Abstract:  Objective Toestablishthegestationalmonth-specificstage ( firsttrimesterof
pregnancy , secondtrimesterofpregnancy , thethirdtrimesterofpregnancy ) referenceintervals
formaternalthyroidfunctionintheareaofShijiazhuangGaoxinarea.Methods Atotalof120
pregnantwomenand60non-pregnantwomenwereselectedaccordingtothestrictcriteria.The
studymeasuredmaternalthyroidfunction.Thenormalreferenceintervalsofpregnancyspecific
serumfreetriiodothyronine ( FT 3 ), freethyroxine ( FT 4 ), thyroidstimulatinghormone ( TSH )
wereestablished.Results Serum FT 3 , FT 4 , TSHlevelswerequitedifferentbetweennon-
pregnantwomenandpregnantwomen ( P <0.01 ) .Comparingwiththereferenceintervalsfor
maternalthyroidfunctionlevelofnon-pregnantwomen , theserumFT 4 wassignificantlyhigher
andTSH waslowerinthe1sttrimesterofpregnancy ( P <0.05 ); theserumlevelofFT 3 and higherinthe2ndtrimesterofpregnancyand3rdtrimesterofpregnancy ( P <0.05 ) .Comparing
withthereferenceintervalsformaternalthyroidfunctionof2ndtrimesterofpregnancy , the
serum FT 4 waslowerand TSH washigherinthe3rdtrimesterofpregnancy ( P <0.05 ) .
Conclusion Referenceintervalsforthyroidfunction werequitedifferentbetween pregnant
womenandnon-pregnantwomen , anditwasquitedifferentindifferenttrimestersofpregnancy.
TSH werelowerinthe2sttrimesterofpregnancy ( P <0.05 ); theserumFT 3 andFT 4 werelower
inthe3sttrimesterofpregnancy ( P <0.05 ) .Comparingwiththereferenceintervalsformaternal
thyroidfunctionof1sttrimesterofpregnancy , theserumFT 3 andFT 4 werelowerandTSH was

Key words:  pregnancy , thyroidfunctiontests , referencevalues