participants were enrolled based on various risk factors for GDM (primarily BMI ≥25), leading to a heterogeneous cohort in terms of metabolic risk at baseline, which may dilute the intervention effect.
8. Beyond adherence, there is limited information on the actual fidelity of the intervention delivery (e.g., quality of supervised sessions, consistency of counselling) and any contextual factors that may have influenced its implementation.
9. Some results, like the absolute 7% reduction in macrosomia and the 159g lower mean birth weight in the intervention group, may be clinically relevant but are dismissed as non-significant, highlighting the power issue. The discussion could better contextualize this.
10. The cohort was predominantly of European origin, well-educated, and from a single center in Norway, which limits the generalizability of the findings to more diverse populations with different healthcare systems and cultural contexts.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Accept in present form