Ectopic pregnancy is an important cause of maternal morbidity and mortality worldwide. To better understand the genetic risk factors underlying this pregnancy complication, we conduct a GWAS meta-analysis and identify two genome-wide significant loci on chromosomes 1 (rs4971091, p=5.32x10-9) and 10 (rs11598956, p=2.41x10-8). Follow-up analyses propose MUC1, an epithelial glycoprotein with an important role in barrier function, as the most likely candidate for the association on chromosome 1. We also characterise the phenotypic and genetic correlations with other phenotypes, identifying a genetic correlation with smoking and diseases of the (genito)urinary and gastrointestinal system, and phenotypic correlations with various reproductive health diagnoses, reflecting the previously known epidemiological associations.

The authors have declared no competing interest.

NPG was supported by MATER Marie Sklodowska-Curie which received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 813707. This study was funded by European Union through the European Regional Development Fund Project No. 2014-2020.4.01.15-0012 GENTRANSMED. Computations were performed in the High-Performance Computing Center of University of Tartu. We want to acknowledge the participants of the Estonian Biobank, and participants and investigators of the FinnGen study. The writing of this paper was supported by the writing retreats organised by the Institute of Genomics, University of Tartu.

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