Speaking from experience, I have dealt with many clients who have had children whilst they are subject to IVA proceedings, and each case probably had its own differences.
As Ian has already advised you, early communication with yoru IP is the key, and to have a sensible meeting you would do well to have explored the amount of benefits you are entitled to receive and the additional costs you are likely to incur - including childcare if you are intending to return to work.
It is time to perhaps reassess priorities, but if you do wish to continue with the IVA and you feel that you can afford to make some form of repayment into the future, then perhaps a variation meeting will be necessary to see if creditors are prepared to accept a lower offer.
Regards, Melanie Giles, Insolvency Practitioner