Clinical trial NCT00884403: Gestational Age is Underestimated by Menstrual Dating Compared to Ultrasound Dating in Those Undergoing Abortion up to 20 Weeks
Official title: Gestational Age is Underestimated by Menstrual Dating Compared to Ultrasound Dating in Those Undergoing Abortion up to 20 Weeks
Study type: OBSERVATIONAL
Overall status: TERMINATED
Conditions: Abortion
Keywords: abortion
pregnancy dating
gestational age
ultrasound
Lead sponsor: University of British Columbia
Sponsor class: OTHER
Collaborators: name: Women's Health Research Institute of British Columbia
First posted: 2009-04-20
Enrollment: 415
Sex: FEMALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: women in British Columbia who obtained abortion up to twenty weeks gestational age.

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.

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.

Eligibility criteria: 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.

Primary outcomes:
measure: Difference between actual gestational age assessed by pre-operative ultrasound and gestational age estimated by menstrual dating
timeFrame: 1 year
Secondary outcomes:
measure: Correlation of the difference between AGA and LMP dating with demographic and obstetrical history factors.
timeFrame: 1 year
Other outcomes:
Locations:
city: Vancouver
country: Canada
facility: BC Women's Hospital CARE Program
state: British Columbia
Study officials:
affiliation: University of British Columbia
name: Wendy V. Norman, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Norman WV, Bergunder J, Eccles L. Accuracy of gestational age estimated by menstrual dating in women seeking abortion beyond nine weeks. J Obstet Gynaecol Can. 2011 Mar;33(3):252-7. doi: 10.1016/s1701-2163(16)34826-5.