iThei mdcdaelcinfd o c elllllrllll cf tthfeautoimmune thyroid after giving birth; 80 percent of those women
spontaneously regain normal thyroid function, but 20 percent go on to
develop Hashimoto’s.
During pregnancy, fetal thyroid cells can get into maternal thyroid cells.
In some cases, these fetal cells can be found in the maternal thyroid for
many years after the baby is born. There is a new theory that if the fetal
cells persist after birth, this causes a graft-versus-host response. Since the
immune system is no longer suppressed by pregnancy Tregs, it begins to
recognize the fetal cells as foreign. This theory is still hypothetical, how-
ever, and has not been confirmed.
An alternate, more likely possibility is that nutrient depletions that occur
during pregnancy trigger thyroid inflammation. It is widely known that
nutrient requirements increase during pregnancy, and pregnant women are
advised to take prenatal vitamins. Women with TPO antibodies who sup-
plemented 200 mcg selenium during pregnancy were found to have lower
TPO antibodies during pregnancy and after giving birth as compared with
those who did not take selenium.
Additionally, only 28.6 percent of the selenium group developed post-
partum thyroiditis as compared with 48.6 percent of the group that did
not take selenium.
Ultrasound monitoring showed the thyroid appearance remained sta-
ble in the selenium group, while the group that did not take selenium
showed thyroid tissue destruction on ultrasound.
Ideally, women should try to uncover their triggers before becoming
pregnant, although this is not always realistic. Immune modulation is
contraindicated during pregnancy, but adequate nutrition and perhaps
selenium supplementation may improve outcomes. Thyroid hormone
requirements also go up during pregnancy, thus close monitoring of thy-
roid function is recommended for those with Hashimoto’s.
Oral Contraceptives
In addition to pregnancy, oral contraceptives (which produce a sort of
“pseudo-pregnancy” due to the mix of hormones taken) stimulate a shift
from Th1 to Th2. Similar changes in immune function may appear after
stopping or starting oral contraceptives. As discussed in the Depletions
chapter, oral contraceptives may cause depletions in our own endogenous
hormones as well as in vitamins, minerals, and beneficial bacteria.