Dec. 2, 2003 (CHICAGO) -- Miscarriage during the first 12 weeks of pregnancy is a common, but not well-understood occurrence. But now there may be an explanation.
Imaging technology that allows researchers look at the fetal heart in real time indicates that many early miscarriages may be caused by fetal heart problems that mimic congestive heart failure -- a condition usually diagnosed in adults. As many as 20% of all pregnancies end in miscarriage.
Moreover, radiologist Jason Birnholz, MD, president of Diagnostic Ultrasound Consultants, in Oak Brook, Ill., says the condition can be easily diagnosed by use of Doppler ultra sound -- an imaging technique that uses sound waves to track the pumping action of the heart.
Congestive heart failure is marked by inefficient pumping of blood through the heart, which starves organs of needed oxygen. Eventually, fluid builds up in the lungs making it hard to breathe. Birnholz says the Doppler ultrasound allows him to identify this abnormality in 10-week-old fetuses.
Based on Doppler ultrasound exams of 1,800 pregnant women, Birnholz says that 98% of fetuses who have fetal congestive heart failure at six to 10 weeks gestation will not survive until the fourth month of pregnancy. The flip side, he says, is that "99% of fetuses who have no evidence of congestive heart failure at first examination will make it to the second trimester."
"Some of these women had symptoms such as bleeding, while others had a history of miscarriage. In other cases it was done just to ease maternal anxiety," he says.
At the initial ultrasound "475 women had no evidence of fetal heartbeat but did have evidence of excess fluid accumulation that was, again, suggestive of fetal congestive heart failure." This indicates that the fetal demise might have been caused by congestive heart failure.
In addition, 125 fetuses died subsequent to the first exam, and all had evidence of heart dysfunction by Doppler, Birnholz says.
Following his presentation, Birnholz was peppered with questions from a skeptical audience of radiologists, many of whom suggested that predicting early miscarriage with Doppler technology was not yet ready for prime time.
"We have known for some time that a slow heart beat was a bad sign, but we didn't know why," Julia Fielding, MD, associate professor of radiology, University of North Carolina, Chapel Hill tells WebMD. "This is new since Doppler hasn't been used this way." Fielding was not involved in the study.
But, "the problem is that this is one study, from one investigator, at one center. It needs to be validated by probably two more studies," she says. The bottom line, is that "this is a great use of technology," but we cannot use this finding in practice at this point, she said.
Asked by WebMD if he would recommend early Doppler ultrasound fetal assessment for all pregnant women, Birnholz replied, "I'm not making any statement about recommendations. I'm just presenting these findings."
But he did say that based on his findings, increasing the oxygen supply to the mother, which he says is simple might improve the heart function in the fetus. "But this is only speculation and would need to be tested in a large clinical study," he tells WebMD.