Elsevier

The Lancet

Volume 355, Issue 9207, 11 March 2000, Pages 877-881
The Lancet

Articles
Accuracy of assessment of pregnancy duration by women seeking early abortions

https://doi.org/10.1016/S0140-6736(99)10170-3Get rights and content

Summary

Background

Advances in medical abortion might allow women seeking early abortions to terminate their pregnancies safely and effectively without medical supervision. We investigated whether such women can calculate pregnancy duration accurately, a key step in unsupervised use.

Methods

422 women seeking first-trimester abortions in two clinics (Pune, India, and Atlanta, USA) used a simple worksheet and calendar to calculate the duration of gestation from the date of last menstrual period (LMP) and/or of unprotected intercourse. Clinicians then used standard clinic practices to estimate pregnancy duration. We compared the two sets of estimates, focusing on women who fell into the “caution zone” (ie, had pregnancy durations >8 weeks according to providers, but ≥8 weeks by their own estimates).

Findings

The participants were generally representative of the women seeking abortion at the two clinics. 217 (97.7%) of 222 women in Atlanta and 173 (86.5%) of 200 in Pune could produce an estimate of pregnancy duration. Most (85.4% in Atlanta; 93.6% in Pune) of these estimates were within 2 weeks of those made by providers. For estimates based on LMP, only 10.0% (exact 95% Cl 6.2–15.0) of women in Atlanta and 9.8% (5.8–15.3) in Pune fell into the caution zone. For estimates based on a date of intercourse, just 7.7% (4.0–13.1) of women in Atlanta and 3.4% (0–17.8) in Pune fell into the caution zone, although fewer women could use this method.

Interpretation

The vast majority of women seeking first-trimester abortion in this study could accurately calculate pregnancy duration within a margin of error clinically inconsequential for safe use of unsupervised medical abortion.

Introduction

Each year about 180 million women worldwide become pregnant.1 Very little research has explored women's own understanding of a key feature of pregnancy—duration of gestation. A few studies in women who carried their pregnancies to term compared various methods to assess duration of gestation according to how well the methods predict delivery dates,2, 3 diagnose prematurity, or identify premature infants at greatest risk of death.4, 5 None of those studies looked at women's own abilities to estimate their pregnancy durations.

For many women, however, pregnancy does not lead to birth. Yet no study has investigated estimation of pregnancy duration in relation to induced abortion. There are good reasons for this lack of research. Conventional methods of induced abortion require the woman to visit a health-care provider. During the visit, the clinician calculates the pregnancy duration and treats the woman according to a professional estimate of this variable. In this context, a woman does not need to calculate her pregnancy duration.

Now, however, advances in early medical abortion create a compelling reason to study women's ability to self-assess pregnancy duration. In particular, the widely used mifepristone-misoprostol regimen consists simply of two sets of pills, typically taken orally 48 h apart. The regimen has proved safe, effective, and acceptable in both more developed and less developed countries.6, 7, 8 In principle, at least, the regimen is so safe when used at the earliest durations of gestation (taken as 8 weeks and under for the purposes of this paper)9 that women could be counselled about mifepristone-misoprostol during routine reproductive health care and could keep a dose of the treatment on hand for use when needed. Medical involvement and expense would be limited to necessary back-up.

Such advance distribution protocols, however, are currently unknown. Typical protocols require three clinic visits: one to confirm pregnancy, assess pregnancy duration, and administer mifepristone; a second to give misoprostol and observe that all is well; and a third to confirm that the abortion is complete and to offer a back-up procedure if it is not. Is such strict, costly, and intrusive medical involvement warranted? The answer depends on whether women themselves can manage several tasks traditionally handled by medical professionals, including diagnosis of the need for abortion, and later, accurate assessment of whether the abortion is complete.10 Since the efficacy and safety of mifepristone-misoprostol decrease with advancing gestation,9, 11 perhaps the most critical of these steps is correct self-assessment of pregnancy duration before the treatment is started.

Data from a multicentre trial of medical abortion by means of mifepristone-misoprostol8 suggest that women do know the information necessary to underpin accurate assessment of pregnancy duration: 99.9% of the 799 Chinese, Cuban, and Indian women in that study offered an exact date (accurate or not) for the start of their last menstrual period (LMP) and 92.4% of estimates derived from the dates women offered fell within 1 week of physicians' estimates. Moreover, estimates based on the dates reported by the women predicted the likelihood of a complete medical abortion better than physicians' estimates.11 That dataset, however, precluded a full exploration of self-assessment of pregnancy duration because it excluded women whose LMP had been more than 56 days before presentation (according to clinical estimates). Also, participants were not required to convert the dates they gave into durations of pregnancy. To investigate more fully, we undertook this observational study.

Section snippets

Participants

The study took place between May, 1997, and March, 1998, at two large, urban clinics (a free-standing abortion clinic in Atlanta, USA, and a large government-funded clinic in Pune, India). Women presenting at these clinics for first-trimester abortion were informed about the study and were eligible if they believed that their pregnancy duration was less than 13 weeks, although knowledge of the dates of the LMP or the date of unprotected intercourse was not a requirement. We excluded women

Results

In each site, we failed to reject our null hypothesis that at least 90% of women could assess their gestational durations well enough to avoid the caution zone. Of the first-trimester abortion clients seen during the study period, 222 (11.5%) of 1933 at the Atlanta clinic and 200 (64.1%) of 312 in Pune took part in the study. In Atlanta, study staff were available during only a small proportion of the clinic shifts, and we do not know the total number of eligible women, or any of their

Discussion

For this study, we took the providers' estimates (irrespective of the method used to generate them) as correct. These estimates would govern routine provision of mifepristone-misoprostol, and we wanted to see how closely women on their own could match the estimates they would typically be given by medical professionals.

We found that the vast majority of women presenting for first-trimester abortions in Atlanta and in Pune and equipped only with a simple worksheet and calendar could judge

References (16)

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