This Week In Wellness researchers from the Smidt Heart Institute at Cedars-Sinai found that pregnant women who consumed a mediterranean diet were 28% less likely to get pre eclampsia, and 37% less likely to suffer from gestational diabetes, both of which can cause complications for both mum and baby. 

https://www.news-medical.net/news/20221222/Adherence-to-Mediterranean-diet-associated-with-lower-risk-of-preeclampsia-during-pregnancy.aspx

https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2799855