What does a detailed fetal ultrasound assess, and does it show every anomaly? When is Doppler ultrasound requested, and is a home Doppler device the same?
A detailed fetal ultrasound is an ultrasound assessment, in mid-pregnancy, in which the development of the baby's organs and structures, the placenta, the amount of fluid and growth are systematically examined. Doppler, on the other hand, is an ultrasound method in which blood flow is assessed separately in particular situations, and it is not done routinely in every pregnancy. Neither method shows every problem: no ultrasound can detect all anomalies, and a normal finding is not a definite assurance. The word "Doppler" is also used for heart-listening devices used at home; these devices do not take the place of a medical Doppler ultrasound. If you notice a decrease or change in your baby's movements, the ultrasound having come out entirely normal is no reason to postpone seeking care.
Which structures are assessed on a detailed fetal ultrasound?
The anomaly-screening ultrasound of the second trimester assesses the bones, heart, brain, spinal cord, face, kidneys and abdominal region; the baby's growth, the placenta and blood flow to the uterus are also checked. This scope of examination may be applied differently from centre to centre and from doctor to doctor.
Are routine screening and detailed assessment the same thing?
In Turkey, the terms "detailed ultrasound", "second-level ultrasound", "anomaly screening" and "organ screening" can be used with different meanings. In some health systems, anomaly screening in the second trimester is offered to pregnant women on an optional basis. In other contexts, the term "detailed fetal anatomical ultrasound" describes a more comprehensive assessment designed for pregnancies with an increased risk of fetal anomaly. That is, the same word can describe a different examination depending on the country and the centre. You can ask your doctor which examination is being recommended to you and why it is requested.
For whom can a detailed assessment be recommended?
A detailed assessment can be considered in a situation of risk or suspicion. In which situations it is requested varies with the person and the doctor; the doctor determines this according to your history, earlier ultrasound findings and general state of health. Its being requested does not on its own mean there is a problem.
Can a detailed ultrasound show all anomalies?
It is clearly known that anomaly screening will not find all conditions. Some problems cannot be seen on ultrasound in pregnancy, and some may appear later. For this reason the statement "everything is normal on ultrasound" is not a promise that the baby will be healthy. If a new symptom appears after a normal ultrasound too, you need to seek care without waiting for the appointment.
If the image is not sufficient, is a repeat ultrasound needed?
For technical reasons some structures may not be sufficiently imaged. In this case your doctor may request a follow-up ultrasound; a new appointment being suggested if a clear image cannot be obtained is usual. A repeat look does not on its own mean that there is a problem.
What is Doppler ultrasound, and what is looked at?
Doppler ultrasound is the assessment of blood flow with ultrasound; the form of imaging in which the flow is shown with colour is called colour Doppler. The flow in the placenta, the umbilical cord and the baby's vessels can be examined. The aim is to obtain additional information on how the blood circulation of the placenta and the baby is working.
Is Doppler ultrasound done for everyone?
No. Research done concludes that the benefit of routine umbilical artery Doppler in low-risk or unselected pregnancies, for the mother or the baby, cannot be shown with certainty. Whether Doppler will be done is determined by your doctor according to whether there is a risk factor or a suspicion.
What does "Doppler is abnormal" mean?
A Doppler result being reported as "abnormal" is not a diagnosis on its own. An abnormal result may affect referral to a maternal–fetal medicine specialist and the monitoring plan. The doctor who follows you discusses with you what the result means for your pregnancy, what monitoring is needed and the next step.
Is medical Doppler the same as a heart-listening device at home?
In pregnancy the same word can occur in two different contexts.
- Medical Doppler ultrasound: The assessment, by ultrasound done on the doctor's decision, of blood flow in the placenta, the cord and the baby's vessels.
- A "fetal doppler" device used at home: Home-type devices sold for listening to the heartbeat; they are not the same thing as a medical Doppler ultrasound. It is recommended that home heartbeat devices not be relied on. Hearing a sound with the device is no reason to postpone seeking care.
Is ultrasound safe in pregnancy?
Ultrasound in pregnancy is an examination that is generally regarded as safe. Research done supports this view; on the other hand, it states the absence of large randomised studies as a limitation and recommends, as a principle, that exposure be kept as low as possible (ALARA). That is, there is not an absolute assurance about the safety of ultrasound, but a general acceptance based on the data available. When and for how long Doppler will be used is determined by your doctor according to the indication.
What happens after the result?
If the findings are at the expected level, the monitoring plan continues. If there is an uncertain or unusual finding, an additional ultrasound or tests such as amniocentesis and chorionic villus sampling may be recommended. In some situations additional imaging methods may also be considered; your doctor determines their place and necessity. You can ask for the results to be explained to you in plain language and for the reason for each step.
How can you prepare for the consultation, and what can you ask your doctor?
- Ask whether the examination recommended to you is a routine anomaly screening or a more comprehensive assessment.
- Bring your earlier ultrasound reports and your notes on the pregnancy.
- If Doppler has been requested, find out the reason and how the result will affect monitoring.
- Ask how a follow-up is planned if the image is not sufficient.
- If the result is unusual, find out who will meet with you at the next stage and which options may be discussed.
Frequently Asked Questions
My baby has come out small and Doppler is being requested; what does this mean?
Uterine artery Doppler may be recommended in those with a higher likelihood of the baby being small; this examination shows blood flow to the placenta, is generally done together with the routine anomaly screening, and its result guides the frequency of additional growth ultrasounds. Umbilical artery Doppler, which may be recommended if the baby is thought to be small or not growing, measures blood flow in the umbilical cord. Having come out small is not a diagnosis on its own; your doctor assesses the cause and the monitoring plan.
How many times a day is it normal for the baby to move?
There is no particular number of movements regarded as normal, and there is not enough evidence to recommend a movement chart routinely. What matters is that you know your own baby's usual pattern of movement and that, when you notice a change or decrease in this pattern, you tell your health professional without delay.
I have not decided to have the anomaly screening; can I change my mind later?
Yes. Screening is optional; even if you have declined it, you can ask your health professional if you change your mind later. Before deciding, it is useful to ask what the examination can and cannot show.
Does a normal detailed ultrasound rule out all problems?
No. Some problems cannot be seen on ultrasound or may appear later. A normal finding is not a definite assurance that the baby will be healthy.
Does being called back because the image was not sufficient show that a problem was found?
No. For technical reasons some structures may not be sufficiently imaged. A follow-up ultrasound being requested does not on its own mean that there is a problem.
Is Doppler needed routinely in every pregnancy?
No. The benefit of routine umbilical artery Doppler in low-risk or unselected pregnancies has not been shown with certainty. The need is determined by risk or suspicion.
What does colour Doppler show?
It is the form of ultrasound imaging in which blood flow is shown with colour. The flow in the placenta, the umbilical cord and the baby's vessels can be assessed.
Is an abnormal Doppler result a diagnosis on its own?
No. The result may affect referral to a specialist and the monitoring plan. The doctor who follows you will explain what it means for you and the next step.
Does a heart-listening device at home take the place of a medical Doppler ultrasound?
No. It is not the same examination. It is recommended that home-type devices not be relied on; hearing a sound is no reason to postpone seeking the necessary healthcare.
The ultrasound was normal; if my baby's movements decrease, can I wait?
No. Tell your health professional about a decrease or change in movements without delay. An earlier normal ultrasound is no grounds for postponing seeking care.
Does a detailed assessment being requested necessarily show that there is a problem?
No. The request may rest on your history, earlier findings or risk assessment. You can ask your doctor why the examination is being recommended.
Can an additional test be discussed after an uncertain or unusual result?
Yes. Options such as an additional ultrasound, amniocentesis or chorionic villus sampling may be considered. Your doctor determines the necessity according to the finding and the monitoring plan.
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