Risk of birth defects increases a lot with age of both parents. The number (and percentage) of advanced age pregnancies (I think it's defined as >35) has increa

Risk of birth defects increases a lot with age of both parents. The number (and percentage) of advanced age pregnancies (I think it's defined as >35) has increased over that time[1]. This confounder is virtually guaranteed to account for a lot of that doubling. How much? No idea. Back to my overarching point. [1] https://evidencebasedbirth.com/wp-content/uploads/2021/05/Figure1_AMA_2021-blog_v2_wm.png https://evidencebasedbirth.com/wp-content/uploads/2021/05/Fi...