heavy eight tends to reduce production of reproductive hormone

that is why overweight and obese people may have a high time getting pregnant.
A couple of mine have tried years without success. The wife has too much fat, it seems. That time I do not know the relationship. But if I have a chance, I would recommend the wife to lower her weight.
160 pounds is not a problem for everyone. But you may consider lowering your weight to see what happens. Try to recall what weight you had when you got pregnant the first time.