Is it necessary to repeat ghusl if a transparent fluid is discharged an hour after intercourse, and then discharged again after a period of time, given that the questioner is four months pregnant?

What you saw was "madhy" (pre-seminal fluid), which is a clear, viscous liquid. It is impure (najis) and invalidates wudu' (ablution) but does not necessitate ghusl (ritual bath). However, if it was "mani" (seminal fluid), you are not required to repeat the ghusl.