UTI during Pregnancy

Hello mommies I am 7weeks pregnant and meron po ako UTI riseta po sakin Ng OB-Gyne ko is Cefalexin Sabi nya safe nman daw Yun kaso ngwoworry talaga ako inumin baka Kasi mkasama sa baby ko since it's an antibiotics. Hindi po ba maaapektuhan Ang development Ng baby nun since during this time nagdedevelop na Yung brain nya?