Detailed Morphology Ultrasound …
A second trimester morphology ultrasound is performed in the middle part of the pregnancy, usually between 18 and 23 weeks gestation.
The purpose of this scan is:
– To confirm a viable (alive) intrauterine (within the womb) pregnancy. This is achieved by demonstrating a beating fetal (baby) heart.
– To date the pregnancy if this happens to be your first scan in your pregnancy. Although this is not as good as dating by an early pregnancy scan, it still has an accuracy of about 7 days.
– To diagnose multiple pregnancies if this is our first scan. Diagnosing twins or higher order multiple pregnancies early helps appropriate pregnancy planning.
– To provide a detailed anatomical survey of the developing baby. A number of major structural anomalies can be seen at this stage.
– To describe the position of the placenta (afterbirth).
Most of the times, the scan is done transabdominally. This means the probe that produces and receives ultrasound waves touches your lower abdomen (tummy) and allow us to get views of the uterus (womb). Special gel is used to improve contact between the probe and your tummy.
Very rarely transvaginal (internal) scan is needed. This means that a special probe is inserted in your vagina. By approaching the baby from a different angle some structures may be seen better this way. The doctor will explain to you the type of scan that needs to be done and a chaperone will be in the room during internal scans.
Having an ultrasound scan should not be painful. If in any case you feel uncomfortable, let the doctor know. A full bladder helps with transabdominal scans as it pushes your womb upwards and at the same time pushes the bowel out of the way creating good window to look at your baby.
Most scans are happy experiences but sometimes problems are either seen or suspected. At this stage of the pregnancy, possible problems that can be picked up are:
– Suspicion or evidence of a structural anomaly (problems relating to how the baby has developed). The doctor will explain the findings to you and depending on the problem, explain what are the implications for your pregnancy and the baby. In some occasions, further tests may be needed to clarify the diagnosis.
– A low lying placenta. Although this is not a problem at this stage of the pregnancy further scans will be needed later in pregnancy to confirm that the placenta has moved out of the way. Ask the doctor to provide you with the relevant information sheet.
At the end of the scan, you will be given a computerized report which will describe the structures seen and if there are any particular difficulties during the scan. At this stage, a large number of structural problems that a baby may have can be picked up. Ultrasound can usually provide information as to how various organs are put together and not how well they function. Please note that scans are not foolproof. They do not show all the anomalies and in some occasions, anomalies can be missed. A normal scan is not a guarantee of the delivery of a perfect baby.