Untreated maternal hypothyroidism
can lead to preterm birth, low birth weight
, and respiratory distress
in the neonate. Thyroxine role helps in the normal development of the fetal brain and growth.
Administration of Levothyroxine
is the treatment of choice for maternal hypothyroidism. Pregnant women need larger doses due to the rapid rise in TBG levels resulting from the physiological rise in estrogen, the increase in placental transport and metabolism
of maternal T4 and the increased distribution volume of thyroid hormones. Women who already on thyroxine prior to pregnancy
usually need to increase their daily dosage, on an average, by 30-50% above preconception dosage.
Serum free T4 and TSH level
should be measured 1 month after the initiation of treatment. The thyroxine dose should be titrated to reach a serum TSH value of less than 2.5 mIU/liter while maintaining free T4 levels in the high normal range. You should follow up with your doctor every 4 to 6 weeks with free T4 and TSH value, till delivery.
After delivery you, most women should decrease thyroxine dosage received during pregnancy, over a period of approximately 4 weeks postpartum.
You should go to follow up with your THS and Free T4 levels to adjust your Thyroxine medicine dosage well to yourself.
Hope I have answered your query. Let me know if I can assist you further.
Dr. Heang Chan Raksmey, General & Family Physician