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Overview |
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Ultrasound is a common prenatal screening test which gives a picture of the baby in the uterus by using sound waves. These sound waves are passed through the woman’s abdomen and bounce off maternal and fetal structures to make a picture on the monitoring screen. In an ultrasound picture, bone looks white and fluid looks black. Show me an example of an ultrasound picture.
Ultrasound is helpful in giving some important information about the growth and development of the baby. In early pregnancy (8-12 weeks) ultrasound can be used to find a normal heartbeat and to measure the baby to see how far along the pregnancy is. At 18 weeks gestation, a detailed ultrasound is recommended to look for structural problems in the baby and to see if the baby is growing normally. There are no known risks associated with ultrasound.
Tell me more about ultrasound. |
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High resolution serial ultrasound examinations are indicated when chromosomal mosaicism is detected on chorionic villus sampling or amniocentesis, in order to evaluate possible concerns with the development of the baby (Hahnemann & Vejerslev, 1997). The findings of fetal malformation or severe growth retardation (IUGR) would be considered evidence of fetal involvement (Phillips et al, 1996). If mosaicism is thought to be confined to the placenta, fetal surveillance through out the pregnancy is often recommended. Normal ultrasounds are very reassuring.
When chromosomal mosaicism is found on CVS involving the sex chromosomes, polyploidy, a marker chromosome, a structural rearrangement or the uncommon trisomies (those excluding chromosomes 13, 18 and 21) the patient can be reassured if results of the amniocentesis and serial detailed ultrasound exams are normal (Phillips et al, 1996). However, there are limitations to what can be detected on ultrasound and for that reason a normal ultrasound reduces rather than eliminates the chance of concerns with the pregnancy.
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