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.
koakes@frontlinemedcom.com
SOURCE: Fourman, L, et al. ENDO 2018, Abstract SAT-288.