Evidence showed maternal androgen levels in both healthy/general population and populations with hyperandrogenic disorders were inversely associated with offspring’s birth weight. We aimed to investigate the causal effect of maternal testosterone levels in general population on offspring’s birth weight and preterm delivery risk using two-sample Mendelian randomization (MR) method.

We obtained independent genetic instruments from a sex-specific genome wide association study with up to 230,454 females of European descent from UK biobank. Genetic instruments with consistent testosterone effects but no aggregate effect on sex-hormone binding globulin were used to perform the main analysis. Summary-level data of offspring’s birth weight with offspring's genotype adjusted was obtained from a study with 210,406 females of European descent. Summary-level data of preterm delivery was obtained from the FinnGen study (6,736 cases and 116,219 controls).

For outcome of offspring's birth weight, the numbers of instruments included in final MR analyses were 123, 128 and 91 respectively. For outcome of preterm delivery, the numbers were 115, 120 and 83 respectively. The present data files show the genetic instruments and their effects on exposures and outcomes. Pleiotropic genetic instruments that excluded in the MR analysis were also provided in the files.

Genetic instruments for testosterone were obtained from supplementary Tables of the study by Ruth et al (2020) (Nat Med. 2020 Feb;26(2):252-258. doi: 10.1038/s41591-020-0751-5). Summary data on birth weight has been contributed by the EGG Consortium using the UK Biobank Resource and has been downloaded from www.egg-consortium.org. The download link for summary data of preterm delivery can be obtained from https://finngen.gitbook.io/documentation/.