Pregnancy success is women dependent (egg quality is the problem, and leads to increasing fertilitization and miscarriage rates) and start to drop at the beginning of one’s 30s and gets really bad in late thirties and near impossible in early 40s. Every women is different and some have earlier falloff in success rates. The moral of the story is don’t want until you are 30 to have kids. Have them young and it is easy. Wait and it gets really emotionally hard or impossible or expensive or a combination of all three.

https://advancedfertility.com/patient-education/causes-of-in...