*This statement summarizes the third USPSTF recommendations for screening for chlamydial infection and the supporting scientific evidence, and it updates the 1995 recommendations contained in the Guide to Clinical Preventive Services, second edition (1).
Older adults may be more sensitive to the side effects of this drug, especially fast/pounding/irregular heartbeat. Current information shows that this drug may be used during pregnancy. Tell your doctor if you are pregnant because your dose may need to be adjusted. Levothyroxine passes into breast milk but is unlikely to harm a nursing infant.
Chris Smith, MD answered this Does Synthroid Cause Weight Gain? Hi. I recently had an increase in my Levothyroxine to 75mcg and after 3 weeks my tummy bloated so badly that I looked as if I was pregnant. I stopped the medication for 2 days and went back onto it after my doctor and friends told me off.