Please seek the advise of a qualified Obstetrician and an Endocrinologist.
The thyroid gland produces hormones that are important for daily functions and well being. At periods of stress or increased demand like puberty, pregnancy, the need for thyroid hormone goes up and the gland has to work more.
The values you are referring to would be the TSH value. A high TSh value 20 or 10 suggests HYPOTHYRIODISM that is know to produce constipation and is linked to miscarriages.
A word of caution.
Interpretation of thyriod reports depends on the lab normal range units, it may vary based on the kit used.
Please see the specialists mentioned above. They would assess you wife, carry out further tests like T3, T4, TSH and Free T4 with an ultrasound of the neck and advise you accordingly. Based on all the reports, she would be prescribed thyroid hormone supplements in the appropriate dosage in the form of tablets.
Please attend the check-ups regularly because HYPOTHYROIDISM IN THE MOTHER CAN IMPACT THE GROWTH AND WELL BEING OF THE CHILD IN THE WOMB. Given that there have been two miscarriages, many experts would suggest to treat this pregnancy as a precious pregnancy which basically means extra care, monitoring and more frequent follow-ups.