One situation is that two people really love each other and are ready to get married. At this time, they were pregnant before they got married, which was considered marriage. In this case, I believe that marriage is more reliable. Because they really intend to be together, they really want to walk into the marriage hall together. This child should be an unexpected surprise for them and should be especially expected, so they will wait for marriage and expect children. This is relatively ok. After all, they didn't rush to get married because they were pregnant, but after careful consideration, they really wanted to be together and stand the test.
Of course, there is another situation where the child is not a surprise, but a shock. Maybe both of them didn't do a good job of contraception, which led to the pregnancy of the child, and the man was responsible after pregnancy, so they thought of getting married. This kind of marriage may be unreliable, because they have no intention of getting married at all, they are forced to get married, and they are not ready to become real couples at all. Maybe in this case, two people will have many contradictions after marriage. After all, their running-in time may be short, so there will be more contradictions. In addition, the arrival of children has also brought them some pressure. They may be married reluctantly, so they may be unreliable.
Of course, if both husband and wife are responsible people and love each other enough, I think it is more reliable, because their love can stand the test and will become more reliable.