Infection, abnormal cervical competence: trimester of recurrent fetal loss sets evaluation.(Obstetrics)

NEW YORK -- A diagnostic work-up is indicated when a woman has had at least three first-trimester spontaneous abortions or just one pregnancy loss in the second or third trimester. Dr. Anthony Vintzileos said at an obstetrics symposium sponsored by Columbia University and New York Presbyterian Hospital.

If the mother is older than 35, a work-up should be done after two first-trimester losses or one subsequent loss, added Dr. Vintzileos, professor and acting chair of the department of obstetrics, gynecology, and reproductive sciences at Robert Wood Johnson Medical School. New Brunswick, N.J.

Data suggest that the overall chance of a second pregnancy loss after just one first-trimester loss is about 13.5%, not much higher than the 13% rate among those with no previous pregnancy losses. Among those with two first-trimester losses--occurring in about 5% of all couples--the recurrence rate increases to about 25%, and up to 33% with at least three losses.

The recurrence rate is elevated 5- to 20-fold after just one pregnancy loss during the second or third trimester, however.

The rates of pregnancy loss decrease with increasing gestational age, from 55% during preimplantation (0-6 days gestation) to 25% at 7-13 days to 8.2% by 14-20 days and to below 1% by 18-21 weeks. And as those rates drop, the most common causes for the losses change. That's why the textbook definition of "recurrent early pregnancy loss" as at least three spontaneous abortions occurring before 20-22 weeks doesn't really make sense, he said.

"Losses prior to 20-22 weeks have a diverse etiology. [This definition] doesn't help in managing the patient," he said.

Sonohysterography/hysteroscopy and a review of placental/fetal pathology are indicated for work-up in all cases of recurrent pregnancy loss. For repeated first-trimester losses, parental karyotyping and testing of ovarian function should also be part of the evaluation.