{"doi":"10.1101/2024.10.14.24315464","title":"LABOR DURATION IS DEFINED BY THE TIME OF DAY OF LABOR INDUCTION","abstract":"BACKGROUND: Spontaneous labor and birth peak during the late evening and early morning hours, indicating an endogenous rhythm in labor onset and birth. We hypothesize that the time-of-day of labor induction will define labor duration and the risk of cesarian section. METHODS: In a retrospective study of pregnant women who were induced for labor (n =3,688), time-of- day of labor induction was studied across maternal phenotypes. Survival analysis and Cox Proportional Hazards model were used to identify differences in time-to-birth as a result of inducing labor at a specific time-of-day. RESULTS: Labor induction was circadian (p<0.05, Lomb-Scargle test), with a gradual lengthening in labor duration when labor induction was initiated later in the day, peaking at 23:00 hours (average labor duration of 20.72 hours) as compared to induction at 5:00 hours (average labor duration of 14.74 hours, p<0.01, Kruskal-Wallis test). The optimal time-of-day of labor induction was conditioned by maternal phenotype with significant differences in probability of giving birth as a result of the time-of-day labor was induced for nulliparous obese (p<0.05, Two-way ANOVA), and parous obese women (p<0.05). CONCLUSIONS: Labor duration in response to induction is circadian, with the shortest labor duration when induced during early morning hours. The optimal time-of-day of labor induction is conditioned by maternal phenotype and should be considered as a labor management practice.","journal":"medRxiv","year":2024,"id":492132,"datarank":0.10397207708399181,"base_score":0.6931471805599453,"endowment":0.6931471805599453,"self_citation_contribution":0.10397207708399181,"citation_network_contribution":0.0,"self_endowment_contribution":0.10397207708399181,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.8776,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1337956,"name":"Robert Long","orcid":"0000-0002-8693-1783","position":1,"is_corresponding":false},{"id":1338409,"name":"Isoken Olomnu","orcid":null,"position":2,"is_corresponding":false},{"id":327018,"name":"Rene Cortese","orcid":"0000-0001-9262-7828","position":3,"is_corresponding":false},{"id":409820,"name":"Hanne M. Hoffmann","orcid":"0000-0003-1555-1369","position":4,"is_corresponding":false},{"id":1036046,"name":"Kylie Cataldo","orcid":"0009-0000-8892-2613","position":0,"is_corresponding":true}],"reference_count":27,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-19T02:08:49.768795Z","pmid":"39484247","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}