A cannulated prolactin series reduces the need for further investigations in women with infertility and lowers the number of false positive screening prolactin measurements
Leigh Searle, Simon McDowell, Robin Willink, Jeremy Krebs
Abstract
BACKGROUND: The prevalence of hyperprolactinaemia in women presenting for infertility investigation has been found to be up to 17%, and many of these women are asymptomatic. Prolactin levels may be elevated by stress, including phlebotomy and not be of clinical significance. A cannulated prolactin study may be a useful way to discriminate this. AIM: To determine the utility of a cannulated prolactin series in women presenting with infertility who have a raised prolactin measurement at referral for first fertility consultation. MATERIALS AND METHODS: All women referred to two fertility centres had a prolactin level measured prior to first appointment over a two-year period. If the level remained elevated on the second measure after macroprolactin precipitation, women were referred for a cannulated prolactin series. If the prolactin concentration fell within the reference range during the series then the result was regarded as normal. RESULTS: Forty-four (2.7%) of 1660 women seen for a first specialist appointment had persistently raised prolactin concentrations after two samples and were referred for a cannulated series. The proportion of women whose prolactin was found to be normal during the cannulated prolactin series was 61% (95% CI 47-74%). Even in patients with a referral prolactin of greater than 1000 mU/L, 45% had a normal two-hour cannulated series. CONCLUSION: A high proportion (61%) of women with raised prolactin at time of referral for first specialist appointment had a normal prolactin after a two-hour cannulated series. A cannulated prolactin study can avoid unnecessary further investigations in these women.