Yes, you can get pregnant at 45. Being involved in the fertility field for 16 years I had cases when women conceived naturaly at 48 and even 52. It’s not only about ovarion reserve, it’s also about your health and hormone balance in your body. We all are very different and checking ovulation using saliva is the first step in the understading your body and capacity to conceive based on estrogen hormone level in the body.
You can get pregnant at 45. However, your chances of success are probably less than 5% each cycle and the chances of miscarriage are high. In 2015 over 2000 babies were born to mothers aged over 45 in the UK. Some of these women but not all will have had fertility treatment.