[Clinical analysis of hypothyroidism during pregnancy]

To investigate the incidence, treatment and pregnant outcomes of women with hypothyroidism during pregnancy.

A retrospective analysis was conducted on the perinatal care, treatment and pregnant outcomes of 31 pregnant women with hypothyroidism from Jan.1995 to May.2006 in our hospital. All subjects were received in the high risk clinic, and the thyroid function was monitored every 1.0 - 1.5 months. The dosage of LT4 was adjusted to maintain the normal level of thyroid function.

The incidence of maternal hypothyroidism during the study period was 1.27 per thousand (31/24 327) [0.19 per thousand (1/5251) - 2.32 per thousand (15/6456)]. The average LT4 dosage in pre-gestation, the first, second, third trimester and postpartum was (33 +/- 35), (51 +/- 36), (68 +/- 42), (76 +/- 42) and (38 +/- 34) microg/d, respectively. Compared with the pre-gestational period, the dosage in the first trimester or postpartum was higher although the difference was not significant (P>0.05). The required dose of LT4 during the second and third trimester was respectively, remarkably increased compared to pre-gestational period (P<0.05). The average increase of the dose of LT4 required during the pregnancies was about 35%. All of 31 women had uneventful pregnancies. No perinatal mortality or congenital hypothyroidism occurred. The incidence of abnormal glucose metabolism was up to 16.1%.

The incidence of maternal hypothyroidism is increasing yearly. It is of great value in improving the pregnant outcome through adjusting the LT4 dose during pregnancy and close monitoring of maternal and fetal status.