Accuracy of serum beta-human chorionic gonadotropin cutoff values at 42 and 49 days' gestation

Accuracy of serum human chorionic gonadotrophin for estimating gestational age in the first trimester of pregnancy: population-based study

This study determined the accuracy of first trimester serum Human Chorionic Gonadotrophin (HCG) for estimating gestational age (GA). We included 273,584 singleton livebirths that had a first trimester ultrasound and measured serum HCG at 4-12 weeks gestation in XXX from 2012-2018. We estimated HCG accuracy compared to known GA, within a boundary of +/- 1 week. Between 4-8 weeks gestation, sensitivity of HCG was over 88%, and specificity over 51%. However, at 9-12 weeks, sensitivity declined from 72% to 0%, and specificity rose from 86% to 100%. At all GA, the Positive Predictive Value was consistently under 42%, while Negative Predictive Values were over 96%. Within epidemiological studies in which GA is otherwise unknown, first trimester serum HCG may aid somewhat in estimating GA between 4 to 6 weeks gestation, but much less so thereafter. Thus, there remains an ongoing need for an accurate method for estimating missing GA within large datasets.

[Role of ultrasound in elective abortions]

Ultrasound plays a fundamental role in the management of elective abortions. Although it can improve the quality of post-abortion care, it must not be an obstacle to abortion access. We thus studied the role of ultrasound in pregnancy dating and possible alternatives and analyzed the literature to determine the role of ultrasound in post-abortion follow-up. During an ultrasound scan, the date of conception is estimated by measurement of the crown-rump length (CRL), defined by Robinson, or of the biparietal diameter (BPD), as defined by the French Center for Fetal Ultrasound (CFEF) after 11 weeks of gestation (Robinson and CFEF curves) (grade B). Updated curves have been developed in the INTERGROWTH study. In the context of abortion, the literature recommends the application of a safety margin of 5 days, especially when the CRL and/or BPD measurement indicates a term close to 14 weeks (that is equal or below 80 and 27mm, respectively) (best practice agreement). Accordingly, with the ultrasound measurement reliable to±5 days when its performance meets the relevant criteria, an abortion can take place when the CRL measurement is less than 90mm or the BPD less than 30mm (INTERGROWTH curves) (best practice agreement). While a dating ultrasound should be encouraged, its absence is not an obstacle to scheduling an abortion for women who report that they know the date of their last menstrual period and/or of the at-risk sexual relations and for whom a clinical examination by a healthcare professional is possible (best practice agreement). In cases of intrauterine pregnancy of uncertain viability or of a pregnancy of unknown location, without any particular symptoms, the patient must be able to have a transvaginal ultrasound to increase the precision of the diagnosis (grade B). Various reviews of the literature on post-abortion follow-up indicate that the routine use of ultrasound during instrumental abortions should be avoided (best practice agreement). If it becomes clear immediately after the procedure that the endometrial thickness exceeds 8mm, immediate reaspiration is necessary. Ultrasound examination of the endometrium several days after an instrumental elective abortion does not appear to be relevant (grade B). An analysis of the literature similarly shows that routine ultrasound scans after medical abortions should be avoided. If a transvaginal ultrasound is performed after a medical abortion, it should take place at least two weeks afterwards (best practice agreement). The only aim of an ultrasound examination during follow-up should be to determine whether a gestational sac is present (best practice agreement). Finally, if an ultrasound is performed at any point during pre- or post-abortion care, a report should be drafted, specifying any potential gynecologic abnormalities found, but its absence must not delay the scheduling of the abortion (best practice agreement).

Medical Abortion

OBJECTIVE

This guideline reviews the evidence relating to the provision of first-trimester medical induced abortion, including patient eligibility, counselling, and consent; evidence-based regimens; and special considerations for clinicians providing medical abortion care.

INTENDED USERS

Gynaecologists, family physicians, registered nurses, midwives, residents, and other healthcare providers who currently or intend to provide pregnancy options counselling, medical abortion care, or family planning services.

TARGET POPULATION

Women with an unintended first trimester pregnancy.

EVIDENCE

Published literature was retrieved through searches of PubMed, MEDLINE, and Cochrane Library between July 2015 and November 2015 using appropriately controlled vocabulary (MeSH search terms: Induced Abortion, Medical Abortion, Mifepristone, Misoprostol, Methotrexate). Results were restricted to systematic reviews, randomized controlled trials, clinical trials, and observational studies published from June 1986 to November 2015 in English. Additionally, existing guidelines from other countries were consulted for review. A grey literature search was not required.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force for Preventive Medicine rating scale (Table 1).

BENEFITS, HARMS AND/OR COSTS

Medical abortion is safe and effective. Complications from medical abortion are rare. Access and costs will be dependent on provincial and territorial funding for combination mifepristone/misoprostol and provider availability.

SUMMARY STATEMENTS

Introduction Pre-procedure care Medical abortion regimens Providing medical abortion Post-abortion care

RECOMMENDATIONS

Introduction Pre-procedure care Medical abortion regimens Providing medical abortion Post-abortion care.

Prostaglandins for first-trimester termination

Since the 1980s, when mifepristone combined with a prostaglandin was found to be safe and effective for early abortion, many studies have refined the regimens and investigated alternatives such as methotrexate plus misoprostol, and misoprostol alone. Evidence now demonstrates that more than 200 mg of mifepristone provides no additional benefit, that vaginal misoprostol is superior to oral, especially between 7 and 9 weeks' gestation, and that misoprostol may be safely self-administered at home. Buccal and sublingual routes of administration of misoprostol also are promising. Absolute contraindications to medical abortion arise infrequently. Gastrointestinal and other side-effects occur in about one-third of women, primarily after administration of the prostaglandin. Careful assessment before and after medical abortion is essential and can be accomplished in various ways, depending on the skills of the clinician.