Thyroid medication under and over active and Breastfeeding The task force cautions against the use of excessive iodine (from sources such as seaweed snacks or high-dose supplements) during pregnancy and while breastfeeding, as this can lead to hypothyroidism in the fetus or infant. Hyperthyroidism in newborns is often caused by TRAb from the mother crossing the placenta during pregnancy. This issue is treated with ATDs and usually resolves within 1-3 months. Due to the increased risk of liver issues with PTU (a rare, but very serious occurrence), methimazole is the preferred drug. Since hypothyroidism can cause low milk production, it can be challenging to breastfeed your baby. When the thyroid is not functioning correctly, it can impact milk production. The half-life of MMI is 4–6 h, while PTU has a half-life of about 75 min 8. PTU is about 80% protein bound, while MMI is non-protein bound and more lipid soluble 7. Women who are being treated for Graves’ disease are advised to postpone pregnancy planning until thyroid function is stabilized, as indicated by two normal tests at least one month apart, with no change in medication dosing. Thyroid medications The timing of this procedure (during pregnancy or after delivery) can be influenced by the risk of malignancy as well as patient preference. For women with a history of Graves’ disease, the postpartum period comes with a high risk of relapse or of increasing severity of disease. A study out of Japan has indicated that low-dose ATD therapy following delivery might reduce the risk of relapse, although further studies are needed in this area. The postpartum period is also a high risk time for new development of Graves’ disease. Trimester-specific ranges for thyroid function testing are recommended during pregnancy, due to typical increases of T4 and suppression of TSH in the first trimester. Variations that occur due to race, ethnicity, iodine intake, the presence or absence of thyroid antibodies, and even body mass index can make development of these ranges challenging. The guidelines were dedicated to Dr. Peter Laurberg, an internationally recognized thyroidologist and a member of the task force, who sadly passed away in 2016. It’s a bit scary to think of (at least it was for me!), but it doesn’t really hurt at all (about like synthroid conceiving having blood drawn from your arm) and it just takes a few minutes. I’ve had 2 fine needle biopsies and the second was so much easier since I know what to expect. Buy The Real Thyroid In this case, antithyroid drugs (ATD) are considered the treatment of choice by most endocrinologists for Graves’ hyperthyroidism (GH). Although the guidelines state that iodine deficiency is generally not a concern in the U.S., “U.S. The guidelines note that women who are pregnant or breastfeeding should ingest 250 micrograms of iodine daily. (One exception is that women currently being treated with thyroid hormone replacement do not require supplemental iodine). The guidelines note that women who were diagnosed with hypothyroidism prior to pregnancy and increased their dose of thyroid hormone replacement should resume their pre-pregnancy dose following delivery, with follow-up testing recommended six weeks later. Mothers who have the autoimmune forms of thyroid disease will usually have thyroid autoantibodies present in their blood. Pregnancy and thyroid disorders – guidance for patients Symptoms are initially controlled by anti-thyroid drugs (carbimazole or propylthiouracil) and beta blockers. In some cases, the gland is removed surgically or by the use of radioactive iodine and levels replaced by synthetic levothyroxine. A mother with an under active thyroid needs to take medication to return her blood levels to “normal”. It is worth repeating blood levels after delivery as anecdotally, fluctuations seem common at this time. Thus, you’ll have a normal range of thyroid levels, which is important for normal lactation and maintaining a sufficient supply of milk. To test postpartum thyroiditis, doctors may use radioactive iodine, which isn’t safe for pregnant and breastfeeding women. Therefore, make sure to let your doctor know and ask them when it’s safe to resume breastfeeding after a test. This scan is done using radioactive iodine (I-131), and is usually done at the same time as a thyroid scan. Technetium-99m has a very short half-life (6.02 hours, compared to 8.1 days for I-131). For infants with congenital hypothyroidism, thyroid hormone replacement is required. For babies born with hypothyroidism due to the mother taking ATDs during pregnancy, the drugs typically clear the infant’s system quickly, with thyroid function being restored to normal. Adequate thyroid hormone serum levels are required for normal lactation. Replacing deficient thyroid levels should improve milk production caused by hypothyroidism. Supraphysiologic doses would not be expected to further improve lactation. Thyroid Levels and Effects while Breastfeeding Studies during breastfeeding have found no adverse reactions in breastfed infants clearly attributable to propranolol (Lactmed). The amount of time suggested for suspending breastfeeding varies depending on the dosage and form of the isotope (there are many forms of Tc-99m). The type of thyroid scan I had was a radioactive iodine uptake & thyroid scan. For infants with congenital hypothyroidism, thyroid hormone replacement is required. Symptoms of an under active thyroid include gain in body weight, dry skin and hair and tiredness. However, this approach may be used in rare cases where the mother is hypothyroid after RAI or surgery, but maternal antibodies are causing hyperthyroidism in the fetus. Women who are being treated for Graves’ disease are advised to postpone pregnancy planning until thyroid function is stabilized, as indicated by two normal tests at least one month apart, with no change in medication dosing. The guidelines note that, “Women with GD seeking future pregnancy should be counseled regarding the complexity of disease management during future gestation, including the association of birth defects with antithyroid drug (ATD) use. Preconception counseling should review the risks and benefits of all treatment options and the patient’s desired timeline to conception.” These treatment options include antithyroid medications, radioactive iodine, and thyroidectomy. The US Food and Drug Administration followed with the same
