P-693 IVF outcome in patients with thyroid disease
Authors: Korosec S , Franko Rutar A , Paljk Likar I 
Published: June 2022

Abstract

Study question
What is the thyroid disease rate in IVF patients and how does it affect their IVF outcome?

Summary answer
The thyroid disease rate was 19,5%, mostly of inflammatory origin. IVF outcome in these patients was similar to controls, but coexisting endometriosis rate was higher.

What is known already
Thyroid disease is the most common endocrine disorder in females of reproductive age. It is estimated that 20% of infertile females has history of thyroid disease. Thyroid hormones importantly impact fertility, acting directly on oocytes, sperm and embryo during fertilization, implantation and placentation, regulating estrogen and androgen metabolism as well as the menstrual cycle. The most common causes of thyroid disfunction are autoimmune disorders. The prevalence of thyroid autoimmunity among women undergoing IVF treatment is higher compared to the general population. Women with thyroid autoimmunity have higher risk of miscarriage, preterm birth and it may impact the IVF-ET outcome.

Study design, size, duration
It was a single center trial at the Division of Obstetrics and Gynecology, Department of Human Reproduction in the University Medical Centre of Ljubljana, Slovenia. The study included women undergoing their first IVF treatment in a one-year period.

Participants/materials, setting, methods
A total of 226 women undergoing their first IVF treatment were included. In the first part of our study, Patient characteristics and IVF outcome according to different TSH serum levels (&lt; 0,59 mE/L, 0,59 - 2,5 mE/L, 2,5 - 4,23 mE/L ter &gt; 4,23 mE/L) were analysed. In the second part of the study, we compared patient characteristics and IVF outcome in patients with and without thyroid disease.

Main results and the role of chance
The average age was 33 ± 4,7 years, the average BMI was 24±4,9 kg/m2. Three percent of women had TSH levels &lt;0,59 mE/L, 74% had TSH levels 0,59-2,5 mE/L,18% had TSH levels 2,5-4,23 mE/L and 6% had TSH levels &gt;4,23 mE/L. The obesity rate (BMI&gt;30 kg/m2) was significantly different in all four groups of patients with the highest rate in the group of TSH 2,5-4,23 mE/L.
Thyroid disease was found in 19,5% of patients (thyroid autoimmunity 18%, Hashimoto's thyroiditis 7,5% of patients). The thyroid disease rate was significantly different in all four groups with highest rate in group having TSH &gt;4,23 mE/L and the lowest rate in group having TSH 0,59-2,5 mE/L.
Endometriosis was diagnosed in 22% of patients with highest rate in patients having highest TSH levels.
There was no correlation between patient characteristics and reproductive history (age, irregular menstrual cycle, dysmenorrhea, pregnancy, spontaneous abortion, recurrent abortion, FSH and LH serum levels) and TSH levels or preexisting thyroid disease. There were no significant differences in the IVF outcome (numbers of retrieved oocytes, immature oocytes and number of embryos) according to TSH levels or preexisting thyroid disease. Thyroid disease rate was significantly higher in patients with endometriosis.

Limitations, reasons for caution
Our study limitation is a smaller sample size that may affect our results, specifically the differences in the IVF outcome. There was no statistical difference in miscarriage and recurrent miscarriage rate in women with thyroid disease and women with normal thyroid function.

Wider implications of the findings
Our study gives an insight to the characteristics of women with thyroid disease undergoing IVF treatment in our facility, although the differences were statistically insignificant. As a secondary outcome we discovered a statistically significant correlation of endometriosis and inflammatory thyroid disease, which is rarely mentioed in the literature.

Trial registration number
not applicable