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CHICAGO – Levels of thyroid stimulating hormone were significantly higher in women with unexplained infertility than in a cohort whose partners had severe male factor infertility, though TSH levels still fell within the reference range.
For women with unexplained infertility, thyroid stimulating hormone (TSH) averaged 1.95 mIU/mL (95% confidence interval, 1.54-2.61), compared with 1.66 mIU/mL for the group of women with severe male factor infertility, such as severe oligospermia or azoospermia (95% CI, 1.25-2.17; P = .003).
“We found, very interestingly, that in the unexplained group, TSH was higher in those women, compared with women whose partners had severe male factor infertility,” suggesting that , the study’s first author, Lindsay T. Fourman, MD, said in an interview at the annual meeting of the Endocrine Society.
In terms of TSH levels, “clearly, the cutoff of the upper limit of the normal range is controversial,” said Dr. Fourman. “Some studies have shown that 95% of the population has a TSH of less than 2.5.”
However, the numbers that guide treatment for hypothyroidism are different. “We use a cutoff, generally, of 4 or 5, but maybe that cutoff should be 2.5, and maybe that’s significant for some people,” Dr. Fourman said.
“Current guidelines do not recommend treatment of subclinical hypothyroidism among auto-antibody negative women attempting to conceive naturally,” wrote Dr. Fourman and her collaborators in the poster presenting their finding.
Twice as many women in the group with unexplained infertility had TSH levels in the upper half of the normal range – above 2.5 mIU/mL – than in the male factor infertility group, “again, suggesting this association with TSH and unexplained infertility,” Dr. Fourman said. The thyroid axis is known to play a role in oocyte development. Of women with unexplained infertility, 26.9% had a TSH above 5 mIU/mL, compared with 13.5% of those with severe male factor infertility (P less than .05).
The chart review of records from 187 women with unexplained fertility and 52 women whose partners had severe male factor infertility included women aged 18-39. The unexplained cohort included women for whom all causes of infertility were excluded “in the setting of a very thorough workup – and that would include any ovulatory issues, male factor issues, and by definition, these women had to have a normal FSH, TSH and prolactin,” said Dr. Fourman, an endocrine fellow at Massachusetts General Hospital, Boston.
Control patients were those who had TSH and prolactin levels available and whose partners were being seen for severe male factor infertility, meaning that their partner had severe oligospermia or azoospermia.
Dr. Fourman acknowledged that she and her and her collaborators couldn’t exclude some female factor infertility among the control group. “That is an assumption, but it’s an assumption that would bias us to the null,” strengthening the study’s findings.
Clinical characteristics were similar between study groups, though women with unexplained infertility were slightly older than those with severe male factor infertility (mean 31.5 years versus 30.1 years, P = .01); they also had slightly lower body mass indices (median 23 versus 24.4 kg/m2; P less than .04).
No association was found between prolactin levels, “which suggests that prolactin may not contribute to unexplained infertility in these women,” Dr. Fourman said.
The investigators were able to control for such potentially confounding variables as age, tobacco use, BMI; they excluded from analysis women who had positive thyroid peroxidase antibodies.
“This is very interesting, because it really raises the question of whether we should be treating TSH, even to the lower half of the normal range, to see if that can improve outcomes,” she said. “We are looking for modifiable things that we can treat to try to improve fertility, so if we can identify some cause – like a hormonal cause – we may be able to improve conception outcomes and reduce the need for invasive treatment.”
Based in part on the strength of these findings, Dr. Fourman said she and her collaborators are planning a prospective study to see whether treating women with infertility to achieve a TSH of less than 2.5 can speed time to conception and reduce the need for invasive infertility treatment.
Dr. Fourman reported no conflicts of interest and no external sources of funding.
SOURCE: Fourman, L, et al. ENDO 2018, Abstract SAT-288.
CHICAGO – Levels of thyroid stimulating hormone were significantly higher in women with unexplained infertility than in a cohort whose partners had severe male factor infertility, though TSH levels still fell within the reference range.
For women with unexplained infertility, thyroid stimulating hormone (TSH) averaged 1.95 mIU/mL (95% confidence interval, 1.54-2.61), compared with 1.66 mIU/mL for the group of women with severe male factor infertility, such as severe oligospermia or azoospermia (95% CI, 1.25-2.17; P = .003).
“We found, very interestingly, that in the unexplained group, TSH was higher in those women, compared with women whose partners had severe male factor infertility,” suggesting that , the study’s first author, Lindsay T. Fourman, MD, said in an interview at the annual meeting of the Endocrine Society.
In terms of TSH levels, “clearly, the cutoff of the upper limit of the normal range is controversial,” said Dr. Fourman. “Some studies have shown that 95% of the population has a TSH of less than 2.5.”
However, the numbers that guide treatment for hypothyroidism are different. “We use a cutoff, generally, of 4 or 5, but maybe that cutoff should be 2.5, and maybe that’s significant for some people,” Dr. Fourman said.
“Current guidelines do not recommend treatment of subclinical hypothyroidism among auto-antibody negative women attempting to conceive naturally,” wrote Dr. Fourman and her collaborators in the poster presenting their finding.
Twice as many women in the group with unexplained infertility had TSH levels in the upper half of the normal range – above 2.5 mIU/mL – than in the male factor infertility group, “again, suggesting this association with TSH and unexplained infertility,” Dr. Fourman said. The thyroid axis is known to play a role in oocyte development. Of women with unexplained infertility, 26.9% had a TSH above 5 mIU/mL, compared with 13.5% of those with severe male factor infertility (P less than .05).
The chart review of records from 187 women with unexplained fertility and 52 women whose partners had severe male factor infertility included women aged 18-39. The unexplained cohort included women for whom all causes of infertility were excluded “in the setting of a very thorough workup – and that would include any ovulatory issues, male factor issues, and by definition, these women had to have a normal FSH, TSH and prolactin,” said Dr. Fourman, an endocrine fellow at Massachusetts General Hospital, Boston.
Control patients were those who had TSH and prolactin levels available and whose partners were being seen for severe male factor infertility, meaning that their partner had severe oligospermia or azoospermia.
Dr. Fourman acknowledged that she and her and her collaborators couldn’t exclude some female factor infertility among the control group. “That is an assumption, but it’s an assumption that would bias us to the null,” strengthening the study’s findings.
Clinical characteristics were similar between study groups, though women with unexplained infertility were slightly older than those with severe male factor infertility (mean 31.5 years versus 30.1 years, P = .01); they also had slightly lower body mass indices (median 23 versus 24.4 kg/m2; P less than .04).
No association was found between prolactin levels, “which suggests that prolactin may not contribute to unexplained infertility in these women,” Dr. Fourman said.
The investigators were able to control for such potentially confounding variables as age, tobacco use, BMI; they excluded from analysis women who had positive thyroid peroxidase antibodies.
“This is very interesting, because it really raises the question of whether we should be treating TSH, even to the lower half of the normal range, to see if that can improve outcomes,” she said. “We are looking for modifiable things that we can treat to try to improve fertility, so if we can identify some cause – like a hormonal cause – we may be able to improve conception outcomes and reduce the need for invasive treatment.”
Based in part on the strength of these findings, Dr. Fourman said she and her collaborators are planning a prospective study to see whether treating women with infertility to achieve a TSH of less than 2.5 can speed time to conception and reduce the need for invasive infertility treatment.
Dr. Fourman reported no conflicts of interest and no external sources of funding.
SOURCE: Fourman, L, et al. ENDO 2018, Abstract SAT-288.
CHICAGO – Levels of thyroid stimulating hormone were significantly higher in women with unexplained infertility than in a cohort whose partners had severe male factor infertility, though TSH levels still fell within the reference range.
For women with unexplained infertility, thyroid stimulating hormone (TSH) averaged 1.95 mIU/mL (95% confidence interval, 1.54-2.61), compared with 1.66 mIU/mL for the group of women with severe male factor infertility, such as severe oligospermia or azoospermia (95% CI, 1.25-2.17; P = .003).
“We found, very interestingly, that in the unexplained group, TSH was higher in those women, compared with women whose partners had severe male factor infertility,” suggesting that , the study’s first author, Lindsay T. Fourman, MD, said in an interview at the annual meeting of the Endocrine Society.
In terms of TSH levels, “clearly, the cutoff of the upper limit of the normal range is controversial,” said Dr. Fourman. “Some studies have shown that 95% of the population has a TSH of less than 2.5.”
However, the numbers that guide treatment for hypothyroidism are different. “We use a cutoff, generally, of 4 or 5, but maybe that cutoff should be 2.5, and maybe that’s significant for some people,” Dr. Fourman said.
“Current guidelines do not recommend treatment of subclinical hypothyroidism among auto-antibody negative women attempting to conceive naturally,” wrote Dr. Fourman and her collaborators in the poster presenting their finding.
Twice as many women in the group with unexplained infertility had TSH levels in the upper half of the normal range – above 2.5 mIU/mL – than in the male factor infertility group, “again, suggesting this association with TSH and unexplained infertility,” Dr. Fourman said. The thyroid axis is known to play a role in oocyte development. Of women with unexplained infertility, 26.9% had a TSH above 5 mIU/mL, compared with 13.5% of those with severe male factor infertility (P less than .05).
The chart review of records from 187 women with unexplained fertility and 52 women whose partners had severe male factor infertility included women aged 18-39. The unexplained cohort included women for whom all causes of infertility were excluded “in the setting of a very thorough workup – and that would include any ovulatory issues, male factor issues, and by definition, these women had to have a normal FSH, TSH and prolactin,” said Dr. Fourman, an endocrine fellow at Massachusetts General Hospital, Boston.
Control patients were those who had TSH and prolactin levels available and whose partners were being seen for severe male factor infertility, meaning that their partner had severe oligospermia or azoospermia.
Dr. Fourman acknowledged that she and her and her collaborators couldn’t exclude some female factor infertility among the control group. “That is an assumption, but it’s an assumption that would bias us to the null,” strengthening the study’s findings.
Clinical characteristics were similar between study groups, though women with unexplained infertility were slightly older than those with severe male factor infertility (mean 31.5 years versus 30.1 years, P = .01); they also had slightly lower body mass indices (median 23 versus 24.4 kg/m2; P less than .04).
No association was found between prolactin levels, “which suggests that prolactin may not contribute to unexplained infertility in these women,” Dr. Fourman said.
The investigators were able to control for such potentially confounding variables as age, tobacco use, BMI; they excluded from analysis women who had positive thyroid peroxidase antibodies.
“This is very interesting, because it really raises the question of whether we should be treating TSH, even to the lower half of the normal range, to see if that can improve outcomes,” she said. “We are looking for modifiable things that we can treat to try to improve fertility, so if we can identify some cause – like a hormonal cause – we may be able to improve conception outcomes and reduce the need for invasive treatment.”
Based in part on the strength of these findings, Dr. Fourman said she and her collaborators are planning a prospective study to see whether treating women with infertility to achieve a TSH of less than 2.5 can speed time to conception and reduce the need for invasive infertility treatment.
Dr. Fourman reported no conflicts of interest and no external sources of funding.
SOURCE: Fourman, L, et al. ENDO 2018, Abstract SAT-288.
REPORTING FROM ENDO 2018
