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

Status

Terminated

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT00884403

Enrollment

415

Registered

2009-04-20

Start date

2008-09-30

Completion date

2009-06-30

Last updated

2018-05-04

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Abortion

Keywords

abortion, pregnancy dating, gestational age, ultrasound

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.

Interventions

None listed

Study design

Observational model

COHORT

Time perspective

RETROSPECTIVE

Eligibility

Sex/Gender

FEMALE

Age

18 Years to No maximum

Healthy volunteers

Yes

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.

Design outcomes

Primary

Measure	Time frame
Difference between actual gestational age assessed by pre-operative ultrasound and gestational age estimated by menstrual dating	1 year

Secondary

Measure	Time frame
Correlation of the difference between AGA and LMP dating with demographic and obstetrical history factors.	1 year

Countries

Canada

Outcome results