According to a report, slow embryo heart rate is a clue that mothers who have undergone in vitro fertilization are at increased risk for miscarriage.

Nearly 10 and 25 percent of women who undergo in vitro fertilization suffer miscarriages, and slow embryonic heart rates have been known to be a sign of trouble. However, The boundary between slow and normal embryonic heart rates has not been well established in the infertile population, study co-author Dr. Zev Rosenwaks, of Weill Medical College of Cornell University, New York, and colleagues write.

The study involved 95 women with miscarriage in the first trimester and 555 without miscarriage. Except from this difference, the two groups were similar. Transvaginal ultrasound performed was between 1 and 2 months into the pregnancy.

The study reported that slower embryonic heart rates were seen in the miscarriage group. Consistent with previous research, women with miscarriage were significantly older than those without miscarriage.

This study was carried out to see if embryonic heart rate could be an added marker for potential viability…or, conversely, for potential miscarriage, Rosenwaks told Reuters Health.

The author reported that a fetal heart rate higher than 130 beats per minute at approximately 7 weeks was associated with a 92 percent chance of carrying the pregnancy to term. A heart rate of 160 was linked to an even greater chance of carrying the pregnancy to term-98 percent.