Whoah, there's a lot of people guessing on this thread, some of whom should know better (that's intended as a gentle rebuke - you know who you are
).
You said right up front that you are self employed. The term 'wage' is therefore totally meaningless for you, the money you take out of the buisness is rightly called 'drawings'.
Maternity allowance is paid while you are on Maternity Leave i.e. not working. If your business can sustain itself without you working in it (e.g. by your husband acting as an unpaid employee, which is itself perfectly legal as long as he is not claiming Job Seekers Allowance or other benefit on the basis of not working), then you can continue to earn income while you are not working, just the same as you continue to earn income from savings, investments, shares etc.
YOU DO NOT PUT MATERNITY ALLOWANCE ON YOUR TAX RETURN
So take whatever drawings you like while you are on MA. Make sure that you don't do any work during your maternity leave, and that there is plenty of evidence (emails etc.) that your DH has been doing it all in case DWP (not HMRC, they are not concerned with MA) investigate.
You could try ringing a Jobcentre Plus, but they are notoriously bad at understanding the rules for self employed people claiming MA.
Talking to an accountant might be a good idea, it may well be that either or both of your business would be more tax efficient if they were run as limited companies.