Spontaneous miscarriage is the most common complication of pregnancy and occurs in up to one-fifth of clinical pregnancies, equating to around 15,000 miscarriages each year in Ireland. Last month, the HSE published the National Miscarriage Misdiagnosis Review Report, which looked at cases of misdiagnosis of miscarriage that occurred in the past five years.
It examined instances where a wrong diagnosis of miscarriage was made and a drug or surgical treatment was recommended to a woman, and where subsequent information showed that the pregnancy was still viable.
In 2010, media reports brought wrongly diagnosed miscarriage to the attention of women around the country and, following this, maternity hospitals nationwide received 400 calls from women who had been told they had miscarried, but now feared it was a misdiagnosis.
Of these 400 women, 24 wrong diagnoses of miscarriage occurred. Some 22 of these went on to have live births. The review found that inadequate staff training and an over-reliance on ultrasound led to the 24 women being wrongly told that they had suffered a miscarriage. There had been no mandatory training in ultrasound in half of the cases examined. In the report, the 24 clinicians were described as having “significant experience” in conducting ultrasound in early pregnancy; however, only three of these reported “formal training” in early pregnancy ultrasound.
According to the HSE, the “prevalence of miscarriage misdiagnosis was small”. Professor William Ledger, Chair of the Review Group, stated that: “The 24 misdiagnoses occurred at the very early stages of pregnancy, when ultrasound diagnosis alone is unreliable, due to the risk of missing a tiny foetus or heartbeat.”
He also advised that, “over-reliance on ultrasound to diagnose a miscarriage in very early pregnancy has been repeatedly highlighted since the introduction of the technique in the 1970s, and we have made recommendations that caution against the use of ultrasound alone to detect a pregnancy before eight weeks gestation.”
On the back of the review, new clinical guidelines were developed, entitled “Ultrasound Diagnosis of Early Pregnancy Miscarriage”. Those behind the clinical guidelines were the Institute of Obstetricians and Gynaecologists at the RCPI and also the Directorate of Quality and Clinical Care at the HSE.
The purpose of the guidelines are to, “assist all healthcare professionals in the management of first trimester spontaneous miscarriage.”
Information outlined relates to the diagnosis of early pregnancy loss, defined as a loss within the first 13 weeks of pregnancy. After the review highlighted an over-reliance on ultrasound as a major part of the misdiagnosis problem, the guidelines also specifically address diagnosis of miscarriage using ultrasound.
Those behind the guidelines state they are intended to be primarily used by health personnel working in the area of early pregnancy, including obstetricians, midwife sonographers, radiographers, radiologists and GPs. It advises that, “all of the groups should be familiar with the various diagnostic tools necessary to help delineate a viable from a non-viable pregnancy.”
Current international guidelines in the UK, US, Canada, Hong Kong, New Zealand, and Australia were looked at when producing the Irish equivalent.
The updated version recommends that the medical term for pregnancy loss at less than 24 weeks should be “miscarriage”. Use of terms such as “pregnancy failure” or “incompetent cervix” should be avoided as this could “contribute to a woman’s negative self perceptions and aggravate any sense of failure, guilt and insecurity related to the miscarriage”. In addition, the recommendations state that the terms “abortion”, “an embryonic pregnancy” and “blighted ovum” should be abandoned.
The guidelines also stated that it is “important that all relevant health personnel are familiar with the chronological ultrasound features of early pregnancy”, as human error was a major factor in the numbers of misdiagnosis.
Some 13 misdiagnoses were made by registrars, six misdiagnoses were made by consultants and in five cases, misdiagnoses were made by house officers.
The clinical guidelines also advised there are, “certain ultrasound features which predict but are not diagnostic of early pregnancy failure.”
These include a foetal heart rate of less than 85 beats per minute at greater than seven weeks gestation, a small sac size relative to the embryo (difference of less than 5mm between gestation sac and crown rump length), enlarged or abnormally-shaped yolk sac and sub-chorionic haematoma. The latter leads to a pregnancy loss rate of about nine per cent. This risk appears to be increased in women older than 35 years and in pregnancies less than eight weeks gestation. The guidelines rated that any clinical interventions must be based on diagnostic and not predictive features.
In addition, the guidelines outline common pitfalls with ultrasound in early pregnancy.
The document advises healthcare professionals to exercise extreme caution regarding the last menstrual period when taking history of the patient. Up to half of women are uncertain of their dates, or have an irregular cycle, or may have just stopped the oral contraceptive pill (OCP). Furthermore, they may be lactating or may not have had a normal last period.
The guidelines state that the healthcare professional should enquire when the women had her first positive pregnancy test, which the guidelines say may be positive three days before the missed period.
According to the HSE review, faulty equipment was also culpable. The guidelines recommend that “ultrasound machines should be of good quality and should be regularly maintained, serviced and checked for safety”. It adds that records of maintenance and service should be easily discoverable. n
