“…However, concerning maternal progesterone levels, the results have been inconclusive and even contradictory. Although some authors found high levels of progesterone at 28 to 32 weeks' gestation in pregnant people having preterm labor, 16 others have found the contrarylow levels in both plasma 17 and in saliva. 17 Therefore, the role and the predictive capability of progesterone for these complications remain unclear.…”