Anti-thyroid antibodies and miscarriage
Women with anti-thyroid antibodies and a normally functioning thyroid gland may be at greater risk for miscarriage. Some studies looked at women with recurrent miscarriage and found that they have higher levels of anti-thyroid antibodies compared to women without recurrent miscarriage. Some studies did not find an association. One publication combined the results of 18 studies on this topic (meta-analysis) and concluded that there is an ASSOCIATION between the presence of elevated anti-thyroid antibodies and miscarriage. One of the most recent studies on the topic, which has also been one of the largest, again showed a correlation between thyroid antibodies and miscarriage.
There are several explanations for why there may be an association between anti-thyroid antibodies and miscarriage.
# Link with other autoimmune problems.
It is possible that women with elevated levels of anti-thyroid antibodies may have other immune problems and these other problems may be responsible for miscarriage. It is well accepted, for example, that another type of immune problem involving anti-phospholipid antibodies can cause miscarriage. Some of the studies did try to control for this problem by excluding women who had abnormal levels of other known antibodies but there still may be immune issues that they did not control for.
# Direct involvement of the antibodies.
A commonly asked question is why antibodies against the thyroid gland would cause a problem elsewhere. It may be possible that the anti-thyroid antibodies may “get confused” or “cross react” and therefore also attack placental or fetal tissues. If this hypothesis were true, we should see a “dose-response relationship” That is, we would expect higher levels of anti-thyroid antibodies in women who actually miscarried compared to those who had a full term delivery. Most studies did not look at this. Two studies did not find a dose response relationship and one did.
# Effect of age
In most of the studies analyzed, women with elevated levels tended to be older as a group compared to those women with normal antibody levels. Since the miscarriage risk for women increases with age, this could be an explanation.
Iz gornjeg teksta, posebno mi je interesantan sledeci podatak: At mogu da se "zbune" odnosno da ukrsteno reaguju sa placentalnim ili fetalnim tkivom. U slucaju da je ova pretpostavka tacna, mora postojati dozno-zavisni efekat, tj sto je veci titar At, veca je mogucnost za pobacaj.
Treatment of anti-thyroid antibody related miscarriage
Very well designed trials indicate that selenium supplementation may reduce the levels of some types of anti-thyroid antibodies. It is possible that if the levels of the antibodies can be reduced, then the risk of miscarriage may also be reduced
The effects of selenium in pregnancy were recently evaluated in a study performed in Italy. Approximately 150 pregnant with with elevated levels of one group of thyroid antibodies were split into two equal groups. One group received 200 micrograms of selenium and the other group received placebo. During pregnancy and post-partum, more women who took the placebo were more likely to show evidence of thyroid malfunction and need thyroid hormone supplementation.
A evo i jednog teksta, vadim samo zakljucak, koji kaze da kod zena pozitivnih na ove dve vrste At nema problema u smislu vantelesne oplodnje, ali i u tim slucajevima moze doci do pobacaja.
The study findings were as follows :
# The pregnancy rate with IVF was similar in all groups. In other words, the presence of anti-thyroid antibodies did not influence the chances for success and using thyroid hormone did not improve the chances for success.
# The miscarriage rate with IVF was higher in women who had anti-thyroid antibodies. Using thyroid hormone for treatment did not reduce the risk for miscarriage.