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Gestational Age is Underestimated by Menstrual Dating Compared to Ultrasound Dating in Those Undergoing Abortion up to 20 Weeks

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ClinicalTrials.gov Identifier: NCT00884403
Recruitment Status : Completed
First Posted : April 20, 2009
Last Update Posted : March 17, 2014
Information provided by (Responsible Party):

Study Description
Brief Summary:
Several large trials report gestational dating by last menstrual period (LMP) overestimates gestational age (GA) vs. ultrasound (US) by approximately one week. Previous studies examined only term pregnancies. The investigators hypothesize an opposite tendency in women seeking abortion. This is an observational study undertaken by chart review.

Condition or disease

Detailed Description:
Retrospective cohort study by chart review. We propose to review the charts of four thousand women obtaining abortion in British Columbia, BC. Data will be extracted from the charts of women who obtained abortions between January first 2002 and June 30, 2008 inclusive at two abortion clinics in Vancouver, British Columbia: BC Women's Hospital CARE program, and the Elizabeth Bagshaw Women's Clinic. Specifically we will record age, parity, date of LMP, presence of regular cycles, ultrasound estimation of gestational age, ultrasound measurements: crown rump length, bi-parietal diameter, gestational sac diameter if available, date of abortion, estimation of gestational age by examination of the products of conception, and fetal foot length if available. Further we will record associated factors such as contraception at time of conception, intravenous drug use, and regularity of menstrual cycle. We will calculate the gestational age at time of abortion by the LMP date, by the ultrasound date reported, ultrasound date based on the Hadlock protocol by the reported CRL and similarly BPD as well as calculating the gestational age based on the recorded fetal foot length.

Study Design

Study Type : Observational
Actual Enrollment : 415 participants
Observational Model: Cohort
Time Perspective: Retrospective
Official Title: Gestational Age is Underestimated by Menstrual Dating Compared to Ultrasound Dating in Those Undergoing Abortion up to 20 Weeks
Study Start Date : September 2008
Primary Completion Date : June 2009
Study Completion Date : June 2009

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U.S. FDA Resources

Groups and Cohorts

Outcome Measures

Primary Outcome Measures :
  1. Difference between actual gestational age assessed by pre-operative ultrasound and gestational age estimated by menstrual dating [ Time Frame: 1 year ]

Secondary Outcome Measures :
  1. Correlation of the difference between AGA and LMP dating with demographic and obstetrical history factors. [ Time Frame: 1 year ]

Eligibility Criteria

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Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Sampling Method:   Probability Sample
Study Population
women in British Columbia who obtained abortion up to twenty weeks gestational age.

Inclusion Criteria:

  • Included charts of women who obtained abortion up to twenty weeks gestational age must have a stated LMP date, a pre-operative ultrasound, a viable pregnancy at the time of the abortion and an assessment of the gestational age of the products of conception.
Contacts and Locations

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To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00884403

Canada, British Columbia
BC Women's Hospital CARE Program
Vancouver, British Columbia, Canada
Sponsors and Collaborators
University of British Columbia
Women's Health Research Institute of British Columbia
Principal Investigator: Wendy V. Norman, MD University of British Columbia
More Information

Responsible Party: University of British Columbia
ClinicalTrials.gov Identifier: NCT00884403     History of Changes
Other Study ID Numbers: H08-01332
First Posted: April 20, 2009    Key Record Dates
Last Update Posted: March 17, 2014
Last Verified: March 2014

Keywords provided by University of British Columbia:
pregnancy dating
gestational age