Norman Wendy V, Bergunder Jeannette, Eccles Lisa
Department of Family Practice, University of British Columbia, Vancouver, BC.
J Obstet Gynaecol Can. 2011 Mar;33(3):252-7. doi: 10.1016/s1701-2163(16)34826-5.
We sought to quantify the accuracy of estimating gestational age by reported last menstrual period among women seeking surgical abortion. We observed that women seeking surgical abortion underestimated their gestational age when making the appointment, leading to poor allocation of resources. This tendency to underestimate has not previously been reported and differs from the accurate dating reported among women choosing either medical abortion or continuation of the pregnancy.
We performed a retrospective review of randomly selected medical records for women with abortions scheduled at 9 to 20 weeks' gestation (n = 415) at two clinics in Vancouver between 2002 and 2008.
The mean gestational age calculated by menstrual dates (14.3, SD 3.9) was 1.2 (95% CI 0.9 to 1.4) weeks less than that calculated by ultrasound (15.5, SD 3.4) (P < 0.001). Greater gestational age was associated with a larger discrepancy (r = 0.192, P < 0.001). Variables other than gestational age (maternal age, parity, previous abortions, illicit drug use, and contraceptive method at conception) were not significant predictors of inaccurate menstrual dating.
Women seeking surgical abortion for pregnancies of 9 to 20 weeks underreport gestational age by an average of 1.2 weeks using menstrual dating. We found that women who intended to continue with their pregnancy overestimated their gestational age, those seeking very early abortion estimated most accurately, and those seeking surgical abortion at more than nine weeks had a clinically significant underestimation of their gestational age. Clinicians referring and counselling women who are considering surgical abortion must facilitate timely access to clinical or ultrasound dating of their pregnancy.
我们试图量化在寻求手术流产的女性中，根据报告的末次月经日期估算孕周的准确性。我们观察到，寻求手术流产的女性在预约时低估了自己的孕周，导致资源分配不佳。这种低估的趋势此前尚未见报道，且与选择药物流产或继续妊娠的女性所报告的准确孕周不同。
我们对2002年至2008年期间在温哥华两家诊所计划进行9至20周妊娠流产的女性的随机选择的病历进行了回顾性研究（n = 415）。
根据月经日期计算的平均孕周（14.3，标准差3.9）比根据超声计算的孕周（15.5，标准差3.4）少1.2周（95%可信区间0.9至1.4）（P < 0.001）。孕周越大，差异越大（r = 0.192，P < 0.001）。除孕周外的其他变量（母亲年龄、产次、既往流产史、非法药物使用情况以及受孕时的避孕方法）不是月经日期估算不准确的显著预测因素。
寻求9至20周妊娠手术流产的女性使用月经日期估算时，平均低估孕周1.2周。我们发现，打算继续妊娠的女性高估了她们的孕周，寻求极早期流产的女性估算最准确，而寻求9周以上手术流产的女性在临床上显著低估了她们的孕周。为考虑手术流产的女性提供转诊和咨询的临床医生必须促使她们及时获得妊娠的临床或超声孕周测定。
