{
  "abstract": "Background: Parity is associated with differences in birthweight, but the magnitude and consistency of this association when expressed as birthweight percentiles remain incompletely characterized.\n\nObjective: To evaluate the association between birth order and birthweight percentile at both the population-level and within mothers across successive pregnancies.\n\nMethods: This retrospective cohort study included 130,718 singleton live births from 55,057 women delivering at a single tertiary medical center between 2012 and 2024. Birthweight percentiles were calculated using a national sex-specific reference. Linear mixed-effects models with a random intercept for mother were used to evaluate the association between birth order and birthweight percentile, adjusting for maternal age, infant sex, and maternal diabetes. Complementary longitudinal within-mother analyses evaluated changes in birthweight percentile across successive pregnancies.\n\nResults: Higher birth order was associated with higher birthweight percentile (β ≈ 0.074 SD per birth order increment, p < 0.001), corresponding to an average increase of approximately 3 percentile points per birth. The largest increase occurred between the first and second births, followed by progressively smaller but persistent increases with advancing birth order. This pattern was consistent across subgroup analyses and complementary within-mother analyses.\n\nConclusions: Higher birth order was consistently associated with higher birthweight percentile both across the population and within mothers. The association followed a distinct nonlinear pattern, with the largest increase occurring between the first and second pregnancies and progressively smaller but persistent increases thereafter. These findings provide a more nuanced understanding of parity-associated variation in fetal growth across successive pregnancies.\n\nSupplementary Information: The online version contains supplementary material available at https://doi.org/10.1007/s00404-026-08551-8.",
  "abstract_shown": true,
  "affiliations": [
    "Maternal-Fetal Medicine Unit, Department of Obstetrics and Gynecology, Mayanei Hayeshua Medical Center, Bnei Barak, Israel",
    "Gray Faculty of Medical & Health Sciences, Tel Aviv University, Tel Aviv, Israel",
    "Department of Mathematics, Bar-Ilan University, Ramat Gan, Israel",
    "Department of Computer Science, College of Management, Rishon LeZion, Israel",
    "Department of Computer and Software Engineering, Ariel University, Ariel, Israel",
    "Department of Obstetrics and Gynecology, Meir Medical Center, Kfar Saba, Israel"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 7,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Shanny Kolp-Asis",
      "orcid": "0009-0002-7895-2987"
    },
    {
      "affs": [
        2,
        3
      ],
      "name": "Oshrit Shtossel"
    },
    {
      "affs": [
        4
      ],
      "name": "Roi Yozevitch"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Karin Edut"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Ariel Lasry"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Avinoam Tzabari"
    },
    {
      "affs": [
        1,
        5
      ],
      "name": "Nissim Arbib"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6zecvbetnp42y.bib",
  "cited_by": 0,
  "doi": "10.1007/s00404-026-08551-8",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13748275/",
  "id": "6zecvbetnp42y",
  "issns": [
    "0932-0067",
    "1432-0711"
  ],
  "landing_url": "https://doi.org/10.1007/s00404-026-08551-8",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Research"
    ],
    [
      "openalex",
      "2735|Birth, Development, and Health"
    ]
  ],
  "openalex": "W7202358034",
  "pdf_url": null,
  "pmcid": "PMC13748275",
  "pmid": "43003952",
  "published": "2026-08-13",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6zecvbetnp42y.ris",
  "sources": [
    {
      "first_seen": "2026-11-13T12:25:58Z",
      "native_id": "PMC13748275",
      "source": "pmc",
      "url": "https://doi.org/10.1007/s00404-026-08551-8"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2735|Birth, Development, and Health",
      "subfield": "reproductive-child"
    }
  ],
  "title": "Association between birth order and birthweight percentile: population-level and within-mother analyses in a large birth cohort",
  "title_text": "Association between birth order and birthweight percentile: population-level and within-mother analyses in a large birth cohort",
  "type": "peer-reviewed",
  "updated_at": "2026-11-14T12:21:17Z",
  "url": "https://research.draconitic.com/paper/6zecvbetnp42y",
  "venue": "Archives of Gynecology and Obstetrics",
  "versions": []
}