(HealthDay News) -- The thyroid, a small gland at the base of the neck, helps regulate your body's metabolism, including how fast your heart beats.

An overactive (hyperthyroid) or underactive (hypothyroid) gland can lead to a host of health problems, particularly during pregnancy.

The National Women's Health Information Center lists these possible complications of an untreated thyroid problem during pregnancy:

Hyperthyroidism:

• Premature birth and early labor.
• Preeclampsia, which causes high blood pressure and problems with organs including the kidneys.
• A smaller baby or stillbirth.
• Increased heart rate of the fetus.

Hypothyroidism:

• Anemia.
• Preeclampsia
• Abnormal brain development of the baby.
• Maternal bleeding after giving birth.