I started on pens and moved to pump when I was about 14 weeks pregnant - it was a lot simpler on the pump to deal with the changes in dosage, but if the pump hadn't been an option I would have still gone for it. I was able to keep a low hba1c on pens (was down at 6.2 when we started trying to conceive), it just required a lot more injections and a relatively low carb diet. Given all the other sacrifices you have to make when pregnant (diabetic or not), a few extra injections isn't that much.
However when you see your DSN do tell them you are trying to conceive, as they may choose to put you on a pump to help.