Conventional and sustained-release oral natural micronised progesterone in luteal phase support, threatened miscarriage, preterm birth, and high-risk pregnancy: a review

Exogenous progesterone is used to manage obstetric indications associated with reduced progesterone activity. This review examined evidence for oral natural micronised progesterone (NMP) and NMP-SR, a sustained-release formulation designed to overcome the limitations of conventional oral NMP. Oral NMP was effective for luteal phase support during assisted reproduction, and prevention of threatened spontaneous miscarriage and preterm delivery. NMP-SR was comparable to dydrogesterone for luteal phase support during assisted reproduction and maintenance of high-risk pregnancies. By releasing progesterone gradually and circumventing first-pass metabolism, NMP-SR elicits the desired therapeutic effect with added benefits of better bioavailability, once-daily dosing, and improved tolerability.