Objective: To describe the relation between PRL and hCG, T 3 , T 4 , fT 4 , TSH, E 2 and P 4 levels in normal pregnancies and those complicated with GTD. Method: Twenty women, 10 with normal pregnancy and 10 with molar pregnancy were studied. The differences between them and the relation between prolactin (PRL) and human chorionic gonadotropin (hCG), estradiol and thyroid hormones, thyroid stimulating hormone (TSH) and progesterone, was determined by Mann–Whitney U -test and Pearson's correlation coefficient, respectively. Results: HCG, estradiol and thyroid hormones were higher in molar pregnancy, but PRL and progesterone were similar and TSH was lower in molar pregnancy. A negative correlation was found between PRL level and all the hormones in normal pregnancy, with the exception of TSH, and in molar pregnancy there was a positive correlation of PRL with all hormones. Conclusion: HCG, E 2 , T 3 , T 4 , fT 4 levels were higher in the group with molar pregnancy. Differences in correlation analysis suggest different endocrine regulation mechanisms in molar and normal pregnancies.