If thyroid control has not been performed or dysfunction is recorded, yet it is unknown whether control is sufficient or not:

Perform thyroid control!

R1.10 For women with T1DM seeking to conceive, recommend measurement of serum TSH and if thyroid peroxidase (TPO) status is unknown, anti-TPO measurement as well, before withdrawing contraception or starting trying to conceive. (1+)

Is thyroid control sufficient?