Wife's lost libido is rubing off?

My wife lost her desire to have while pregnant with our son (now 1 yr old) and it hasn't returned. We have talked honestly about both our needs, I do as much as possible around the house, etc. etc. etc. I used to do my best not to pester her, but a week was about my limit before I'd try to initiate. We even agreed that once a week was a reasonable frequency for both of us, but this rarely materialized. To her defense, we have extremely busy lives. Now it's been 4 1/2 weeks and I feel no desire to initiate. Is this a good thing or a bad? Could it be a defense mechanism against rejection? Or should I just wait and see how long it takes her to wonder what's going on? Anyone with similar experiences?