Roles of glucocorticoids in human parturition: a controversial fact?

Area of Science:

• Reproductive Endocrinology
• Maternal-Fetal Medicine
• Hormonal Regulation of Parturition

Background:

• Glucocorticoids' role in parturition is established in domestic animals but debated in humans.
• Synthetic glucocorticoids do not consistently affect human gestation length, creating controversy.
• Endogenous glucocorticoids may be crucial for human parturition, but require specific conditions.

Purpose of the Study:

• To review existing literature on glucocorticoids in human parturition.
• To provide evidence supporting a significant role for glucocorticoids in human birth.
• To elucidate the interplay between glucocorticoids, estrogen, and parturition.

Main Methods:

• Review of scientific literature on glucocorticoids and human parturition.
• Analysis of the effects of synthetic versus endogenous glucocorticoids on the fetal HPA axis.
• Examination of placental and fetal membrane mechanisms involved in parturition.

Main Results:

• Synthetic glucocorticoids (dexamethasone, betamethasone) can suppress the fetal HPA axis, potentially inhibiting labor.
• Endogenous glucocorticoids are inactivated by placental 11β-HSD2, allowing simultaneous rises in cortisol and estrogen.
• Local glucocorticoids may enhance prostaglandin, estrogen, and CRH production, facilitating parturition.

Conclusions:

• High intrauterine estrogen concentrations are likely necessary for glucocorticoids to initiate human parturition.
• Endogenous glucocorticoids, especially locally produced ones, play a vital role in human labor.
• The placental 11β-HSD2 enzyme is critical in modulating the maternal-fetal glucocorticoid relationship during gestation.