Not for me. My 2 very easiest pregnancies(3rd and 8th) resulted in totally different personality kiddos. My 3rd was extremely high needs as a baby and a rough and rowdy toddler/small child. She's almost 13yo now and has grown into a lovely and responsible young lady who is a joy to be around, but when she was little she was a challenge! Then my 8th was also an extremely easy pregnancy that resulted in an easy going, extremely happy little boy who sleeps, eats, and minds really well. He's so easy, night and day different than my 3rd was, but their pregnancies were extremely similar. Both times I was really dedicated to eating very healthy and exercising up till the end.
Actually when I think about it all of my pregnancies have been pretty easy, but those 2 that I stuck with the healthier habits I felt extra, extra vibrant and comfy.