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When conducted rigorously and interpreted carefully, pooled analyses can provide clinicians with a structured basis for risk communication that no single observational study could achieve alone. However, the methodological assumptions underlying meta\u2010analysis are frequently underappreciated, and their misapplication in teratological research carries real clinical consequences. This review critically examines both the promises and pitfalls of meta\u2010analysis as applied to clinical teratology with particular attention to the implications for clinical risk communication and decision\u2010making in teratology counselling. Drawing on selected examples from both the authors' work and independent research groups, we address key methodological concerns including study quality, heterogeneity, choice of statistical model, outcome classification, publication bias, confounding by indication, protopathic bias, the disproportionate influence of single large studies and the grouping of pharmacologically distinct agents within the same class. We also examine the conditions under which pooling is inappropriate and discuss the risk of outdated evidence shaping current practice. Uncritical reliance on meta\u2010analytic findings may lead to unnecessary discontinuation of beneficial medications, unnecessary termination of otherwise wanted pregnancies or reassurance that exceeds what the available evidence can legitimately support. Translating pooled estimates into meaningful counselling requires communication of absolute rather than relative risk, honest acknowledgement of uncertainty and shared decision\u2010making that incorporates the patient's circumstances, values and reproductive goals. Meta\u2010analysis should inform clinical judgement, not replace it.<\/jats:p>","DOI":"10.1002\/bcp.70822","type":"journal-article","created":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T06:15:06Z","timestamp":1790057706000},"source":"Crossref","is-referenced-by-count":0,"title":["When meta\u2010analyses mislead: Promises and pitfalls in teratology counselling"],"prefix":"10.1002","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0369-7934","authenticated-orcid":false,"given":"Yusuf Cem","family":"Kaplan","sequence":"first","affiliation":[{"name":"Terafar \u2013 Izmir Katip Celebi University Teratology Information, Training and Research Center  Izmir T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0009-3951","authenticated-orcid":false,"given":"Nusret","family":"Uysal","sequence":"additional","affiliation":[{"name":"Department of Medical Pharmacology Marmara University School of Medicine  Istanbul T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,9,21]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.3390\/pharma3040023"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmjopen\u20102013\u2010004365"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.phrs.2020.105229"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1186\/s12916\u2010017\u20100993\u20103"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.n71"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmjebm\u20102020\u2010111493"},{"key":"e_1_2_8_8_1","doi-asserted-by":"publisher","DOI":"10.1111\/bjd.14053"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.1002\/bdra.20533"},{"key":"e_1_2_8_10_1","doi-asserted-by":"publisher","DOI":"10.1002\/bdr2.2542"},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.1111\/bcp.15423"},{"key":"e_1_2_8_12_1","unstructured":"WebsterWS FreemanJAD.Is this drug safe in pregnancy?2001.www.elsevier.com\/locate\/reprotox"},{"key":"e_1_2_8_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.reprotox.2019.02.002"},{"key":"e_1_2_8_14_1","doi-asserted-by":"publisher","DOI":"10.1007\/s40264\u2010020\u201001027\u2010x"},{"key":"e_1_2_8_15_1","doi-asserted-by":"publisher","DOI":"10.1002\/cpt.158"},{"key":"e_1_2_8_16_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0066844"},{"key":"e_1_2_8_17_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pmed.1002742"},{"key":"e_1_2_8_18_1","unstructured":"SadlerTW.Susceptible periods during embryogenesis of the heart and endocrine glands."},{"key":"e_1_2_8_19_1","doi-asserted-by":"publisher","DOI":"10.1111\/bcp.13382"},{"key":"e_1_2_8_20_1","doi-asserted-by":"publisher","DOI":"10.1186\/1471\u20102288\u201014\u201025"},{"key":"e_1_2_8_21_1","doi-asserted-by":"crossref","unstructured":"DuvalS TweedieR.Trim and fill: a simple funnel\u2010plot\u2010based method of testing and adjusting for publication bias in meta\u2010analysis.2000;56.","DOI":"10.1111\/j.0006-341X.2000.00455.x"},{"key":"e_1_2_8_22_1","doi-asserted-by":"publisher","DOI":"10.4103\/0971\u20109261.316103"},{"key":"e_1_2_8_23_1","doi-asserted-by":"publisher","DOI":"10.7861\/clinmedicine.1\u20106\u2010478"},{"key":"e_1_2_8_24_1","doi-asserted-by":"publisher","DOI":"10.1348\/000711010X502733"},{"key":"e_1_2_8_25_1","doi-asserted-by":"publisher","DOI":"10.1046\/j.1445\u20102197.2003.02748.x"},{"key":"e_1_2_8_26_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.i4919"},{"key":"e_1_2_8_27_1","doi-asserted-by":"publisher","DOI":"10.3390\/jcm13164872"},{"key":"e_1_2_8_28_1","unstructured":"WellsGA SheaB O'ConnellD et al.The Newcastle\u2010Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta\u2010analyses. 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