hi in pregnancy in general usage of moisturiser is reccomended. this itching did it start afyer eating fish or something.does she have allergy issues. can take anti itching medication on prescription and calamine bath  for relief. but there are pregnancy specific situation of choestatic jaundice that is diagnosed by lft and urine test for bile salte which needs specific treatment and close follow up of foetus with nst. there can also be thyrotoicosis in pregnancy which is diagnosed by blood ft3 ft4 and tsh amd needs urgent treatment and close follow up of the neonate for first 3 months of delivery.