Objective: To evaluate the prognostic value of transvaginal ultrasound (TVUS) detection of fetal heart motion (FHM) in view of maternal age and chromosomal analysis of spontaneously aborted fetal tissue.
Design: A 3-year retrospective, descriptive study.
Setting: Two medical center-based infertility-care facilities.
Patient(s): 336 pregnancies were initiated by intrauterine insemination or embryo transfer for women of reproductive age who were seeking infertility treatment.
Intervention(s): None.
Main outcome measure(s): beta hCG levels measured > 40 mIU/mL at 4-5 weeks' gestation and were followed by an initial TVUS at 5-8 weeks. Of these pregnancies, 52 ended in a first trimester loss. Twenty were defined by failure to detect FHM by 7 weeks' gestation (Group I), and 32 were marked by the loss of prior FHM at a mean of 2.6 weeks later (Group II). Fetal tissue was removed by dilatation and suction curettage. Cytogenetic studies were performed from short-term cultures of dissected chorionic villi and/or sac.
Result(s): Chromosomal aberrations were found in 75.0% of abortuses in Group I and 65.6% in Group II. Different types of chromosomal abnormalities were present in each these groups. The maternal age-related trisomies which can progress to term (i.e., 13, 18, 21) were associated with early TVUS detection of FHM. The frequency of chromosomal abnormalities varied significantly with maternal age, with normal fetal karyotypes in 7 of 11 (63.6%) women < 35 years, but only in 9 of 41 (22.0%) women > or = 35 years despite the detection of FHM in 24 of 41 (58.5%) of these older women. Detection of FHM was associated with pregnancies continuing beyond the first trimester in 284 of 316 (90.0%) overall, but differed significantly with age (166 of 174 [95.4%] women < 35 years vs. 118 of 142 [83.1%] women > or = 35 years).
Conclusion(s): Although the occurrence of chromosomal abnormalities in spontaneous demises did not differ according to TVUS detection of FHM, the types of aberrations were distributed differently. Since maternal age remains a significant factor in early fetal loss, TVUS detection of FHM should not be as reassuring for women > or = 35 years as for younger women.