Not nessisarily. I have been lactose intolerant my whole life, but I can have all the dairy under the sun while I'm pregnant. My mom has a disease called Multiple Sclerosis where she has to be in a wheel chair, but while she was pregnant she didn't need the wheelchair. Almost like pregnancy hormones counteract the MS. Its probably just how your body reacts to different things while pregnant.
Also, my doctor told me its better to intoduce a baby to cays well before they are one so they don't become allergic to them.