Thanks for your query.
I read your query and I understand your concerns.
There is no concept like weak or strong fertilization. 31 years is not a old age. I dont think there is any problem with egg formation.
If there is miscarriage
once, it does not necessarily repeat. If there is miscarriage again, we can think about treatment options. There is no need of anything like that as of now.
Hence I suggest you please try for pregnancy
again and it is possible that your wife will conceive.
All the best.
I hope I answered your query. I will be available for any followup queries you have.
IVF & Infertility