Need advice on retention bonus and parental leave

I’m fortunate enough to receive a retention bonus that requires me to stay at the company for 2 years. If I leave voluntarily or get fired for cause in that period, I have to repay this bonus. The bonus is contingent on my employment and not on meeting performance targets. One thing that is not clearly spelled out is how taking parental leave (maternity or paternity, leaving it gender neutral for now) will affect it. For example, what happens if I take a 4-month parental leave during these 2 years? I don’t want to raise it to instigate questions about my personal life... is this something I should bring up voluntarily?