I like pregnancy before marriage in the sense that you have already known that you wife to be is fruitful. Pregnancy before marriage also is also good because as a man you know that your manhood is also active. Pregnancy before marriage also shows that you are in a safe relationship that will produce children. Though marriage before pregnancy is also good but the danger of unfruitfulness will take its toll on you if your wife delays in getting pregnant.
I have known cases of people who would directly divorce their partners because they would not be able to have children, which are always heartbreaking.
Though, in this new generation of young people in the west, there are many who do not actually seek to have children actively. Actually, much of this Z generation rather first to secure financial stability before going for the expansion of the family.
Some of my friends have that mindset and I believe I share some of the benefits and reasons why people may want to stay childless. As long as both the man and the woman of the relation are okey with it, I don't see any problem with it.