Ultrasounds

FAQ

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Question:
What is a Level II ultrasounds examination?

Answer:
A level II ultrasound examination is a 'targeted' examination. This is normally undertaken at a prenatal center where there is more expertise in ultrasound scanning.

Occasions when a level 2 ultrasound is ordered include:
Suspected fetal anomaly during a level I examination, severe IUGR, elevated maternal-serum AFP, two-vessel umbilical cord detected at the level I examination, fetal cardiac arrhythmia, and exposure to drugs or chemicals in the first trimester....etc.

Detailed scanning for any congenital anomalies and growth abnormalities is done as well as the basic documentation obtained at the level I examination, which refers to:
In the first trimester,

1. documenting the location of the gestational sac.
2. documenting the crown-rump length.
3. documenting the presence or absence of fetal life.
4. evaluating the uterus (including cervix) and adnexa.
In the second and third trimester,
5. documenting fetal life, number, and presentation.
6. documenting an estimate of amniotic fluid volume.
7. documenting placental location.
8. documenting gestational age. Assessing the BPD, FL, AC and other fetal parameters.
9. documenting basic fetal anatomy (including a basic 4 chamber view of the heart, spine, stomach, kidneys, bladder, umbilical cord insertion ... etc ).

One shouldn’t dwell too much on the definitions or guidelines for a level II ultrasounds scan. In a level II scan the sonologist should try to look for and assess any abnormality present in the fetus. It is pointless to be pondering about level III or level IV scans.

ultrasounds

Question:
My wife has not had a scan during her current pregnancy. I heard that the majority of hospitals routinely perform an ultrasound scan at about 20 weeks. I wondered why this hasn’t been done in my wife's case ?

Answer:
The issue of 'Routine scans' in a 'low risk' patient is still currently being debated. I personally feel that a policy of routine scans should be implemented for every pregnancy at 18-20 weeks. Few people will deny that scans are extremely usefulness in improving gestational age dating, in the early diagnosis of fetal abnormalities, in the identification of intrauterine growth retardation and of multiple gestations.

Apparently there is a distinct difference in the attitude towards routine ultrasound screening between the Europeans and the Americans. Routine ultrasounds were started in Germany in 1980, Norway in 1985 and Iceland in 1987. Basically, the scans are used to try to date the pregnancy and to exclude the possibility of twins and detect any fetal malformations that may be present.

However in the United States, routine scans in pregnancy have been looked upon with much controversy and their cost-effectiveness and validity in improving 'quantifiable' perinatal outcome has never been firmly established. Yet those who argue for routine scanning would claim that parents have a natural desire to know if any fetal congenital anomaly is present or if there is any health compromise in the fetus. The ability to reassure parents is an important part of prenatal care.

Two significant large scale studies emerged to address the issue: the RADIUS study (Routine Antenatal Diagnostic Imaging with Ultrasound) with a cohort of 15,000 low-risk pregnancies in the United States in 1993 and the Eurofetus Study in Europe in 1997 in which 200,000 low-risk pregnant women in 60 hospitals had obstetric ultrasound examinations performed in centers proficient in prenatal diagnosis. A 61% overall detection rate of structural anomalies in the Eurofetus study was in sharp contrast with the 35% overall detection rate in the RADIUS study.

In June 1997, a conference was held at The Rockefeller University in New York City in order to address the conflicting data and conflicting opinions on this topic. More than 150 scientists and clinicians took part in the meeting, with extremely informative presentations and discussions.

The following conclusion was reached:
" In summary we have attempted to combine comprehensive state-of-the-art guides on the routine obstetric ultrasound issue. Our conclusion is that obstetric ultrasounds are allowable for all pregnancies, but only if its done in a qualified manner. Although there is scientific and economic concerns about our conclusion, we would say that, at a minimum there’s an ethical obligation to present the choice of an 18-22 week routine obstetric ultrasound exam in clinical centers in which quality ultrasounds are available. We hope that our efforts will move public policy in this direction and encourage further discourse on this most important topic in contemporary obstetrics."

The cost of healthcare could greatly increase in a setting with routine scanning. It is likely that the consideration of such cost-effectiveness is of concern at the hospital your wife is attending. For individual private patients I have no hesitation in routinely ordering a scan at 18-20 weeks.

It should also be remembered that it is possible to miss over half of significant abnormalities in a fetus during a routine scan. This can give parents a false sense of security. However, this does not mean the situation would be improved without this scan.

Great Ultrasounds Inquiries

Question:
Are there any advantages of early screening scans in pregnancy (12 weeks) to detect anomalies, or is it better to wait for the regular scan at 18-20 week.?

Answer:
Screening scans at around 11-14 weeks are becoming almost routine. They are used mainly to look for an increased nuchal translucency and absent fetal nasal bone for the detection of chromosomal anomalies. With the identification of an absent nasal bone and a thickened nuchal translucency in the fetus the possibility of Trisomy 21 is greatly increased. In recent times, the presence of triscuspid regurgitation is also observed to increase the ultrasounds detection rate.

The screening is normally performed with an abdominal rather than a vaginal scan. A further scan at about 18 to 20 weeks will still be required for such anomalies as cardiac, spinal, intracranial and facial abnormalities.

What is an ultrasound?

An ultrasound (also called a sonogram) is a noninvasive diagnostic examination that makes uses of sound waves to create visual images of your baby, placenta, and uterus, along with other pelvic organs. It enables your healthcare practitioner to obtain valuable information about the progress of your pregnancy and your baby's health.

During the ultrasound, the technician (sonographer) transmits high-frequency sound waves that pass through your uterus and bounce off your baby. The echoing sounds are translated into video images that reveal your baby's shape, position, and movements.

The series of television-monitor images is referred to as a sonogram. The words ultrasound and sonogram are often used to mean the same thing. The Doppler that is used to hear a baby’s heartbeat in the womb also uses ultrasound waves.

The majority of pregnant women have a routine ultrasounds when they are between 16 and 20 weeks pregnant. However you may have a scan as early as 4 or 5 weeks or any time after that if a problem is suspected. Many people look forward to their midpregnancy ultrasound as it provides them with a first look at their baby.

You will probably be given a grainy picture of the ultrasound as a keepsake. It may also be possible to find out the sex of your baby if you want to. However the main purpose of the ultrasound is to gain vital information about your baby's health and development.

If your pregnancy is consider low-risk, however, you might not be offered an ultrasound at all. In truth, the American College of Obstetricians and Gynecologists recommends ultrasound is only used when there's a specific medical reason. According to the March of Dimes, around 70% of pregnant women in the United States are given ultrasounds.

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