Age
A woman's fertility declines with age. This is due to a number of factors, including decreasing egg quality and increasing levels of follicle-stimulating hormone (FSH). FSH is a hormone that helps to regulate the menstrual cycle. As FSH levels increase, the ovaries become less responsive to it, and ovulation becomes less likely.
Health
A woman's overall health can also affect her fertility. Certain medical conditions, such as polycystic ovary syndrome (PCOS) and endometriosis, can make it difficult to conceive. Other factors that can affect fertility include sexually transmitted infections (STIs), obesity, and smoking.
Personal circumstances
A woman's personal circumstances can also play a role in how many children she has. Some women may choose to have only one child because they want to focus on their career or because they don't want to deal with the challenges of parenting multiple children. Other women may have several children because they want a large family or because they believe that having more children will make them happier.
Ultimately, the number of children a woman has is a personal decision that should be made based on her own individual circumstances. There is no right or wrong answer, and the best decision for one woman may not be the best decision for another.