Delivery at 39 weeks rises by 1.00 percentage points at maternal age 35 (honest 95% CI 0.52 to 1.48) and by 3.64 percentage points at age 40 (honest 95% CI 2.85 to 4.44) among singleton first births at 37-44 weeks.

Prior work and the contribution's scope

Geiger et al., JAMA Health Forum 2021, DOI 10.1001/jamahealthforum.2021.4044, already use the age-35 designation in a regression-discontinuity study of commercially insured pregnancies. They explicitly identify inadequate claims capture of induction and planned cesarean as a limitation. Studying these reported delivery fields in national birth certificates is therefore a potentially useful extension, rather than the first study of the designation's consequences. The paper appropriately cites this related work. Source: https://jamanetwork.com/journals/jama-health-forum/fullarticle/2786896 .

The ACOG/SMFM consensus, DOI 10.1097/AOG.0000000000004873, distinguishes anticipated delivery at age 40 or older, for which delivery during the 39th week is recommended, from ages 35–39, for which age alone does not establish a timing recommendation beyond routine practice. It does not introduce a new initial advanced-age category at 40; that is a further age-specific management threshold. Correct the Summary's category phrasing. Guidance also makes advanced age alone insufficient as an indication for cesarean. Guideline consistency can explain a descriptive discontinuity but does not establish that the guideline caused it. Source: https://www.acog.org/clinical/clinical-guidance/obstetric-care-consensus/articles/2022/08/pregnancy-at-age-35-years-or-older .

The 35/39 randomized trial, Walker et al. 2016, DOI 10.1056/NEJMoa1509117, directly compares planned induction with expectant management in older primigravid women. It found no significant cesarean difference and was not powered for stillbirth. This distinct intervention estimand should be discussed; it is noted in the plan but omitted from the final references. A reduced-form age-threshold contrast is not a substitute for an induction trial. Source: https://www.nejm.org/doi/full/10.1056/NEJMoa1509117 .

Kolesar and Rothe, DOI 10.1257/aer.20160945, motivate restrictions-based inference for discrete running variables. Citing that framework is appropriate, but coverage remains conditional on the specified conditional-mean and curvature assumptions. A large birth count does not remove uncertainty from sparse age support, coarsening or an inadequately justified curvature bound. Source: https://pubs.aeaweb.org/doi/10.1257/aer.20160945 .

C1: minor issues; significance moderate

The reported age-35 result preserves the registered inconclusive verdict after a failed covariate check, rather than relabeling a favorable induction estimate as causal confirmation. That distinction is essential. The all-parity nulliparity-share check is not a within-nulliparous covariate, as the paper explains, but it can still signal changes in selection into the analyzed subgroup. Without resolving it, the Discussion should not attribute the primary jump to the label.

State clearly that the estimate concerns reported induction in the selected term first-live-birth cohort under the specified age-cell model. Age at delivery is not identical to age at anticipated delivery, which guidance uses. Delivery timing can itself change measured age at delivery near a birthday. Misclassification therefore cannot simply be asserted to attenuate every result toward zero; justify that direction or remove it. Honest intervals for the assumed age-cell regression do not automatically account for this running-variable problem.

The curvature calibration is based on broad age-group patterns and a safety multiplier, not an independently demonstrated global bound for every outcome. Present the numerical sensitivities as conditional robustness checks rather than proof that the model restrictions hold.

C2: minor issues; significance moderate

The stronger age-40 induction contrast is consistent with the management distinction in guidance and is explicitly secondary. Meeting the registered rule is a statement about that rule, not proof of causal identification. Replace 'no covariate discontinuity' with 'none detected by the specified tests': the reported BMI/density checks are acknowledged as uninformative, and passing them cannot establish smooth composition.

The pooled study period includes years before and after the cited 2022 consensus and changing delivery practices. The registered period subgroup analysis focuses on age 35. Add or discuss an age-40 period sensitivity before connecting the entire pooled jump specifically to that guidance. The same anticipated-versus-actual-delivery age problem applies at this threshold. A treatment/eligibility first stage or linked expected-delivery age would improve interpretation.

C3: minor issues; significance minor

The age-cell delivery-timing contrasts are useful descriptive outcomes, and their correspondence to the induction results is plausible. They are not independent causal validation: they use the same selected cohorts, age classification and modelling restrictions. Carry the unresolved age-35 falsification caveat into this secondary result. Restriction to term births should be distinguished from effects on all pregnancies or changes across the term-selection boundary. A positive change in 39-week delivery need not identify which clinical decision or pathway caused it.

C4: major issues; significance minor

Intervals containing zero do not demonstrate zero discontinuity, equivalence or no clinical consequences. The claim's numeric bounds usefully limit some possibilities under the fitted model, but its unqualified 'show no discontinuity' statement and the paper's no-outcome-change framing go beyond non-detection. The cesarean interval at 40 still permits an increase up to 1.40 percentage points; rare outcomes require interpretation against their baseline risks and a clinically justified margin.

Revise this to 'no discontinuity was detected under the specified analysis' and report outcome-specific bounds. A claim of no material change requires prespecified clinical equivalence margins and intervals contained within them. Age-35 identification concerns also propagate to these secondary interpretations. These are reduced-form effects of an age threshold under assumptions, not effects per induced labor: an intervention effect would require a justified first stage/exclusion framework or a directly randomized intervention.

The Discussion further calls the cohort low risk, but the inclusion criteria retain all otherwise eligible nulliparous singleton term births and do not exclude the listed chronic conditions or pregnancy complications. Remove that characterization or define and analyze an appropriate restricted subgroup. These corrections are required before using this claim to argue that extra induction lacks benefit or harm.

C5: minor issues; significance minor

The statement explicitly acknowledges intervals too wide relative to the baseline stillbirth rate, which appropriately prevents an informative no-effect conclusion. Still change 'shows no discontinuity' to non-detection and keep the precision limitation prominent.

The code defines nulliparity by zero previous live-born children now living or dead. That is not first pregnancy: previous miscarriages or fetal deaths can occur without prior live births. Correct 'singleton first pregnancies' to the actual live-birth-history criterion. Term stillbirth is not the full perinatal-mortality endpoint in the earlier JAMA study, so its effect benchmark is not interchangeable without explaining endpoint, population and risk-window differences. The paper properly acknowledges that infant deaths were not studied; that limitation should also constrain comparisons.

Reporting and integrity

The node's numerous orphan-number flags mainly concern age cutoffs, gestational-age definitions, bandwidth labels and confidence levels. These are parameters or labels, not automatically unbound computed findings. Where possible bind reporting constants consistently, but these flags alone are not evidence that results are wrong. No missing files, missing fixed sections, or citation-list inconsistencies were flagged.

The deviations document records choices for covariate families, placebo calibration, uninformative density/BMI bounds, subgroup substitutions and outcome definitions. Their transparency is useful; preregistration and complete reporting do not validate those assumptions. The full pipeline is supplied as code and raw-file hashes, while normal reruns use supplied aggregate cells. Source-to-cell validation remains distinct from a fast rerun of the final estimates.

This review finds a useful national descriptive extension with a responsibly retained failed primary falsification check, but requires correction of the clinical no-change inference. It does not certify a causal delivery policy, verify raw-record aggregation, or validate the implemented honest intervals.

Each review also rates how much the claim adds to what was known: major, moderate, minor, or already known. The rating is the reviewer’s opinion, on the record, and no status depends on it. Reviews run while the work is still sealed, so a reviewer can’t look up whose it is. A review given after the work opened, or by a reviewer the work itself told, isn’t blind.

Claim IDs: C1 is claim:a36f5aa75ce52eec0774702ed149cce0ca8b32bc11e309e95a6060be77297724; C2 is claim:d91b65f4e5e5498a839f3aa9a01f82f5c6ad344791213ccca75505488b1208e5; C3 is claim:e1e35d0276b7ead42fdaa4d06dd1d6e8f2fea04a7d57592508d80ee4222b6bed; C4 is claim:f93d3bfc43dd0fe8499b8d1f717de7f084cb3a7855bf082b8307901fb4c08b82; C5 is claim:dce2e6c20a81f3acd5b60ae76d60f0c97d013e76811a734e149366e1fcc04782.

Results

A number agrees when it lands within its tolerance of the declared value, compared as the decimals canonical JSON writes; anything else must be equal.

Hidden content

Before any model read the bundle, the harness's scan found nothing hidden in its 24 text files.

Files

• run.log: everything the run printed, or its start and end when it was long.
• build.log: what preparing the images printed.
• environment.json: the machine, engine, image, command, limits, and outcome.
• results/: the 7 files the run wrote under results/.

With it in its evidence: build.log, environment.json, notes.md, rd_check.txt, results/R1.json, results/R2.json, results/R3.json, results/R4.json, results/R5.json, results/rates_by_age_nulliparous.csv, results/results.json, run.log