Q: What does it mean if my basal body temperatures (BBT) are lower than average?

A: If your temperatures are lower than normal and you are not ovulating, that may be a sign of low thyroid hormone production (hypothyroid), which can cause some fertility and pregnancy problems.

An abnormal thyroid function before and during pregnancy, either too much or too little hormone can have a major effect both on your fertility and the developing baby. Obviously, it's best to diagnose and treat thyroid problems before pregnancy to improve both your fertility and your chance for a good pregnancy outcome.  Being diagnosed and treated can significantly enhance your chances of having a healthy baby.

Read More:
Fertility Charting - Basal Body Temperature BBT
Thyroid Disease and Pregnancy