Hi My Daughter Is 31 Weeks And 2 Days Pregnant

hi my daughter is 31 weeks and 2 days pregnant she aving to having growth scans coz baby below centi line but there concerned man/nerve it as gt full name but there shotened it there told her on scan about this and something about shadoew on left hand side could you tell me wat this means we concered about the growth scan as she ad 2 small babys before its this nerve thing wen she was reading her notes