Mieke Soens, MD, of BWH’s Department of Anesthesiology and Pain Management, and colleagues in the Strichartz lab have found – using a preclinical model – that progesterone levels in utero may contribute to abnormal pain response during adulthood. This study provides some of the first evidence that progesterone is involved in pain pathway development, and suggests that premature babies may be more sensitive to pain as adults due to a lack of progesterone exposure. The team’s findings appear in Anesthesia & Analgesia.

In the past two decades, the rate of premature births in humans has increased by 30 percent, and life-saving fetal surgeries have increased in frequency. Since progesterone is made by the mother mostly in the second half of gestation, premature infants often lack full exposure to progesterone. Progesterone is a female hormone involved in the menstrual cycle, pregnancy and embryonic development. It is also an antihyperalgesic (anti-pain sensitivity) agent. The BWH team hypothesized that progesterone may play an important role in the development of pain-sensing pathways and may protect the fetus. In preclinical models, the team tested sensitivity to tactile, mechanical and thermal stimuli after exposure to progesterone. The team found that progesterone permanently altered the development of pain-sensing pathways.

“In the future, we will generate more much needed research in this exciting field, particularly to help determine if progesterone treatment can prevent altered pain responses in preterm babies,” said Soens.