Abstract
Prolactin is affected by several factors: sex, age, BMI, sleep duration, menopausal status, and menstrual cycle phases. However, previous studies on this topic have caused some confusion, and the duration from the wake-up hour to sample collection has not been correlated with prolactin levels. This study aims to assess the correlation of prolactin levels with sleep duration, the durations from waking to sample collection and some demographic factors. To compare serum prolactin levels between males, reproductive females, and menopausal females and between menstrual cycle phases. In a study of 192 healthy adult subjects. Prolactin was compared between males, reproductive females, and menopausal females and different ages, BMI groups, and different menstrual cycle phases. The correlation between prolactin levels with the duration from waking to sample collection, sleep duration, age, BMI, and waist circumference were assessed. The highest median prolactin was among reproductive females, and menopausal females showed the lowest prolactin level compared to reproductive females and males. Prolactin levels were not significantly different between phases of the menstrual cycle. The only significant predictor of prolactin levels in males and females was the duration between the wake-up hour and sample collection. The duration from the wake-up hour to sample collection significantly predicts prolactin levels in healthy subjects. Prolactin levels are highest in reproductive females and lowest during menopause, while no significant differences were found between menstrual cycle phases. Sleep duration and other demographic factors are not significantly correlated with prolactin levels in healthy subjects with normal prolactin levels.