 If you have Hashimoto's thyroid autoimmunity, should you avoid fish consumption during pregnancy? Hi, this is Dr. Ruchon, let's discuss this question. Now, how does pregnancy relate to thyroid autoimmunity? In case you haven't heard this before, during pregnancy, thyroid autoimmunity can worsen or it can initiate because of the oscillation of the immune system that occurs during pregnancy. So, pregnancy is a high-risk time for thyroid autoimmunity. Now, the issue of fish consumption comes up because fish contain mercury, and there's discussion that mercury may provicate or may stimulate thyroid autoimmunity. So, some have asked the question, or made the caution, that perhaps we should avoid fish consumption because fish contains mercury during pregnancy, so as not to provoke a risky time where thyroid autoimmunity can worsen or could start. A recent study looked at this issue, and the researchers found something very interesting and very applicable in day-to-day life. They found that oily fish, and I'll put the abstract up here in the screen with some notes, they found that common oily fish actually prevented or decreased the incidence of thyroid antibodies or thyroid autoimmunity. So, the more oily fish these women ate, the less thyroid autoimmunity they had. And the oily fish they tracked in this study were salmon, mackerel, sardines, trout, and herring. All those fish were protected against thyroid autoimmunity. However, they noticed for swordfish, there was an increased incidence of autoimmunity, so the more swordfish they was eating, the more autoimmunity there was. This may come back to something known as the mercury selenium ratio. There are certain fish that will bioaccumulate more mercury and may have less selenium, and therefore be more risky for thyroid autoimmunity. The common oily fish listed in this study are a safe bet because they will have less mercury and or more selenium that will protect against the mercury. So, if you're a mother and you're concerned about thyroid autoimmunity, I would not recommend avoiding common oily fish as we've just gone through, because they can help with prevention of thyroid autoimmunity, and possibly more importantly, other studies have shown that consumption of fish transits to a higher IQ in the offspring. So, of course that's something that we want to be very mindful of as well. So again, pregnancy is a high risk time for thyroid autoimmunity to get worse or to begin. Mercury may make thyroid autoimmunity worse. Fish contains mercury, but not all fish are the same in this regard. Common oily fish like salmon, macro sardines, trout, and herring as the study found are protective, whereas other fish like swordfish, and we could also put in that category whale, although I'm sure not many people are eating whale, but in certain Asian cultures whale is eaten. Our mercury bioaccumulators have a lot of mercury and or have less selenium, they're more risky. So during pregnancy, I would eat fish, but eat the right type of fish that can help decrease your thyroid autoimmunity and have a positive impact on the IQ of your child. This is Dr. Ruscio and I hope this information helps you get healthy and get back to your life. Thanks.