Long-term effect study

We evaluated the long-term effect of PMG treatments vs P4 (n=6 in LPS+Vehicle group, n=5 in LPS+P4 group, and n=6 in LPS+PMG group) (Figure 1, ​,B).B). Mice that delivered preterm (n=6 in LPS group and n=2 in LPS+P4 group) were euthanized by carbon dioxide inhalation during PTL. The animals that carried pregnancy to term were sacrificed on GD 19.5 during TL. Animals that carried pregnancy postterm (5 from 6 mice in the LPS+PMG group) were sacrificed on GD 20.5 (24 hours after the average delivery time). The intact uterus of each female mouse was removed and the total number of fetuses, their vital signs, and fetal and placental weights were taken into account.

In a replicate group of animals, pregnant mice that did not deliver preterm after LPS±PMG injection were sacrificed before term delivery on GD 18.75 from 6 to 8 PM. We recorded the maternal weight gain, litter size, fetal and placental weights and fetal viability (Table 4). The maternal (myometrium, plasma etc.) and fetal tissues (placenta, amniotic fluid) were collected for analysis.

Fetal and placental outcome measurements of pregnant mice induced with LPS and treated with PMG (GD 18.75)

Data are presented as mean±standard deviation, unless otherwise indicated.

GD, gestational day; LPS, lipopolysaccharide; PMG, synthetic progestin.

Shynlova et al. Promegestone delays preterm labor in mice. Am J Obstet Gynecol 2021.