Evolution of macroprolactinomas during pregnancy: A cohort study of 85 pregnancies.

Objective: Pregnancy in patients with macroprolactinomas has been associated with a higher risk of pituitary tumour growth. However, the incidence and risk factors remain unclear. We aimed to evaluate the evolution of macroprolactinomas during pregnancy and to identify potential risk factors.

Design, Patients And Measurements: This is a two-centre, retrospective, observational study. All patients with macroprolactinomas, treated with a dopamine receptor agonist (DA), and who had at least one pregnancy were included.

Results: There were a total of 85 viable pregnancies in 46 patients with macroprolactinomas. At diagnosis, mean size of pituitary adenomas was 17.9 ± 8.2 mm (10-43 mm) and mean plasma prolactin level was 1012.2 ± 1606.1 µg/L (60-7804 µg/L). Tumour growth-related symptoms were identified 12 times in 9 patients (19.6%) including 3 cases of apoplexy. Restarting, changing and/or increasing DA treatment was effective in 10 cases. Emergency surgery had to be performed twice (due to pituitary apoplexy). Patients with tumour progression tended to present with larger tumours after initial treatment and before pregnancy (9.9 vs 5.9 mm; P = .0504 and 11.5 vs 7.3 mm; P = .0671, respectively), whereas adenoma size at diagnosis did not seem to be a significant factor. The obstetrical outcomes were comparable to the general population.

Conclusions: Symptomatic growth of macroprolactinoma during pregnancy occurred in 19.6% of medically treated patients. This risk seems higher for patients with poor initial tumour response to the DA treatment. Tumour progression is generally well controlled with medical treatment during pregnancy.