Ultrasound technology has revolutionised prenatal care. It is offering expectant parents and healthcare providers a window into the developing pregnancy. From confirming viability in the early stages to monitoring fetal development throughout, the ultrasound remains a cornerstone of pregnancy care. In the third trimester, its role becomes particularly crucial. Both for identifying potential complications and preparing for a safe delivery. So the importance of routine third-trimester ultrasound scans can be underestimated. Here is why.
Detecting Breech Presentation
One of the most significant benefits of a third-trimester ultrasound is detecting breech presentation. This is where the baby is positioned feet or buttocks first, instead of headfirst. Breech deliveries can pose substantial risks to both the baby and the birthing parent. Often they are necessitating a planned caesarean section (C-section) for safety. Studies indicate that routine third-trimester ultrasound scans can reduce undetected breech pregnancies by up to 71%. Which is a very high percentage. They are offering ample time for interventions such as external cephalic version (ECV), where a doctor attempts to manually turn the baby to a headfirst position. If ECV is unsuccessful or not suitable, planned C-sections can be arranged to avoid emergency scenarios during labour.
Dr Enam Abood, a lead physician with the Walk In Clinic in London, highlights this point: “Routine scans in late pregnancy can identify breech presentations that might otherwise go unnoticed until labour. This allows us to intervene proactively, significantly improving outcomes for both mother and baby”.
Monitoring Fetal Growth
A third-trimester scan plays a vital role in assessing fetal growth and identifying potential issues such as growth restrictions. These are divided to small for gestational age, or macrosomia, which is excessive fetal growth. Both conditions carry unique risks during labour. Growth restrictions may indicate placental insufficiency, potentially leading to complications like fetal distress. Conversely, macrosomia can increase the likelihood of labour complications, such as shoulder dystocia. Early detection enables healthcare providers to develop tailored management plans, which may include increased monitoring, nutritional advice, or scheduling an induction or C-section when necessary.
Amniotic fluid levels are key. They provide important insights into the baby’s well-being. A third-trimester scan can identify abnormalities such as low fluid levels (oligohydramnios), which may suggest fetal distress, or high fluid levels (polyhydramnios), potentially linked to gestational diabetes or congenital anomalies. By detecting these issues early, healthcare teams can implement interventions to reduce risks, ensuring the best possible outcome for the baby.
Placental Position & Function
The position and health of the placenta are essential factors in determining a safe delivery. Third-trimester ultrasounds can confirm whether the placenta has migrated away from the cervix in cases of earlier placenta previa. it can also identify signs of placental insufficiency, which could affect the baby’s nutrition and oxygenation. If complications are detected, this allows the medical team to take pre-emptive measures, such as recommending early delivery or increased monitoring.
In the final weeks of pregnancy, ultrasound can provide valuable information about the baby’s overall health. By examining fetal movement, tone, breathing patterns, and amniotic fluid levels, clinicians can calculate a biophysical profile score. A low score may prompt additional monitoring or interventions to safeguard the baby’s health. A comprehensive assessment ensures that pregnancies are monitored, especially closely in cases where complications are suspected.
Psychological Reassurance for Parents
Being able to view their baby at this period, a third-trimester scan, can be very reassuring for many expectant parents. It is especially important in cases where there were complications or losses in prior pregnancies. Knowing the baby is well on its journey of development and understanding the expected delivery time might help decrease anxiety and make the parents more attached and involved with the pregnancy.
Routine third-trimester ultrasound gives very important information on the position of the baby, and can prepare the healthcare team for his delivery. For example, in the case of a breech presentation, an ECV can be attempted, or a planned C-section can be scheduled. If growth concerns or placental issues are noted, induction of labour can be timed so as to maximise safety for both the baby and the birthing parent.
There is continued debate in the medical community as to whether third-trimester ultrasound should be routine for all pregnancies or offered selectively in pregnancies with specific risk factors. A Dutch study, the IRIS study, showed no obvious benefit of routine scans in low-risk pregnancies in reducing adverse perinatal outcomes. The value of such scans in specific situations, such as the detection of breech presentation, however, is not in question. Opponents argue that routine scans could cause unnecessary interventions, and raise healthcare costs, while proponents emphasize their potential for the early identification of complications to improve outcomes.
Emerging Trends in Pregnancy Health
The role of third-trimester ultrasounds aligns with broader trends in prenatal care, including a focus on personalising care and embracing technology for better outcomes. The growing emphasis on maternal health equity and access ensures that advanced diagnostic tools are becoming more widely available, even in resource-limited settings. Additionally, the development of more portable and affordable ultrasound devices is helping expand access to this critical technology.
The future of prenatal care looks promising, with innovations in maternal health technology and diagnostics continuing to evolve. Companies such as GE Healthcare and Philips are investing in state-of-the-art ultrasound systems to improve imaging quality and accessibility. As Dr Williams explains, “With advancements in technology, routine ultrasounds can be delivered more effectively, ensuring that every pregnancy is monitored with the highest standard of care.”
Routine third-trimester ultrasounds represent a vital tool in modern obstetric care. They are helping to provide crucial insights into fetal health, placental function and delivery planning. While debates around routine versus selective scanning persist, there is no denying the benefits these scans offer. Specially in detecting potential complications and preparing for safer deliveries. As prenatal care continues to evolve these ultrasounds are likely to remain a cornerstone of pregnancy management. For many years to come.