Serum prolactin levels across pregnancy and the establishment of reference intervals

Background: Reference intervals (RIs) play key roles in clinical diagnosis, treatment and prognosis. However, RIs for clinical testing tend to be confined to the general population, and RIs for pregnant women are not very comprehensive. In this study, we establish RIs for prolactin (PRL) in healthy pregnant and postpartum women in the Chinese population. Methods: Healthy pregnant women (n = 378) were divided into groups according to whether they were in the first, second or third trimester of pregnancy. Healthy postpartum women (n = 493) were separated into four groups according to mode of delivery as follows: postvaginal (24 and 48 h) or postcesarean (24 and 48 h). Healthy, non-pregnant women (n = 123) were enrolled as a control group. Serum PRL levels were measured by electrochemiluminescence immunoassay, and RIs were established for each group. Results: The RIs for PRL were as follows: healthy non-pregnant women, 178.89-757.52 mu IU/mL; first trimester, 621.20-3584.00 mu IU/mL; second trimester, 1432.00-5349.68 mu IU/mL; third trimester, 4087.33-9733.65 mu IU/mL; 24 and 48 h postvaginal delivery (combined), 7865.36-10998.86 mu IU/mL; and 24 and 48 h postcesarean delivery, 4556.41-7675.99 and 6578.45-9980.45 mu IU/mL, respectively. Conclusions: PRL RIs for pregnant women were established according to trimester, days postpartum and mode of delivery, thus providing a clinical reference for medical staff.