Association of TSH level above 2.1 mlU/L and first trimester pregnancy loss in anti-TPO antibody negative women

Although the exact level of TSH that is indicative of risk of pregnancy loss is not known, a number of studies have suggested a range of values for TSH level that are associated with first trimester pregnancy loss. We conducted an unmatched case-control study to test if a TSH level above 2.1 mlU/L is associated with first trimester pregnancy loss in anti-TPO antibody negative women. We found relatively higher number of women in the case group (18) whose TSH level was above 2.1 mlU/L compared to 7 women in control group. When considered patients in Group I (TSH [≤] 2.1 mlU/L), 45.74% had miscarriage while 54.26% did not have miscarriage within first trimester of pregnancy. Among the Group II patients (TSH > 2.1 mlU/L), 78% had miscarriage and 28% did not have miscarriage. Noticeably there is a larger proportion of miscarriage among the women with TSH level above 2.1 mlU/L. The association between TSH level and first trimester pregnancy loss was statistically significant (p=.0196). From the multivariate analysis, odds ratio for TSH level (OR 4.0, 95% CI: 1.44-11.16) indicates that odds of having miscarriage whose TSH level is above 2.1 mlU/L is 4 times compared to those with TSH level below 2.1 mlU/L after adjusting for the effects of age and BMI. At a global level, the findings of this study provide evidence to the existing discussion on redefining the upper limit of TSH level that is related to first trimester pregnancy loss. At the local level, the results will have direct implication in facilitating management of future pregnancies particularly during the first trimester among Bangladeshi thyroid autoantibody negative women. (268 words)