{
  "abstract": "IntroductionGestational diabetes mellitus (GDM) is associated with significant maternal and neonatal morbidity. Screening strategies vary internationally and the diagnostic performance of the 50g glucose challenge test (50g GCT) as a universal screening tool remains uncertain across diverse populations.\n\nResearch design and methodsThis retrospective cohort study included 18,213 singleton pregnancies at a London tertiary hospital between 2010 and 2023. Women routinely underwent the universal two-step GDM screening pathway: a 50g GCT at 24-32 weeks gestation, followed by a diagnostic 75-g oral glucose tolerance test if the 50g GCT result was [≥]7.8 mmol/L. We evaluated the use of universal two-step screening in detecting GDM, how its prevalence varies with maternal characteristics, including ethnicity, body mass index, age, and in those who would not have been included in risk factor-indicated screening, and the association between the 50g GCT and adverse outcomes.\n\nResults2,015 women had an abnormal GCT, and 406 (20.1%) had an abnormal 75g OGTT, with GDM diagnosed at 24-28 weeks. We also found 87 women, despite a normal GCT and/or normal OGTT, developed late-onset GDM. The overall prevalence of GDM was 4.4% (810/18,213). Universal screening will therefore identify a significant number of GDM cases, notably including those in a low-risk cohort who would not have been screened using a risk factor-based approach. When we examined glucose as a continuous variable, there was an association between increasing 50g GCT values and adverse maternal and neonatal outcomes.\n\nConclusionUniversal screening with a GCT is a feasible and safe approach and addresses a significant health disparity gap, in that women without risk factors are screened and may be diagnosed with GDM. Given the long-term cardiometabolic implications of GDM, pregnancy diagnosis is important to allow for longer-term targeting of cardiometabolic risk factors to improve long-term health screening for type 2 diabetes and obesity.\n\nKey messagesO_ST_ABSWhat is already known on this topicC_ST_ABSO_LIGestational diabetes mellitus (GDM) is associated with maternal and neonatal morbidity, which is substantially reduced with early recognition and management. C_LIO_LIGDM screening approaches vary substantially in efficiency, diagnostic accuracy, and resource use. Universal screening with a 75g oral glucose tolerance test (75g OGTT) is resource-intensive, yet risk factor-based screening alone risks missing GDM in women without recognised risk factors. C_LIO_LIThe recurrence risk of GDM is up to 41.3%, and women with GDM are more likely to develop type 2 diabetes and cardiovascular disorders; therefore, diagnosis of GDM is important to identify and intervene in those women who are at higher risk. C_LIO_LIGDM is associated with increased offspring adiposity and childhood obesity, impaired glucose metabolism and a substantially elevated long-term risk of prediabetes and type 2 diabetes, as well as a broader adverse cardiometabolic profile. C_LI\n\nWhat this study addsO_LIUniversal screening detected GDM in women who may not have been offered screening based on risk factors. C_LIO_LIAround 1/3 of GDM cases detected in this population were diagnosed later in pregnancy following negative GCT and/or negative OGTT. C_LIO_LIThe relationship between maternal glycaemia and adverse pregnancy outcomes is continuous across GCT glucose levels, with risk increasing with increased glucose levels. C_LI\n\nHow this study might affect research, practice or policyO_LIFurther research is needed to investigate how a universal screening approach in diagnosing GDM addresses longer-term cardiometabolic health. C_LIO_LIVariation in the predictive value of a GCT for GDM by maternal characteristics should be considered when evaluating and optimising any universal screening strategy. C_LIO_LIA GCT population could form part of a hybrid GDM screening strategy where high-risk women proceed directly to 75g OGTT and women considered at low risk of GDM benefit from screening by GCT. C_LI",
  "abstract_shown": true,
  "affiliations": [
    "Imperial College London Department of Metabolism Digestion and Reproduction London, England, UK"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 11,
  "authors": [
    {
      "name": "X. Y. J. Tan"
    },
    {
      "name": "Y. X. Huang"
    },
    {
      "name": "M. J. Pandrich"
    },
    {
      "name": "G. Kerr"
    },
    {
      "name": "J. M. Thornton"
    },
    {
      "name": "R. A. Powell"
    },
    {
      "name": "J. Valabhji"
    },
    {
      "name": "A. L. Neves"
    },
    {
      "name": "N. M. Shah"
    },
    {
      "name": "M. R. Johnson"
    },
    {
      "affs": [
        0
      ],
      "name": "N. Singh"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4jbz1dmz3vz2f.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.06.26364834",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.10.06.26364834v1.full",
  "id": "4jbz1dmz3vz2f",
  "issns": [],
  "landing_url": "https://www.medrxiv.org/content/10.64898/2026.10.06.26364834v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "medrxiv",
      "obstetrics and gynecology"
    ],
    [
      "openalex",
      "2729|Gestational Diabetes Research and Management"
    ]
  ],
  "openalex": "W7220994535",
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.10.06.26364834v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-06",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4jbz1dmz3vz2f.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:22Z",
      "native_id": "10.64898/2026.10.06.26364834",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.10.06.26364834v1"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "medrxiv:obstetrics and gynecology",
      "subfield": "reproductive-child"
    }
  ],
  "title": "Universal Screening with a Glucose Challenge Test to Predict Gestational Diabetes Mellitus in a Diverse Population: A Retrospective Cohort Study",
  "title_text": "Universal Screening with a Glucose Challenge Test to Predict Gestational Diabetes Mellitus in a Diverse Population: A Retrospective Cohort Study",
  "type": "preprint",
  "updated_at": "2026-10-30T12:20:22Z",
  "url": "https://research.draconitic.com/paper/4jbz1dmz3vz2f",
  "venue": "medRxiv",
  "versions": []
}