When a pregnant women experiences bleeding or pain early in the pregnancy, she may undergo an ultrasound to determine if a miscarriage has occurred. Doctors measure the embryo and other markers to determine whether or not the pregnancy is progressing normally. If there is a question about embryo size, another measurement is taken about a week later. Researchers believe faulty measurements and slow growth could be mistaken for miscarriage, causing some women to terminate a healthy pregnancy due to a misdiagnosis of miscarriage.

Embryonic growth is subtle during the first few weeks’ gestation. If there is a slight measurement mistake during either ultrasound, the pregnancy could be diagnosed as a miscarriage. Researchers asked different clinicians to measure embryos during the earliest weeks of gestation. Measurements varied by up to 20%. If the first ultrasound measures the embryo larger than actual size and the second ultrasound measures the embryo correctly a little more than a week later, it may look as though the embryo is not growing. This is the base evidence doctors are looking for when diagnosing miscarriage.

While miscarriage diagnosis is important in all cases, women undergoing IVF treatment and other costly fertility treatments spend thousands of dollars for treatments so diagnosis of miscarriage needs to be accurate and dependable.

Researchers worry that women are being given miscarriage diagnosis when the pregnancy is viable and healthy. Tom Bourne, professor at Imperial College London states, “By identifying this problem we hope that guidelines will be reviewed so that inadvertent termination of wanted pregnancies cannot happen. We also hope backing will be given to even larger studies to test new guidelines prospectively. Currently there is a risk that some women seeking reassurance with pain or bleeding in early pregnancy may be told they have had a miscarriage, and choose to undergo surgical or medical treatment when the pregnancy is in fact healthy.”

Researchers involved in the study did not offer viable alternatives to current miscarriage diagnosis guidelines.

Source: Jeve Y, Rana R, Bhide A, Thangaratinam S. Ultrasound Obstetrics and Gynecology. 13 October, 2011.