Correction to: Nature Genetics https://doi.org/10.1038/s41588-020-0631-4, published online 25 May 2020.

In the version of this article initially published, Table 1 was omitted from the PDF version but was present in the HTML version. In addition, reference 4 incorrectly cited Zhang, G. et al. Genetic associations with gestational duration and spontaneous preterm birth. N. Engl. J. Med. 377, 1156–1167 (2017); Zheng, J. et al. Recent developments in Mendelian randomization studies. Curr. Epidemiol. Rep. 4, 330–345 (2017) is the correct reference. Finally, some labels indicating high versus low power in the second and fourth graphs in Fig. 2c were switched. The errors have been corrected in the HTML and PDF versions of the article.