Richard Hyer

May 13, 2009

May 13, 2009 (Chicago, Illinois) — Successful pregnancy can be predicted with up to 94% accuracy between days 33 and 36 using transvaginal ultrasound to detect 3 markers, according to new findings presented here at the American College of Obstetricians and Gynecologists (ACOG) 57th Annual Clinical Meeting.

The findings were presented by lead author Soyoung Bae, MD, from the Department of Obstetrics/Gynecology, University of Toledo Medical Center in Ohio. Dr. Bae's study was awarded ACOG's third-place prize.

"On postconception dates 33 to 36, gestational sac diameter of 12 mm and above, yolk sac diameter of 2 to 6 mm, and presence of fetal cardiac activity were all significantly related to successful pregnancy outcome in healthy women," Dr. Bae said. "These markers were associated with favorable pregnancy outcome even in the poor prognostic subgroups of women of advanced maternal age and those with recurrent pregnancy loss."

The study was designed as a case–control study of 1092 pregnancies, the majority of which were conceived with infertility treatments, so the precise date of conception could be known. The objective was to identify ultrasound markers to predict successful pregnancy in early pregnant patients.

Investigators performed transvaginal ultrasound at postconception days 33 and 36 to measure fetal cardiac activity, gestational sac diameter, and yolk sac diameter.

"On postconception day 33 to 36, investigators found that if they could identify fetal cardiac activity, the success rate was approximately 90%. Without cardiac activity, the miscarriage rate was approximately 88%. If the gestational sac was more than 12 mm [in diameter], the pregnancy's success rate was about 92%; if it was less than 8 mm [in diameter], the miscarriage rate was about 96%. Gestational sac size diameter between 8 and 12 mm was a gray zone; the success rate was about 66%," said Dr. Bae.

The majority of yolk sac sizes were between 2 and 6 mm in diameter, and this forecast successful pregnancy in about 90% of women.

Thus, the presence of fetal cardiac activity, a gestational sac diameter of more than 12 mm, and yolk sac size between 2 and 6 mm in diameter were all associated with a successful pregnancy. If all 3 markers were visible and within those stated ranges on days 33 to 36 postconception, successful pregnancy could be predicted with 94% accuracy, Dr. Bae observed.

For women older than 40 years, the rate of successful prediction was 82%. For women with a history of recurrent pregnancy loss, if all 3 markers were present, the rate of accurate prediction was 94%.

Commenting on the results to Medscape Ob/Gyn & Women's Health was Kurt L. Barnhart, MD, MSCE, member of ACOG's Committee on Scientific Program. Dr. Barnhart is director of women's health research at the University of Pennsylvania in Bryn Mawr, and served as director, with Janice L. Bacon, MD, of the Papers on Clinical and Basic Investigation.

"Ultrasound markers of an early pregnancy are often used to diagnose miscarriage," Dr. Barnhart said. "If something is not growing according to the milestones expected, then we think perhaps the pregnancy is going to result in a miscarriage. This [study] is a very good quantification of what some of those signs are, and suggests that perhaps early changes can be used to classify someone as high or low risk, rather than just waiting for the miscarriage to occur.

"This is using ultrasound to predict the miscarriage, rather than solely to diagnose it," Dr. Barnhart concluded.

The study was funded by the University of Toledo Medical Center. Dr. Bae has disclosed no relevant financial relationships.

American College of Obstetricians and Gynecologists (ACOG) 57th Annual Clinical Meeting: Papers on Current Clinical and Basic Investigation. Presented May 4, 2009.


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