Why do you think couples of New France has so many children?

It is a known fact that married woman of New france tended to have a baby approximately once every two years until they reached menopause. Why do you think this is?Why do you think couples of New France has so many children?
They were Catholic and even illegal abortions were usually not an option. In those days, your ability to survive was sometimes based on how many children you had--they tended fields, checked the traps, and generally made themselves useful from a very young age. Also, since many children died before age one, it was important to keep having children so that enough survived. Why do you think couples of New France has so many children?
Most French people are Catholic and do not practise birth control.