Postpartum Thyroid Troubles

After having your baby, your thyroid naturally goes through another period of adjustment. Approximately 10 percent of all women will have some sort of postpartum thyroid problem, including the onset of an autoimmune thyroid disease or postpartum thyroiditis.

During this time, the immune system is readjusting and returning to its normal state. As you probably recall, the immune system is suppressed during pregnancy to ensure that the mother's body doesn't reject the fetal tissue. In the postpartum period, this process reverses itself, and the immune system gradually resumes normal activity.

As a result, women who have Hashimoto's or Graves' disease may notice a resurgence of their symptoms or show a change in their TSH levels. Those who had increased their dose of levothyroxine for Hashimoto's disease, for instance, can often go back to their lower prepregnancy dose. Women with Graves' disease may notice a worsening of symptoms and need to increase their dose of antithyroid medication.

The postpartum period is also ripe for the onset of an autoimmune disease, such as Hashimoto's or Graves' disease. Women who develop these conditions after delivering a baby will undergo the same diagnostic tests and have the same treatment options as anyone else. For more information, see Chapters 6 and 9. But women who are nursing should not be given radioactive iodine treatments.

Postpartum Thyroiditis

Many women go through a difficult time after having their babies. They're tired from nightly awakenings and feedings. They may have mood swings and bouts of unexplained sadness and crying. They may also have anxiety, insomnia, and fatigue — all common to new moms.

But for some women, the symptoms are related to a condition called postpartum thyroiditis, in which the thyroid gland becomes inflamed. Women with a personal or family history of autoimmune disease are at higher risk for postpartum thyroiditis, as are those whose mothers had this condition.


In rare circumstances, severe blood loss during childbirth can cause a condition called Sheehan's syndrome, or postpartum hypopituitarism. The condition causes a reduction in hormones produced by the pituitary, including TSH, and can lead to hypothyroidism. In Sheehan's syndrome, you may also have a sudden drop in the stress hormone, cortisol, which can produce an adrenal emergency.

Postpartum thyroiditis often lasts six to nine months, then disappears on its own. In most cases, the condition begins two to three months after delivery and follows a similar pattern. The thyroid is initially overactive for a month or two, when the inflamed gland starts leaking excess thyroid hormone into the bloodstream. After that, as the hormone dissipates, it becomes underactive for a few months, before becoming normal again. The condition is diagnosed with a TSH test and the patient's self-reported symptoms.

It isn't always easy to detect postpartum thyroiditis. Most women attribute the symptoms to the normal exhaustion that comes with tending to a new baby and to the natural shifts in hormone. But some experts suspect that postpartum thyroiditis is the culprit behind postpartum depression, a condition in which women become clinically depressed after giving birth. That would make postpartum thyroiditis considerably more common than believed.

As with most thyroid disease, the severity of postpartum thyroiditis can vary widely. In some cases, the symptoms are mild and barely even noticed, in which case treatment is a matter of waiting it out. But in other cases, the symptoms may be more pronounced. You may feel anxious and nervous, and you may have trouble breathing. Or you may feel overly tired, sluggish, and depressed.

Women who do have more disturbing symptoms might be prescribed beta-blockers to tame their hyperthyroidism. They may also require an antithyroid medication such as PTU (see below about nursing considerations). If the condition is detected in its hypothyroid stage, you may be given thyroid hormone replacement. Some women with postpartum thyroiditis go on to develop permanent hypothyroidism.

In any case, if you do develop postpartum thyroiditis, be on the lookout for future thyroid problems. Women who have postpartum thyroiditis are more likely to develop thyroid disease, and are more likely to have postpartum thyroiditis with future pregnancies.

Nursing Concerns

Breastfed babies reap many benefits from their moms, and it goes well beyond the vitamins and minerals found in breast milk. Nursing infants also get brain-enhancing fatty acids and immune system boosters that can protect them from illness. And according to the American Academy of Pediatrics, babies who are breastfed exclusively for six months are less likely to have ear infections, respiratory illnesses, and diarrhea.


Breastfeeding moms may benefit from nursing their babies, too. Studies show that women who breastfeed may have a lower risk of breast and ovarian cancer, and a decreased risk of hip fractures and osteoporosis.

But nursing moms with thyroid disease may wonder whether the drugs they take will affect their babies, too. The answer depends largely on the medicine you need, but also on the amount you take and whom you ask.

If you have hypothyroidism, thyroid hormone replacement drugs are generally fine, so long as you're on the correct dosage. Only small amounts of these drugs get into the breast milk. Too much thyroid hormone, on the other hand, can affect the baby, who is then at risk for hyperthyroidism, just as you are. So if you are taking thyroid hormones, you'll need routine TSH tests to make sure you're getting just the right dosage.

Treatments for hyperthyroidism are much more controversial. For starters, you cannot receive RAI treatments or undergo RAI scans if you are nursing. The RAI collects in breast milk and can be transferred to the baby, whose thyroid gland would take up the iodine. If you absolutely need to have RAI treatment — the Graves' disease has become severe, for instance — you'll be asked to stop nursing or told to delay the RAI until you're finished nursing.

For nursing moms, antithyroid drugs are usually a better choice. PTU is generally the preferred treatment because less of it seeps into breast milk than methimazole. Taking as low a dose as possible is best, if you nurse. One study done in Japan found that women can safely take PTU while breastfeeding, so long as the dose is 750 mg or less per day.

Nonetheless, doctors worry about the impact of PTU on nursing infants. According to a study in the journal Pediatrics, 44 percent of endocrinologists discourage breastfeeding while taking PTU. In the end, the decision to nurse and the need for medication rests with you and your physician.

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