Please post the reference range for the iodine test.
A TSH of 6.9 can indicate hypothyroidism. Since TSH is elevated, your wife's FREE T3 and FREE T4 should also be tested. FT3 and FT4 are the actual thyroid hormones and much more important than TSH.
Pregnancy puts more demands on the thyroid. So, if your wife's FT3 and/or FT4 are already low, it will be difficult for her to produce enough thyroid hormone for two. Maternal hypothyroidism can cause miscarriage and fetal developmental issues.
It would be best for your wife to have further testing, FT3 and FT4, before conceiving.