skip to main content

Expert Witness: Spotlight on Third Trimester Scanning

Foetal scanning during pregnancy is a non-invasive diagnostic procedure that uses ultrasound technology to create images of the developing fetus. These scans can help monitor the growth and development of the fetus and detect any potential problems. While most foetal scans are done during the second trimester, there are instances where a third trimester scan may be necessary during the final weeks of pregnancy.

Third trimester sonography is typically performed between 24 and 40 weeks of gestation and is becoming increasingly popular as it can provide valuable information to healthcare providers and expectant parents about the well-being of the baby. Transabdominal ultrasound scans can provide insight into foetal anatomy and growth/biometry, foetal presentation, foetal anomalies, gestational age, amniotic fluid volume, placental location, and umbilical artery Doppler studies.

Scans provide an opportunity to conduct a foetal structural survey for congenital abnormalities, which may be missed at the second trimester scan or new and late-developing pathology. Different types of third-trimester scans may be performed depending on the specific needs of the mother and baby. These include:

Growth scans are used to measure the size of the baby and to check that they are growing at a normal rate. It can also provide information about the amount of amniotic fluid, the position and health of the placenta, and the blood flow to the baby.

Doppler ultrasound scans are used to measure blood flow in the umbilical cord and other blood vessels in the baby's body. It can help to identify any problems with blood flow that may be affecting growth or well-being.

There has been growing interest in increasing the number of third trimester scans in recent years, as research has suggested that they can help to identify potential health concerns in the fetus that may require further intervention. A growth in high-risk pregnancies, which could be due to a rise in the average maternal age, or the increased presence of predisposed conditions such as obesity or diabetes, also raises the need to offer scans to a wider number of expectant mothers.

Saving Babies Lives Care Bundles.

An initiative called Saving Babies’ Lives Care Bundle was launched by the Secretary of State for Health in 2014 with the initial target of halving the rate of stillbirths and early neonatal deaths by 2025. The focus of version two (SBLCBv2) promotes 5 key areas:

  • Reducing smoking when pregnant.
  • Closer monitoring of foetal growth restriction (FGR), which signals a baby is smaller and lighter than it should be at a certain stage of pregnancy.
  • Increasing awareness of foetal movement such as kicks, which are a sign the blood flow through the umbilical cord is as it should be, and a baby is receiving sufficient levels of oxygen and nutrients before birth.
  • Enhanced foetal monitoring during labour.
  • Reducing the number of preterm births by raising awareness of the key contributing factors

Data are available to show that rates fell by as much as 20% at maternity units where the care bundle was present between its launch in 2016 and April 2017. Version 2 was published in 2019 with a continued focus on reducing the rate of stillbirths, which is a strategic imperative for the NHS. Despite falling to its lowest level in 20 years, the target is to halve the rate of stillbirths from 4.7 per thousand to 2.3 per thousand by 2030.

The importance of third trimester scans.

Early detection of foetal abnormalities can lead to better outcomes for both mother and baby and can allow for appropriate interventions and treatment to be put in place. In some cases, early detection can even save the baby's life. For example, if a baby is diagnosed with a heart defect in utero, doctors can plan for the baby's delivery and ensure that the baby receives the appropriate medical care immediately after birth.

Third trimester scanning provides detailed information about the growth and development of the fetus, including the size and position of the baby, the amount of amniotic fluid present, and the function of the placenta. This information can help healthcare providers to identify potential health concerns, such as reduced or increased amniotic fluid volume, FGR, or placental insufficiency, and take appropriate steps to manage these issues.

Scans can also detect structural abnormalities in the fetus, such as congenital heart defects or neural tube defects, that may require further investigation or intervention. This can help to ensure that the baby receives appropriate care and treatment after birth and may also allow expectant parents to prepare emotionally and practically for any challenges that may lie ahead.

In addition to the potential health benefits, an increase in third-trimester scans can also have a positive impact on the mental health of expectant mothers. Pregnancy can be a time of great anxiety, particularly for first-time mothers. Knowing that their baby is healthy and developing normally can help to alleviate some of that anxiety and allow mothers to enjoy their pregnancy more fully.

Current practices for exploring foetal scans in the third trimester vary depending on the healthcare provider and the individual case. However, it is generally recommended that all pregnant women receive regular prenatal care, including routine ultrasounds and foetal monitoring. Between 2016 and 2018, demand for third trimester scans increased by 28%, illustrating the success of the care bundle in raising awareness.

The impacts of increased demand.

One potential concern with an increase in third-trimester scans is the availability of trained healthcare professionals to perform them. To maintain the service, midwives are increasingly being trained to perform these scans, which can help to expand access to this important screening tool. However, despite being trained sonographers, they are not always trained in the full PGCert Ultrasound that performs dating and anomaly scans and so the impacts of midwives performing these scans may vary depending on their level of training and expertise.

Midwives are often the primary healthcare providers for pregnant women, particularly in areas with limited access to obstetricians or other specialists. By completing the appropriate professional training, in addition to delivering midwifery expertise, midwife-sonographers can perform end-to-end oversight from triage to post-scan management. This delivers continuity of care and presents a more cost-effective approach for healthcare providers.

Trained midwives can offer a more personalised and holistic approach to prenatal care and reduce the number of appointments to enhance the overall experience. Midwives may have more time to spend with patients and can therefore provide emotional support and counselling during the scan.

However, if a midwife is not properly trained or experienced in performing foetal scans, there is a risk that they may miss important information or misinterpret the results, which could lead to missed diagnoses or unnecessary interventions. To address these concerns, it is important to ensure that midwives receive adequate training and support to perform third trimester scans safely and effectively. Perhaps they could undertake additional training in foetal anatomy and physiology, as well as receive ongoing supervision and support from experienced healthcare professionals.

Understanding the risks

Not all complications that may arise during pregnancy can be identified by a third-trimester scan, and it is possible for a scan to miss or incorrectly identify a health concern. While exploring foetal scans in the third trimester can be essential, there are limitations to what can be detected and prevented. The BMI of the mother can impact scan accuracy, as can the position of the baby. Some congenital anomalies or genetic abnormalities may not be identified until after birth, and some risks may be unavoidable despite the best efforts of healthcare providers.

In the event of failings or errors in the scan, claims may be made against the healthcare provider or hospital. These claims may be related to issues such as misdiagnosis of a health concern, failure to detect a structural abnormality or failure to provide appropriate advice and guidance to expectant parents.

In cases where potential risk is identified, recommendations for further testing, such as amniocentesis or ultrasound, or interventions, such as early delivery or caesarean section may be made. These may lead to further ongoing complications and if later questioned can expose healthcare providers to potential litigation.

The role of an expert witness

Bush & Co can provide expert witness services to assist with clinical negligence proceedings related to several clinical specialisms including nursing and midwifery, physiotherapy, and catastrophic injury.

Sarah Bonner is a specialist third trimester midwife sonographer and expert witness working in one of England’s largest NHS Trusts. Sarah highlights the importance of expert witnesses:

“Expert witnesses play a crucial role in cases involving foetal scans in the third trimester. We offer an objective opinion based on the available evidence and our testimony can provide clarity and insight into the complex medical issues in a way that is easily understood by the court.

"We examine scans taken throughout the pregnancy for any abnormalities or concerns that may have been identified and analyse medical records to assess the quality of medical care provided. In addition, other areas are evaluated to determine whether a thorough risk assessment was carried out, or whether NICE or Trust guidelines were followed.”

Through their expertise, an expert witness can help to establish whether the medical professionals involved acted in accordance with the appropriate standard of care. This is especially important when it comes to foetal monitoring and interpreting ultrasound scans, where mistakes can have devastating long-term consequences.