Postpartum Thyroiditis: Why Doesn't Your Fatigue Improve With Sleep?
Feeling cold when others don't, or a tiredness that doesn't get better with sleep, may not be due only to lack of sleep after giving birth. It could be postpartum thyroiditis, a common condition that isn't routinely screened for and that can be detected with a blood test.
What postpartum thyroiditis is
It is an inflammation of the thyroid that appears in the first year after giving birth. According to the American Thyroid Association, between five and ten in every hundred women develop it during that period.
It is not routinely screened for, so it has to be suspected. The thyroid, located in the neck, sets the body's pace: how much heat you produce, how fast your heart beats and how quickly you think.
Why it appears right after giving birth
The explanation lies in pregnancy. For nine months, the immune system tones itself down to tolerate a fetus with half of its genes coming from someone else.
After birth, that truce ends. In some women, the rebound in the immune defences turns against their own thyroid.
First phase: between the first and fourth month
The thyroid works like a storehouse full of hormone. When the immune defences damage it, that reserve spills into the bloodstream all at once.
In this phase the heart may race. Sleeping is difficult even when the baby is asleep. Irritability appears and weight drops quickly. It is easy to mistake this for postpartum nerves or for losing the weight gained during pregnancy.
Guidelines advise against antithyroid drugs in this phase. The gland is not producing too much hormone: it is emptying out.
Second phase: between the fourth and eighth month
Afterwards, the storehouse is left empty and the opposite phase begins. The symptoms are feeling cold, tiredness that doesn't improve with sleep, constipation, dry skin, brain fog and sadness.
Only one in four women goes through both phases. The most common form begins directly with the cold phase.
How it is diagnosed
It is distinguished from the normal tiredness of caring for a baby with a blood test that measures TSH and free thyroxine. TSH is the signal the brain sends to the thyroid.
In the accelerated phase, TSH comes back low. In the cold phase it comes back high, because the brain keeps insisting. Anti-TPO antibodies help confirm the cause of the problem.
Who is at higher risk and when to ask for the test
The risk is higher if anti-TPO antibodies were present at the start of pregnancy, if there is type 1 diabetes, or if thyroiditis occurred after a previous birth, because it tends to recur.
It is worth asking for the test if your tiredness gets worse over the months, if you feel cold when others don't, or if you notice palpitations at rest or a more swollen neck.
The same applies if there are symptoms of postpartum depression. Endocrinology guidelines recommend checking the thyroid, while still treating the depression. If thoughts of harming yourself or the baby appear, do not wait for any test: go to the emergency department.
Frequently asked questions
If my thyroid was fine during pregnancy, can I rule out postpartum thyroiditis?
No. This condition begins after birth, when pregnancy check-ups have already ended.
Does breastfeeding prevent treatment of postpartum thyroiditis?
No. Levothyroxine, when needed, is considered compatible with breastfeeding, because it is a copy of the hormone the mother already produces.
Does postpartum thyroiditis go away on its own?
The thyroid usually recovers within about a year. However, between one in five and half of women develop permanent hypothyroidism years later, which is why guidelines recommend a yearly blood test.
Can it come back in another pregnancy?
Yes. Having had thyroiditis after a previous birth increases the risk, because it tends to recur.
Informative article written with the help of AI tools from the verified script of the video. The video is in Spanish.