Endogenous Pain Facilitation and Inhibition in Postpartum Women

Wake Forest University (WFU)

Status: Completed

Conditions: Pain Inhibition and Facilitation in Post Partum Women

Study type: Observational

Funder types: Other

Identifiers

NCT01843517

IRB00022603

Details and patient eligibility

About

This study seeks to further understand these three observations - (1) that the time period surrounding childbirth accelerates recovery from pain after injury (2) that this likely reflects dampened facilitating mechanisms and exaggerated inhibitory mechanisms, and (3) that stress may interfere with this protection. In this study the investigators will compare women within 2 weeks of delivery to age matched controls and anticipate that pain inhibition is increased after delivery, pain facilitation is decreased, and that there is a relationship between these pain responses and the degree of pre-existing stress.

Full description

Nearly half of the world's population experiences labor and delivery processes which are associated with microscopic or gross tissue injury to the mother. Since this experience is widespread and occurs relatively early in life, the psychosocial, medical, and financial consequences of chronic pain following childbirth could be enormous. Surprisingly, previous studies with long term follow up of new mothers have included pain as a secondary measure and / or have focused on prevalence of pain without determining whether pain predated delivery or even pregnancy itself. The investigators recently performed a long term follow up study of over 1,200 women, and noted that pain which began during the childbirth itself was surprisingly rare in comparison to other physical injuries. Additionally, two central factors hypothesized to confer risk of chronic pain after other injuries including surgery, pre-dating chronic pain and degree of tissue and nerve injury, contributed minimally to the acute and sub-acute pain after childbirth. These two observations, low incidence of chronic pain and minimal effect of degree of tissue injury and history of chronic pain on sub-acute pain, point towards a potential protective effect of pregnancy or delivery on the response to physical injury.

Enrollment: 80 patients

Sex: Female

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• female
• 10-14 days postpartum, term vaginal delivery
• breastfeeding (postpartum women)
• health non-pregnant female (nulliparous or at least 1 year beyond delivery)

Exclusion criteria

• Allergy to chili peppers
• pregnant
• pain medication (narcotic or non-narcotic) within 4 hours of study visit Average pain in the 24 hours preceding the study visit >3. Postpartum women that score >13 on the Edinburgh Postnatal Depression Scale

Trial design

80 participants in 2 patient groups

endogenous pain facilitation

Description:

Pain facilitation is studied by a simple test of applying over the counter capsaicin cream to the skin for only 30 min, then removing it and heating the skin to a non-noxious temperature.

endogenous pain inhibition

Description:

Pain inhibition is studied by a simple test of mild pain on one area of the body reducing response to a pain stimulus in another area.