Abortion complications – new official statistics

Independent public health consultant, Kevin Duffy, comments on the statistics that reveal a higher percentage of abortion complications than many have been led to believe

On 23 November 2023, the Office for Health Improvement & Disparities (OHID), part of the Department of Health and Social Care (DHSC), published new official statistics reporting the rate of complications arising from abortions in England. Previous reporting from the DHSC relied solely on data gathered from the HSA4 forms that are routinely submitted by abortion providers to the Chief Medical Officer (CMO), this is known as the Abortion Notification System (ANS). Acknowledging the limitations of the ANS data when reporting abortion complications, the OHID set out to explore whether Hospital Episode Statistics (HES) could be used as a supplementary source for abortion complications data.

HSA4 forms must be submitted to the CMO within 14 days of an abortion procedure and are used to report any complications arising before the patient is discharged. This works well when the procedure is completed at the abortion facility. However, in 2021, 70% of all abortions were self-managed by women at home (52% using both mifepristone and misoprostol, and 18% using misoprostol at home after taking mifepristone at the provider’s facility).[i] In these cases, the HSA4 form would have been submitted after the early medical abortion treatment was prescribed or when the woman left the facility, and thus before self-administration of the tablets and before any complications were suffered. This is the key limitation of the ANS and why the OHID is considering supplementary use of HES data.

The Hospital Episode Statistics (HES) is a system recording details of all attendance and admissions at NHS hospitals across England. For this report, the OHID used only the data related to inpatient admissions for an abortion related complication. They explain how these records do not include, and are not conflated with, admissions for women suffering complications from a miscarriage, though they explain that some women might choose to report a miscarriage rather than admitting to having used the abortion pills, which in turn would lead to under-reporting of abortion complications.

Importantly, HES can be used to report on complications arising from an incomplete abortion, when parts of the placenta and/or embryo remain within the uterus, referred to as retained products of conception (RPOC). An incomplete abortion causes complications such as bleeding and pain, with a risk of infection, and can be treated surgically by an evacuation of retained products of conception (ERPC). The HSA4 states that an ERPC is not a complication and thus these cases are not included in the ANS.

The OHID considered data from both systems for the years 2017 to 2021. It reports the average rate of abortion complications per 1,000 abortions from each as follows:

• Abortion Notification System (ANS) – 1.5
• Hospital Episode Statistics (HES) – 18.2

It is remarkable that the HES reported rate is almost twelve times higher than that from ANS.

The HES data for 2021 shows an abortion complication rate, including incomplete abortions, of 19.3 per 1,000 abortions, a rate of almost 2%. This report only includes the cases in which the woman was admitted as an inpatient, typically for an ERPC, it does not report any women who presented with abortion complications and were treated in A&E or any other outpatient department.

Retained products of conception can be treated in one of three ways:

• Expectant management, in which the woman is told to do nothing, wait for a few days longer, giving her body a chance to deal with the problem (outpatient).
• Additional doses of misoprostol (outpatient).
• A surgical evacuation of retained products of conception (inpatient).

Commonly, each of these three treatments might be used in broadly equal numbers, often depending upon the perceived severity of bleeding/pain and on the availability of trained medical staff able to perform the ERPC and of inpatient beds. If these three treatments are used in broadly equal numbers then the 2% complication rate which relates only to inpatient treatment would translate into a roughly 6% complication rate allowing for the other two treatment paths. A 6% complication rate matches the known complication rate from other independent data, including the Royal College of Obstetricians & Gynaecologists online information for those considering an abortion.

This comparison of the abortion complications data available for reporting from the ANS and the HES is very welcome. The OHID has shown very clearly the significant gap in the reporting of abortion complications when relying solely on the HSA4 forms and the ANS. We hope that this new approach using additional data from the Hospital Episode Statistics will be quickly adopted as an official routine publication. Having taken this important first step towards assuring the completeness of abortion complications reporting, we ask the OHID to explore further how it might also include data about the visits and treatments managed at A&E and other outpatient departments.

[i] Tab ‘T2’ in the spreadsheet ‘Abortion statistics 2021: additional tables (revision)’, accessed from https://www.gov.uk/government/statistics/abortion-statistics-for-england-and-wales-2021 on 24 November 2023.