I wonder, are we simply underdianosing the women with autism as usual?
And I wonder if there's a correlation between drinking diet sodas (as opposed to naturally sweetened?) and getting your children evaluated for autism (like, say - diet soda drinkers are on average wealthier, and that correlates with better access to healthcare and more parental involvement, thus reducing underdiagnosis of autism?)
Given how sensitive obstetrics are to even small risks and how prevalent aspartame is, I'd be surprised if there is a genuine causal link here of such strong statistical effect. I mean, how many people use zofran? And yet obstetrics we're limiting its use in pregnant women just for a very very small alleged increase in the risk of heart problems in the baby.
To control for demographics they divided that ~15 into 6 different demographics (or 5 if male/female was already included, about 3 people per demographic if so).