Does CPC re-evaluate the LICO if there is an addition in sponsor's family (child birth) while immigration case for parents sponsorship is still in process.???

As per Paragrahp 134 (2) of Immigration and Refugee Protection Regulations

Change in circumstances

(2) If an officer receives information indicating that the sponsor is no longer able to fulfil the sponsorship undertaking, the Canadian income of the sponsor shall be calculated in accordance with paragraph (1)(c) on the basis of the 12-month period preceding the day the officer receives that information rather than the 12-month period referred to in that paragraph.
http://laws.justice.gc.ca/en/I-2.5/SOR-2002-227/133253.html#rid-133269