The role of progesterone preparations in the prevention of premature birth: a modern view of the problem

Despite significant progress achieved in healthcare, preterm birth is an urgent problem in modern obstetrics. The preterm birth can be caused by various risk factors: for example, an ascending infection can trigger the onset of uterine contractions, cervical shortening followed by infection of the fetal membranes, amniotic fluid, and, in rare cases, the fetus itself. In most cases, the infectious and inflammatory process is the etiopathogenetic factor of isthmic-cervical insufficiency (ICI), one of the common causes of late miscarriages and preterm births. The period between 14 and 20 weeks of gestation is the most critical time for the development of ICI. The dynamic ultrasound cervicometry once every 7–14 days from week 16 through week 24 of pregnancy is recommended to the patients with ICI, as well as pregnant women in the high-risk group. Most professional societies guidelines addressing this issue recommend all pregnant women to perform routine transvaginal cervicometry during the second ultrasound screening for the timely formation of risk groups and optimization of approaches to the patient management. The following groups of drugs are used to prevent preterm birth: micronized progesterone, slow calcium channel blockers, β-adrenergic agonists, and non-steroidal anti-inflammatory drugs. The use of progesterone drugs to prevent preterm birth has generated much debate. Thus, the availability of several forms of progesterone and various routes of administration determine the complexity of the drug therapy. Micronized progesterone is the only progesterone drug that was approved for use after 20 weeks of gestation. The vaginal micronized progesterone has been found to be highly effective in the prevention of preterm birth, significantly reduce neonatal mortality and improve infant morbidity outcomes.