Levothyroxine and messed up period: Hello, My... - Thyroid UK

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Levothyroxine and messed up period



My periods were regular (28 days), I was ovulating but because I couldn't get pregnant, I went to a fertility specialist and shortly after found out that I have hypothyroidism (TSH 10.10 and antibodies found). The doctor put me on 25mcg because I had bad side effects with TEVA 50mcg. After 8 weeks I did a blood test which showed that my TSH was normal (2.5) and all the vitamins were ok. I asked my doctor if I should go on 50mcg to lower TSH (it's apparently good to have TSH of 2 or lower if you're trying to conceive) and increase the chances of getting pregnant. Because of the bad side effects, he suggested for me to take 50mcg levothyroxine on Mondays and Thursdays (2 per week) and 25mcg on all the other days.

Now, my period shortened a lot (from 28 to 23 days), which never happened before and I got a lot of spots on my face which clearly shows a hormonal imbalance.

Did anyone else have the same experience (periods messed up after started taking levothyroxine)? Do you know if it can stabilize in the near future?

Thank you for your help!

4 Replies


Thyroid hormone levels can affect the metabolism of female sex hormones and interfere with the regulation of ovarian function ..... either to do with oestrogens and progesterone fluctuations, or imbalanced cortisol levels, or to do with the sex hormone binding proteins grabbing hormone and disabling it from becoming active.

The HPA-Axis and HPT-Axis work in parallel and cortisol and TSH should correlate. All hormones are dependant on each other so any deficiency (or elevation) may have repercussions somewhere up the line.

Low thyroid hormone encourages more TSH (thyroid stimulating hormone) and TRH (thyrotropin releasing hormone) to be secreted but by doing this the body also creates prolactin which interferes with ovulation. Low thyroid hormone can also influence the luteal phase (time between ovulation and menstruation usually between 13 and 15 days).

Luteal phase issues can be due to too much oestrogen which will encourage elevated SHBG that can bind thyroid hormone making it unavailable for use. Elevated oestrogen can also interfere with development of follicles and good FSH & LH surges needed for ovulation.

You have Hashimotos and elevated thyroid antibodies can influence the development of immune cells and modulate the output of the immune system. Many immune cells have receptors for these sex hormones that also activate some of specific genes that play a role in symptom flares. That is why many members find they become more Hashi symptomatic around their period time.

Your side effects indicate your body is still acclimatising to the new introduced hormone and you may still have nutritional deficiencies. It is important to achieve a low TSH when trying to conceive to avoid possible pregnancy complications but getting thyroid hormone replacement to work usually takes optimal levels of iron, nutrients, adequate cortisol levels and managed thyroid antibodies.

If you are supplementing folic acid, given that you have Hashimotos it is better to supplement Methylfolate that is are readily absorbed & utilised.

Flowerflower in reply to radd

Thank you radd, all my vitamins, ferritin and folate levels are good. I hope the body will acclimatise soon!


Many, many people react very badly to Teva

Get a new prescription for different brand of 50mcg Levothyroxine.

What is the brand of 25mcg ?

As you have raised antibodies this is Hashimoto's

About 90% of all primary hypothyroidism in Uk is due to Hashimoto's

Essential to test vitamin D, folate, ferritin and B12.

Can you Post results and ranges, members can advise

These need to be optimal, not just within range, especially before TTC

Hashimoto's affects the gut and leads to low stomach acid and then low vitamin levels

Low vitamin levels affect Thyroid hormone working

Poor gut function can lead leaky gut (literally holes in gut wall) this can cause food intolerances. Most common by far is gluten.

According to Izabella Wentz the Thyroid Pharmacist approx 5% with Hashimoto's are coeliac, but over 80% find gluten free diet helps, sometimes significantly. Either due to direct gluten intolerance (no test available) or due to leaky gut and gluten causing molecular mimicry (see Amy Myers link)

Changing to a strictly gluten free diet may help reduce symptoms, help gut heal and slowly lower TPO antibodies

Ideally ask GP for coeliac blood test first






The brand I'm currently taking is Wockhardt (I had really bad side effects from TEVA ). The only side effect I have now is shortness of breath. Do you know any brands that are more appropriate for people that are very sensitive to hormonal changes?

The thing is that my TSH dropped from 10.10 to 2.5 within a months after started taking 25mcg of levo (which is a super low dose). I then spoke to my endo and said that I should probably on TSH 2.0 or lower if trying to conceive so he put me on 50mcg every Monday and Thursday as he thinks I'm sensitive to hormonal changes.

The problem is that before my dose was increased, I was feeling fine on 25mcg and my period was regular. Now, my period got totally messed up which doesn't help as I'm trying for a baby... Do you think I should go back to 25mcg? Also, I've been changing my dose quite a lot and I'm not sure that's good for my body either...

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