This article is supposed to give the key to "morning sickness".
If the report is true....babies born of MS Mums will be lower birth weight!
Am just going on my experience, but I suffered more from MS on my second and third pregnancies....This has nothing to do with morning sickness. Mums of second, third, etc babies have another child to consider. I think the sickness is down to the mother of a second child being unable to rest completely.
I know if my second pregnancy had been my first there were things I would not have had "kittens about".
To my mind...parenting is a hard job...and the longer you keep at it...the better your progeny are!