Do We Need More Scans in the Third Trimester?
Ultrasounds are a favorite part of pregnancy for many expecting parents. These powerful, yet brief, glimpses of the womb can offer reassurance and anticipation. They are also often the first time parents see their growing child. Two ultrasounds are part of standard prenatal care in low-risk pregnancies: one in the first trimester to confirm the pregnancy and establish dates, and another around 20 weeks to assess the baby’s anatomy. However, Third-Trimester Ultrasound May Save Lives, prompting a closer look at whether more late-pregnancy scans should be considered.
[ez-toc]
The 20-week ultrasound is a significant milestone. The 20-week scan is a milestone for most parents. They can learn the sex of their child, view their baby’s face and limbs, and receive feedback about fetal growth. After that scan, if everything appears normal, there are no further scans scheduled, unless a medical issue is present. This means that many women enter the last weeks of their pregnancy without having another scan.
A groundbreaking study from Cambridge University has now questioned this long-standing practice. The researchers are calling for an additional scan in the third trimester–specifically around 36 weeks–as a potential life-saving measure.
Why Should You Consider an Ultrasound in the Third Trimester?
The study published in PLOS Medicine presents convincing data suggesting that a single additional scan during the late stages could reduce complications. This is especially true for those related to breech deliveries. The study also suggests that the scan may lead to fewer emergency c-sections and reduce perinatal death.
These claims aren’t just speculative. Researchers analyzed thousands of births to find that routine third-trimester ultrasounds can help detect babies in breech positions well before labour starts, allowing doctors to intervene at an early stage.
This recommendation could be a significant shift in the maternity care system, particularly in countries where scans in the third trimester are not performed routinely for low-risk pregnancies.
What is a Breech Birth Exactly?
In the last weeks of pregnancy, many babies are in a position where they lie on their backs, ready to be delivered. Cephalic is the ideal position for vaginal delivery. In approximately 3-4% of full-term pregnancies, the baby remains in a breech position, meaning that their feet or bottom is positioned so they come out first.
Breech births can be extremely complicated, and they are associated with higher risks for both mother and baby. While vaginal births of breech babies are possible in the right circumstances, they carry a greater risk of complications, such as cord prolapses, head entrapment or prolonged labour. Most breech births are planned cesareans.
The key to breech presentation detection is to detect it before the start of labour. Many times, a breech presentation is not detected until labour has already begun. By then, the options are limited, and an emergency C-section may be required.
What the Research Says
The Cambridge team believes that if all pregnant women were offered a routine ultrasonography at 36 weeks, it could detect thousands of breech-born babies before labour begins. Their findings are:
- It is possible to anticipate and manage up to 15,000 breech deliveries.
- About 4,004 emergency cesareans can be avoided.
- In the UK alone, it is possible to prevent up to 8 infant deaths each year.
The numbers don’t just represent statistics, they are real births and real families. They also represent opportunities for improvement. Healthcare providers can perform external cephalic version (ECV) to manually turn breech babies into a down position by identifying them in advance.
ECV does not work in all cases, but it is effective in approximately 50% and reduces the chances of a breech delivery.
Financial and Public Health Gains
The authors of the study also present a compelling economic argument. Emergency sections are resource-intensive: they require additional staff, longer hospital stays, and more time for recovery. Planned C-sections can be performed in a more controlled and less stressful environment.
Researchers argue that identifying breech infants earlier could reduce costs by significant amounts. Even if ECV can’t be done in every case, knowing the breech baby position allows for better planning. This will lead to a safer outcome for mother and child.
The third-trimester scans can also identify issues like:
- Placenta abnormalities (such as placenta previa and placental abruption risk)
- The amniotic fluid level is low or high
- Intrauterine growth restriction (IUGR)
- Macrosomia is a term used to describe an unusually large baby.
The late-term ultrasound can be used to detect these conditions, which may need adjustments to your birth plan.
Some People Disagree About Emotional Benefits
The Cambridge study is a compelling case for the benefits of additional third-trimester ultrasonography from both a medical as well as a logistical standpoint. However, another team in the Netherlands investigated whether the extra ultrasounds would have any emotional and psychological advantages for expectant mothers.
The study involved more than 1,200 women who were low-risk and under midwife care. It looked at whether additional scans helped reduce anxiety during pregnancy or improved mother-to-baby bonding.
Two groups of women were divided: One group received the two standard ultrasounds and the other two additional scans in the third trimester, one between 28-30 weeks and the second at 34-36 weeks.
Participants complete psychological questionnaires to:
- Pregnancy anxiety
- Maternal attachment towards their unborn child
The results were surprising. They showed that there was no emotional benefit to the extra scans.
The Emotional Study’s Findings
Here is a closer look at what the researchers found:
- The Pregnancy Related Anxiety Questionnaire (which measures anxiety levels) was nearly identical in both groups.
- The Maternal Antenatal Attachment Scale also did not show any significant differences in bonding scores.
Conclusion? In general, more scans did not equal greater peace of mind. Most women found that a third-trimester ultrasound did not improve their emotional attachment to the baby or reduce stress during pregnancy.
There were some exceptions. Women who began the study with greater levels of emotional distress or depression did seem to benefit from the additional ultrasounds. Women who were highly satisfied with their ultrasound experience also showed improved emotional outcomes.
So while the added scan may not be a universal emotional booster, it could be a helpful tool for certain subgroups–particularly those dealing with anxiety or prenatal depression.
The Study Provides Additional Insights
The ultrasounds were not without value, even though their emotional impact was minimal. The 487 women who underwent third-trimester ultrasounds included:
- 11.1% of respondents had found evidence that growth issues were present, including:
- IUGR (fetal Growth Restriction
- Macrosomia is a term used to describe an unusually large baby.
- Low levels of amniotic fluid
These results show that late-term routine scans are still a crucial tool in detecting subtle complications, even if they do not manifest symptoms. Early detection can lead to proactive management and improve outcomes.
Should Third-trimester Ultrasounds be Routine?
The answer to this question depends on the balance you strike between medical costs, emotional impact, and benefits.
Clinically, there is increasing evidence that at least one scan should be performed late in pregnancy. This relatively low-cost, low-risk procedure can help prevent serious complications and reduce the need for emergency interventions. It may even save lives.
The emotional benefit is not universal, but for women who are dealing with anxiety, depression,o n or trauma during pregnancy, seeing their child on screen could provide a sense of relief or reassurance.
As more data become available, many healthcare providers are re-evaluating policies. In countries with strong public healthcare systems, third-trimester ultrasounds may be incorporated into prenatal care as a standard for all pregnant women and not just high-risk ones.
What Does This Mean to You
This is an important conversation to have with your doctor if you are pregnant or plan to become pregnant. You can still ask if a third-trimester ultrasound would be helpful for you, even if you are pregnant and your pregnancy is going well.
Why your doctor may recommend a stent
- You haven’t confirmed that your baby is head-down
- You have experienced abnormal fetal movements
- If you have a record of complicated or breech deliveries
- If you have gestational diabetes, high blood pressure, or other conditions that affect your health
- Want extra peace of mind when you go into labor?
Asking questions and advocating for yourself is always acceptable. Many providers are willing to talk about options, particularly when they have research to back them up.
Final Thoughts
The ultrasound has evolved from a simple medical tool to a much more sophisticated one. Many women consider them an important part of their pregnancy journey. New science shows that one last scan during the final stages of pregnancy can offer much more than a cute photo. It could provide critical insights, reduce complications, and even save lives.
The clinical data are becoming increasingly difficult to ignore, even though the emotional benefits can vary. Re-examining the role of ultrasounds in the third trimester could lead to safer and smarter prenatal care.
Consult your provider and ask questions. Make the decision that feels right to you.
