I echo Trav. If I'm blessed to have more and haven't cleared the Lyme yet, I will take amoxicillin to be safe.
I had one child while in my young 20s, before I knew I'd had Lyme since I was 8. She was born perfectly healthy, is brilliant, beautiful, all the good stuff.
The only thing I can now relate to Lyme is that I had overwhelming nausea and exhaustion for all 9 months of the pregnancy and couldn't gain weight. Food made me sick; I gained only 11 pounds for an 8-pound baby! I bet that was the untreated Lyme playing a role.
Best of luck to you, and try not to worry too much during what should be a very happy time!