It’s just the technical medical term. I don’t think “advanced maternal age” is much better (advanced age at 35?). Besides, advanced age is exactly what geriatric means.
Mother's age of 35 at estimated due date.
So, if the due date is beyond your 35th birthday but you give birth early it's still a advanced maternal age pregnancy.
My wife is a retired nurse ( American ), she uses that term when referring to such pregnancies.
so people feel better about having kids when its riskier?