Missed Miscarrage(miscarriage) 6 weeks

Doctor, my partner Emma is 38 years of age and we had a 6 week embryo development failure (our first attempt for both of us and neither of us have any kids) we both understand the menstrual cycle and the 5 different hormones, since proven we can conceive, if we were to choose hCG and Progesterone treatment to boost hormone levels to maintain our next pregnancy, Q1: what is the procedure? Q2: are there risks? Q3: is it easy to check levels? Q4: if we had done the procedure before our 14 week 4 days missed miscarrage (miscarriage), is there a common trend still of missed miscarrages from the treatment? both myself and Emma wish to thank you in advance.