|What Is An Anatomy Scan?
Also known as an anomaly scan or anatomic survey, an anatomy scan is the most extensive ultrasound exam carried out on the fetus during pregnancy. It is performed between weeks 18 and 22 and is the one
|What Is An Anatomy Scan?
Also known as an anomaly scan or anatomic survey, an anatomy scan is the most extensive ultrasound exam carried out on the fetus during pregnancy. It is performed between weeks 18 and 22 and is the one most people are referring to when they talk about their routine pregnancy scan or their 20 week scan. The baby's gender can usually be reliably revealed in this scan (see, how accurate is a scan at predicting gender?). It is performed as an abdominal scan (a transvaginal scan, where a probe inserted into the vagina is only performed if there is a risk of premature birth). There has been some medical debate as to whether an anatomy test should be routinely performed, particularly in cases where a termination is not an option. Yet, studies consistently show that infant mortality rates are lower when it is performed. Additionally, pregnancy complications are reduced, particularly where placenta problems have been identified and corrected.
Benefits Of Anatomy Scan
Advance Warning System
If doctors discover a serious birth defect, the baby has a better chance of survival if the problem is detected before birth. This is because it allows the medical team to prepare for the birth and ensures the birth will take place at a hospital medically equipped to take care of the newborn. For example, if the baby has a heart defect, being born in a hospital staffed with pediatric cardiologists can mean the difference between life and death.
Treatments Before Birth
Most birth defects can only be treated once the baby is born. In some cases however, temporary interventions can be performed while the baby is still in the womb (in utero). For example, if the baby's bladder or kidneys are blocked, doctors can make a small hole in the uterus and insert a tiny surgical tool called a fetoscope. With the fetoscope, tubes or shunts can be placed in the bladder or kidneys to temporarily free up the area. Most in utero treatments are only temporary and further surgery will be required after birth.
Soft markers are non-definitive, subtle and usually harmless physical signs that your baby has Down syndrome. If they are found, you will be told that there is a high risk that your baby has Down's and you may be offered more invasive testing - namely an amniocentesis or chorionic villus sampling (CVS test).
What An Anatomy Scan Can Detect
||Percentage of cases detected
|Spina bifida (open spinal cord)
|Anencephaly (top of the head missing)
|Hydrocephalus (fluid in the brain)
|Major heart problems (congenital heart defects)
|Diaphragmatic hernia (defect in the muscle which separates the chest and the abdomen)
|Exomphalos/gastoschisis (defects of the abdomen)
|| 90 percent
|Major kidney problems (either missing or abnormal kidneys)
|| 85 percent
|Major limb abnormalities: (missing bones or very short limbs)
||About 40 percent
What Happens During The Scan?
An anatomy scan takes much longer than any other type of pregnancy scan - it usually lasts 40 minutes but can take longer if the baby is not cooperating by lying in the correct position. You may be asked to jiggle your belly or take a short walk to get junior to cooperate. During the procedure gel is smeared to the belly area to ensure good contact between the skin and transducer (the device that emits ultrasonic waves). The transducer is placed on the belly and is rolled back and forth while internal images can be seen on a monitor next to the technician. In earlier scans the son