Antithyroidal Antibodies With or Without Subclinical Hypothyroidism During Pregnancy in Infertile Women
Condition: Thyroid Gland Disease; Pregnancy Complications
MeSH terms: Pregnancy Complications; Thyroid Diseases
Study type: Observational

Summary: 
      One prospective observational study was carried out in 2009 aiming at identifying the
      fluctuations of the thyroid hormones in women with normal thyroid gland and in women with
      anti-TPO antibodies. Serum samples were collected periodically during and after pregnancy in
      previously infertile women. The samples were stored frozen at -80 °C. Now, the hormone
      measurements will be carried out.
    

Detailed description: 
      Exclusion of thyroid disease has long been an integral part of a comprehensive infertility
      work-up, because thyroid function disorders are also associated with disturbances in the
      menstrual cycle and can cause complications during pregnancy. Subclinical hypothyroidism is
      the most frequent disease of the thyroid in women of reproductive age (affecting 5 to 10 %).
      For a long time, measurement of TSH concentration was the only screening parameter used to
      exclude thyroid disorders. Not only has the differentiation of normal thyroid function
      (euthyroidism) from the pathological range been controversial for some years but, recently,
      the role of an elevated anti-TPO antibody titre has also been identified as a significant and
      independent risk factor for miscarriages and for complications during late pregnancy, even in
      otherwise euthyroid women. This discovery implies that solely determining the TSH
      concentration is insufficient. The mechanism underlying the increased rate of complications
      during pregnancy is also unclear.

      The investigators therefore performed a double study to clarify the relative importance of
      the various possible parameters of thyroid function in the context of an infertility work-up:

        1. Prevalence study: Measurement of TSH and anti-TPO concentrations in 175 women who
           present with infertility at the Infertility Clinic at the Women's Hospital, University
           Hospital Basel. In addition, each participant underwent an ultrasound scan of the
           thyroid. Control group: 175 healthy women of reproductive age and with regular menstrual
           cycles, but not currently wishing to have children (recruited via posters in the
           university and Blood Donor Centre). This study has been finished in 2010. The data of
           the prevalence study were used to carry out the prospective sampling of the serum
           samples.

        2. Prospective measurement of fluctuations in thyroid function during pregnancy and
           post-partum in a group of euthyroid women and/or those with subclinical hypothyroidism
           (TSH > 4.5 mIU/l) with/without anti-TPO antibodies. Two different euthyroid groups were
           defined for the study: Euthyroidism I = TSH 0.3-2.5 mIU/l; Euthyroidism II = TSH 2.5-4.5
           mIU/l. Six groups, each with 16 women, divided according to TSH concentration and
           anti-TPO antibody status, will be required (total 96). All female participants with
           subclinical hypothyroidism (TSH concentration > 4.5 mIU/l, normal values of peripheral
           thyroid hormones) receive a T4 supplementation dose. Serum samples will be collected
           each week from the start of pregnancy up to the 12th week and stored frozen at -80 °C.
           Thereafter, a serum sample will be collected once a month (up to the 38th week) and
           stored frozen at -80 °C. Finally, one serum sample post-partum (4 to 6 weeks after
           delivery) and freeze it. A total of 96 women (16 in each group) were recruited to
           participate in this study.

      After conclusion of the observation period, levels of the following hormones will be measured
      in the total of 1120 serum samples: TSH, total and free l-thyroxine and fT4 index, total and
      free triiodothyronine, thyroid autoantibodies (TPO antibodies), hCG, 17β-oestradiol,
      progesterone, prolactin.
    

Intervention name(s): serum sampling
Intervention type(s): Other
Intervention description(s): repeated serum sampling during pregnancy and thereafter
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Healthy women having become pregnancy after infertility.
      
Biospecimen description: 
      Serum samples
    
Keywords: thyroid; antibody; pregnancy; infertility