March 24, 2023

30% increase at the start of pregnancy. Follow up with your PCP every 4 weeks.

When a person who has hypothyroidism becomes pregnant they need to increase their levothyroxine dose by 30 now why is this the case to understand this you need to understand what thyroid dysfunction actually is we have an organ in our neck here called the thyroid its function is to secrete energy molecules called t3 and t4 that go throughout our bloodstream and

Essentially energize our body to make energy now the mantra is your brain particularly an organ called the hypothalamus in your brain secretes tsh a molecule called thyroid stimulating hormone it goes down to your thyroid acts on its receptors and engages the thyroid become active and produce the t3 and t4 also called thyroid hormone to go across your bloodstream

And into your cells and produce energy so if it’s working right tsh comes from your uh head it goes to your thyroid stimulates it to produce t3 t4 and out goes these molecules to your body cells and create energy however if your thyroid is not working right then no matter how much tsh is coming into it it’s not going to be making these t3 and t4 molecules to

Energize your body and therefore you need synthetic thyroid hormone also called levothyroxine and this you need this in something called primary hypothyroidism primary because it’s affecting your thyroid primarily and hypo as in the function is decreased of your thyroid so in pregnancy you can think why do you need extra levothyroxine well as a whole now you

Need energy not only for the mother but you need it for the baby as well so overall you do need extra energy so increase your level thyroxine but at a physiological level there’s a lot more going on there’s a little more nuance to this when someone becomes pregnant they have this increase in a hormone called beta-hcg this beta-hcg has different effects but it

Also does oddly act like the tsh molecule i mentioned before the tsh molecule coming from your hypothalamus stimulating your thyroid hormone so if you have extra beta hcg it’s going to act like tsh and make your thyroid go into overdrive and make more t3 and t4 which is actually what you want during pregnancy um because you want extra thyroid hormone for mom

And the baby however um too much again is not great either everything in moderation so you have another hormone during pregnancy called estrogen and this increases a molecule called tbg thyroid beta globulin this is kind of like a buffer in your bloodstream um the more thyroid beta globulin you have the more it can bind to extra unnecessary t3 and t4 thyroid

Hormone being produced and keep your thyroid hormones at a baseline normal so um this is kind of like a fail-safe you can think about it so this is kind of what happens in a normal pregnancy right if your thyroid is working right you’re making more t3 t4 for your baby and the mom but you’re also making sure that there’s not too much all right you’re making tbg

With the estrogen to make sure there’s a buffer going on but if your thyroid at a baseline is not working you have primary hypothyroidism then let’s think about it you’re making beta hcg and it’s really trying to stimulate your thyroid but in primary hypothyroidism your thyroid is at a baseline dysfunctional so no matter if you’re stimulating your tsh or beta

Hcg you’re not really making adequate amount of t3 and t4 so you have low amounts of t3 t4 now you’re still going to have estrogen going on if you’re pregnant and having primary thyroid dysfunction with estrogen you’re going to increase your tbg your thyroid beta globulin in your blood this is going to bind whatever little amount of thyroid you’re even making

And overall your thyroid hormones are going to go down and you’re going to feel very low energy your baby’s not going to get enough energy so this is why because you’re taking exogenous thyroid hormone that levothyroxine you do need to increase it by up to 30 and the guidelines state when you become pregnant immediately increase it up to 30 and every four weeks

Have a recheck with your pcp to make sure your thyroid hormones and thyroid levels are adequate for you and your baby and we adjust it accordingly so that in a nutshell is hypothyroidism and how you treat it by increasing levothyroxine by 30 in pregnancy

Transcribed from video
Why you need to increase Levothyroxine in Pregnancy By Atif Hussain