Can Pregnancy Occur From Precum During Penetration With A Single Layer Of Underwear Soaked In Vaginal Fluid, Especially With Irregular Periods?

Hi since i see of lot of questions a if sperm can travel trought clothes. There are almost none where it describes the exact situation im interested in. Will it be much more likely if penetration is happening but still with a single layer saturated from vagina fluid underwear between. How likely to get pregnant this way without ejaculation just precum also she has very irregular periods sometimes as much as 6 months without a period