Obstetrical Ultrasound - A Sinister Cause for Concern?
Monday, October 08, 2007
Kenneth F. Trofatter, Jr., MD, PhD
A few minutes later, our nurse came out of the room to tell me that the patient was VERY upset. Now, in our business, it is not at all unusual to discuss a pregnancy complication with a patient who maintains a stoic face throughout the discussion and then falls apart when left alone with the nurse, but I was a little surprised in this case because I thought the conversation had gone well, the condition was not serious, the baby was fine, and the patient herself had smiled and expressed gratitude for the clarity of the discussion. “It’s not what you think,” the nurse told me, “She wants to know why we didn’t do another ultrasound today because she always has one done at each of her OB visits in her doctor’s office...”
I had just reviewed her records, I knew she had had multiple ultrasounds performed in her provider's office, the most recent being just a few days before her visit with me, and according to her report and the office notes, “the baby was growing well and had no problems.” Now, you have to understand, as a specialist in Maternal-Fetal Medicine, much of my kids’ college educations are going to be funded by the many ultrasound-based procedures we perform on a daily basis. However, as part of my devotion to the admonition primum non nocere (above all, do no harm), I have always considered myself rather conservative in the number of ultrasound studies I perform and rarely will do one without some clinical indication. So, there was something that made me very uncomfortable about her request. And, to be honest with you, part of that discomfort was fueled by a recent query from one of our readers who asked me if it was true that ultrasound increased the risk that her baby would be lefthanded (we will return to that question in the next post).
Primum non nocere reminds us that we must consider the possible harm that any intervention might cause and that human acts with good intentions may have unwanted consequences. Although I do not have the statistics to back this up, I would wager that more than 80% of pregnant women in the U.S. today will have one or more ultrasounds done during their pregnancies. And this is not the first patient who has told me that an ultrasound was part of every prenatal visit. Ultrasound is so widely considered completely ‘safe’ that if you have enough money, like Tom Cruise, you can buy your own machine and use it every day; and “Fetal Foto” shops, employing 3-D and 4-D ultrasound imaging are springing up in strip malls all around the country for anyone who wants to pay cash to (possibly – no refund if they don’t get it) get a pretty picture of their baby before birth. But let me remind you that we also considered DES to be ‘safe’ and, indeed, many practitioners used it for years after it was recognized that it might not be.
In 2003 (Ultrasound Obstet Gynecol 2003;21:100), the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) reaffirmed an earlier “Safety Statement” in 2000 that “based on evidence currently available, routine clinical scanning of every woman during pregnancy using real-time B-mode imaging is not contraindicated.” This statement is predicated on the fact that ultrasound performed in the B-mode for routine 2-D, gray-scale imaging is conducted at very low levels of energy intensity and that in 40+ years of its use, no reproducible serious side-effects have ever been demonstrated.
However, ultrasound is ‘energy’ and its use is accompanied by the generation of heat (and other effects) and, indeed, it is widely used at higher intensities as a therapeutic modality in physical therapy (for which my left shoulder is very grateful, but my shoulder is not a baby). Furthermore, those of us who were trained during the era of ultrasound evolution tend to forget that not all ultrasound imaging for obstetrical purposes is created equal in terms of energy intensity. Our senses have been dulled by the mantra of ‘safety’ of B-mode scanning and have, without the data to back us up, extended the cavalier attitude to the routine and frequent use of both “spectral and color Doppler” for many diagnostic purposes in obstetrics that as the ISUOG statement reminds us “may produce high intensities…(and) because of high acoustic absorption by bone, the potential for heating adjacent tissues…”
It is true, we are given the admonition that “exposure time and acoustic output should be kept to the lowest levels consistent with obtaining diagnostic information and limited to medically indicated procedures, rather than for purely entertainment purposes.” But, by the same token, we have been given very little guidance over the years in terms of what that actually means. How many ultrasounds, how much exposure, how should exposure differ by gestational age? The human experiments have never been done, prospectively, and it is not realistic to think they will be at this point! But some observations related to ultrasound exposure fetal outcomes have been reported in obstetrical patients over the years and in our next post we will briefly discuss a few of those…
8 Comments:
At Wed Oct 10, 06:08:00 AM 2007,
Jen said…
Hello, I am a 34 years old pregnant with my first child. At my 12 wks US the doctor said the baby has Cystic Hygroma w/ a 5 mm measurement. At 13 weeks I went in for a CVS and the doctor said there might be a NT instead. After that said the doctor could not perform the CVS because the fetus was to tilted back and he couldn't get through the cervix the other way. He said in his 38 years of experience he has never seen this problem. I was then told to go to Yale in CT for a second oppinion and did, where they were able to perform the CVS at 14 and a half weeks pregnant. 7 days later my test results came back with no chromosomes problems. My husband and I also did genectic testing and also came back with normal chromosomes. My question now, is what is my chances of having a normal baby? I will be going in at 17 wks for another US to take a closer look. Is this normal to have a fetus w/ CH with no chromosomes problems.?
At Wed Oct 10, 11:22:00 PM 2007,
Bijili said…
Hi Dr.Kenneth,
I am 36 yrs old and I have been married for 13 years and have had 13 miscarriages so far.I have done many tests including Chromosomal Analysis. My results were 46 XX 21ps+...21ps+ is an increase in size of the satellites on one homologue of chromosome 21. My Husbands result was 46 XY qh+..The Karyotype shows an elongation of the long arm of the Y chromosome.
We also did another test called Th-1 type cytokine estimation. Nmae of the test TNF-a..the normal range was upto <200 pg/ml but my count showed 703.299.
We are so desperate to have a child.Could you please give me some advise as to why this is happening . I will be really grateful to you if you could reply me through my email. Thanks a lot in advance.
Liz
At Wed Oct 10, 11:52:00 PM 2007,
Anonymous said…
I have been reading your posts for the last couple of months with great interest! I found you while searching the net for information on miscarriage. My daughter (age 23, newly married)lost her first baby at 7 weeks in July. Being an RN in pediatrics, I did not know much on the subject and wanted to learn as much as I could about miscarriages and possible causes and preventions in future pregnancies. You have been very informative and I have learned so much! Your warmth, care and advice for the women who write to you is wonderful and a great service! This was a very traumatic loss for my daughter, her husband and us, as it was our first grandchild. I know it was her 1st m/c and the 1st is usually brushed off as an isolated event but I still wanted to be armed with as much knowledge as I could going into her next pregnancy. I was reassured by your posts on early pregnancy loss and 1st pregnancies having a higher possibility for rejection from her body to the new foreign object and that future pregnancies might not have that happen. Her OB was skeptical of that as a cause. But I think it makes sense. (And it gave us hope that it was as simple as that and not other more difficult to solve problems.) She is now joyfully 7 weeks pregnant today! It has been an anxious time for her as she is so afraid the same thing will happen again. Her hcg levels have been doubling every 3 days consistently, so that is reassuring to her, although at this point she is no longer having that done. Her OB put her on progesterone tablets and wants her to d/c them at week 9. This brings me to my questions I have for you. In your recommendations you do not put progesterone as a usual preventative thing in your advice, what do you think about it, and how long should she be on it? I agree with you wholeheartedly in your post about being careful about any potentially harmful tests or medications that we do. I felt that way about her being on progesterone because I thought about the DES tragic history. But the OB reassured us that it was not harmful. But when I had my 2 children 26 and 23 years ago, I refused to have routine u/s for fear that those "harmless" sound waves would someday show harm done to my children. Now they are done with alarming frequency to my liking. I have discouraged my daughter from having one this early in her pregnancy, just to see that the heart is beating, because of potential problems down the line. She also has friends that have u/s done at every prenatal visit, which I find disturbing too! Her OB usually only does one at 18-22 weeks as routine screening. What do you think about that? They have the new lifelike color image machines and I have wondered about the safety of those. What kind of u/s would you recommend be done at that 18-22 week screen? And do you think that the benefits to that one u/s outweigh the potential risks? Everyone seems so excited about the new prenatal detailed color pictures that are taken and finding out the gender of the baby, but it worries me for the reasons you stated. My husband is a pediatrician and our daughter and her husband regard our opinions on these things highly. I look forward to reading more on your posts. Thank you so much for imparting your knowledge and experience to everyone out there seeking it. LB
At Thu Oct 11, 06:34:00 PM 2007,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Jen Oct 10: I am sitting here wondering whether the baby really had a cystic hygroma to begin with! Did they see it when you went to Yale, was the nuchal translucency widened, and did they see any other abnormalities or find Doppler flow abnormalities of the fetal ductus venosus (I am sure they did them if you went to Yale!). But presuming he/she did have a cystic hygroma, only about 50-60% of these are associated with chromosomal abnormalities and you have already passed over that problem! A certain percentage are associated with congenital heart defects and syndromic problems and, hopefully, that will be sorted out with the next ultrasound. If the cystic hygroma resolves, the baby is chromosomally normal, and no other fetal abnormalities are seen, there is a reasonable chance the baby will be allright. I cetainly hope so. Please let me know how things turn out! Thank you for reading and best of luck! Dr T
At Mon Oct 15, 06:31:00 AM 2007,
Anonymous said…
hello doctor,i m 23yrs old,i first conceived in june 2007 but due to some complication i had my D&C done.i heard that after D&C 3 months should be safe but in 2nd month i conceived again so is there will be any complications with me and any extra precautions that i should take care for?
At Mon Oct 15, 01:52:00 PM 2007,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Anonymous Oct 10: Whew girl, that was a mouthful. But, I do appreciate the positive feedback. With regard to the progesterone, I have absolutely NO qualms about that. It is natural progesterone and should be exactly like what the ovary (early on) and then the placenta make during pregnancy. In your daughter's case, who really knows if she needed it but, unlike DES, which was used for the same purpose, it is HIGHLY unlikely that progesterone would cause any harm. And, even if I don't mention it, we frequently use it in addition to other forms of empiric therapy and in women who have any hint at all of ovulatory dysfunction or 'luteal phase defects.' If an ultrasound is done at no other time in pregnancy, I suggest it be done at 18-22 weeks. That is when we do our 'targeted' scans to assess fetal anomalies. Most major abnormalities can be detected by this time, and many will be missed later if not picked up then, simply because of the fetal growth and imaging quality later in the pregnancy. The color spectral and Doppler ultrasound imaging modalities do use higher intensities of ultrasound, but again, in reasonable xposures (and probably most cases of UNREASONABLE exposures), the likelihood of fetal damage appears to be very Low. Good luck Grandma and my best to your daughter too!
At Wed Oct 17, 07:51:00 AM 2007,
Anonymous said…
Hi Dr. Trofatter. In addition to anonymous from Oct. 15. When should one consider getting pregnant again after a D & E procedure ( 17-th week ). This was a twin pregnancy with the first fetus being selectively terminated at 12 weeks. I see a lot of answers with "magic" 3 months after anything shorter than full-time delivery. I was curious if this is true since it would appear that body would take longer to recover after 17-week pregnancy ( + twins ) vs D & C procedure performed during first trimester on a singleton pregnancy.
Thank you!
At Fri Oct 19, 08:13:00 PM 2007,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Anonymous Oct 17: I think there are some advantages, both physically and psychologically, to waiting a little longer with midtrimester losses and D&Es. That must have been a rough pregnancy. It wouldn't be the end of the world if you conceived in 3 months, but 6 would be my suggestion under the circumstances you describe. Sorry for your losses and hope things turn out better the next time. Dr T
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