So one of the more interesting readings I did in one of the most boring classes I took as an undergraduate (which was more the fault of the lecturer than the subject matter) was on medieval demographics, which show non-random patterns of both the spacing of offspring and the patterns of gender. In other words, families would delay having a child if they couldn’t afford to have them (especially given the already high rates of infant mortality at the best of times) and they would vary the number of boys and girls to meet the household’s needs for labor and potential liabilities when it came to inheritance and succession. Which is kind of mind-blowing if you had the mindset that medieval Europeans were all devout and dutiful Catholics adhering to strict doctrine.
Whether people were using herbal abortificiants or contraceptives or the pull-out method or infanticide, or to be more accurate what mix of these they were using, is a matter of scholarly debate.