Pregnancy-Induced Analgesia - A Longitudinal Study of DNIC

This study is currently recruiting participants. (see Contacts and Locations)
Verified June 2013 by University of Washington
Sponsor:
Collaborator:
Stanford University
Information provided by (Responsible Party):
Ruth Landau, University of Washington
ClinicalTrials.gov Identifier:
NCT00867945
First received: March 20, 2009
Last updated: June 17, 2013
Last verified: June 2013
  Purpose

The investigators hypothesize that pregnancy-induced analgesia might be the result of enhanced descending noxious inhibitory activity.


Condition
Pregnancy

Study Type: Observational
Study Design: Observational Model: Case Control
Time Perspective: Prospective
Official Title: Pregnancy-Induced Analgesia - A Longitudinal Study of DNIC

Further study details as provided by University of Washington:

Primary Outcome Measures:
  • To use psychophysical tests to study both the inhibitory and excitatory pain pathways using the DNIC paradigm and temporal summation longitudinally during pregnancy, compared to an age-matched control group of non-pregnant women. [ Time Frame: Pregnant Cohort - each trimester and postpartum; Control Cohort - twice a menstrual cycle, 4 cycles, over 7 months ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Questionnaires, pain scores, amount of analgesics required, overall experience of labor and delivery [ Time Frame: Questionnaires - Same as Primary Outcome Measure; other three measures - at delivery ] [ Designated as safety issue: No ]

Estimated Enrollment: 60
Study Start Date: March 2009
Estimated Study Completion Date: December 2013
Estimated Primary Completion Date: December 2013 (Final data collection date for primary outcome measure)
Groups/Cohorts
1. Pregnant Women
2. Non-Pregnant Controls
3. IVF controls

Detailed Description:

Pregnancy-induced analgesia has been described in several studies (Gintzler 1980; Sander and Gintzler 1987; Jarvis et al. 1997). Obvious mechanisms underlying pregnancy-induced analgesia involve hormonal changes during gestation (Fillingim and Ness 2000). Existing studies during pregnancy and peripartum have focused on standard characteristics of nociception, using non-dynamic quantitative sensory testing such as pain threshold/tolerance or suprathreshold stimuli (Goolkasian and Rimer 1984; Sengupta and Nielsen 1984; Cogan and Spinnato 1986; Dunbar et al. 1988; Whipple et al. 1990; Shapira et al. 1995; Saisto et al. 2001; Bajaj et al. 2002; Carvalho et al. 2006; Ohel et al. 2007), with its relative limitations of studying only the afferent nociceptive input produced in the peripheral nervous system.

The two systems that are of prime importance in pain modulation within the CNS are the inhibitory system (descending noxious inhibitory control (DNIC)) and the excitatory system, with the balance of pain being more heavily influenced by the former (Godfrey and Mackey 2008).

The primary aim of this study is to use psychophysical tests to study both the inhibitory and excitatory pain pathways using the DNIC paradigm and temporal summation longitudinally during pregnancy, compared to an age-matched control group of non-pregnant women.

We added the In Vitro Fertilization (IVF) sub-population to the PIA study to study them as a control group (in addition to studying non-pregnant controls and pregnant women). We are studying this sub population prior to their egg retrieval procedure and a short phone survey with participants post egg-retrieval. If the subject becomes pregnant, we would recruit them to enroll in the PIA pregnant population cohort.

  Eligibility

Ages Eligible for Study:   18 Years to 45 Years
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

maternity clinic - Pregnant Cohort community sample - Non-pregnant Control Cohort

Criteria

Inclusion Criteria:

  • Pregnant Cohort: Inclusion criteria for participation are (1) women aged between 18 and 45 yr, (2) nulliparous or ASA physical status class I or II women, (3) singleton pregnancy, (4) no more than 14 completed weeks gestational age at the time of enrollment into the study, (5) uncomplicated pregnancy, and (6) delivery planned to be conducted at UW/Stanford University.
  • Non-pregnant Control Cohort: Inclusion criteria for participation are (1) women aged between 18 and 45 yr, (2) nulliparous or ASA physical status class I or II women, (3) and not planning on taking oral-contraceptives or carrying a hormonal-coated IUD.

Non-inclusion Criteria:

  • Pregnant Cohort: Non-inclusion criteria are (1) multiparous women, (2) non-English speaking women (subjects have to be able to understand the DNIC procedure and answer questionnaires), (3) women unable to understand the concept of VNPS at the time of informed consent (involving mental health issues), (4) a history of anxiety or depression, or chronic consumption of opiates, antidepressants, or anticonvulsants; and (5) intake of opioids, acetaminophen, or NSAIDs 48h prior to the psychophysical test.
  • Non-pregnant Control Cohort: Non-inclusion criteria are the same as the Pregnant Cohort as well as (6) irregular menstrual cycles (defined as < 21 days or > 35 days).

Exclusion Criteria:

  • Pregnant Cohort: Exclusion criteria is a pregnancy complicated by preeclampsia or preterm delivery (< 37 weeks gestation).
  • Non-pregnant Control Cohort: Exclusion criteria is development of irregular cycles.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00867945

Contacts
Contact: Lisa Y Flint, BS (206) 543-7817 lyflint@u.washington.edu

Locations
United States, California
Stanford University School of Medicine Recruiting
Stanford, California, United States, 94305
Contact: Brendan Carvalho, MBBCh    650-861-8607    bcarvalho@stanford.edu   
Contact: Sebastian Ruehlmann, MD       ruehlmail@gmail.com   
Principal Investigator: Brendan Carvalho, MBBCh         
United States, Washington
University of Washington Recruiting
Seattle, Washington, United States, 98195-6540
Contact: Ruth Landau, MD    206-543-2187    rulandau@u.washington.edu   
Principal Investigator: Ruth Landau, MD         
Sponsors and Collaborators
University of Washington
Stanford University
Investigators
Principal Investigator: Ruth Landau, MD University of Washington
  More Information

No publications provided

Responsible Party: Ruth Landau, Professor, University of Washington
ClinicalTrials.gov Identifier: NCT00867945     History of Changes
Other Study ID Numbers: 35811-A
Study First Received: March 20, 2009
Last Updated: June 17, 2013
Health Authority: United States: Institutional Review Board

ClinicalTrials.gov processed this record on October 20, 2014