Hi Catherine, Welcome to HelathcareMagic Forum.
Having a second child after 40 is no big deal. If this would be your second child, you wont have much complications but you should take a Good care of yourself. If your periods are regular, it means you are ovulating and you will have good chances of conceiving. Have Unprotected between the 10th and 20th day of your cycle because this is the most fertile period. Once you conceive get adequate rest and if you experience abnormal vaginal bleeding
report to your Doctor immediately.
All The Best, Take Care.