Objective: The etiology of recurrent spontaneous abortions (RSA) in chromosomally normal parents is still unexplained. It is unclear whether or not some factors, such as spontaneous abortions (SA), which occur among extended family members can create a predisposition to RSA. Therefore, this study comprises two parts: (a) an epidemiological part, to evaluate the relationship between RSA in 567 couples and the frequency of SA among their first (I), second (II) and third (III) generation relatives, and (b) a genetic part, investigating whether parental and fetal chromosomal status may predispose to the occurrence of RSA.
Study design: Couples (567) having one or more SA were analyzed in this retrospective case-control study. The family reproductive history data was collected from their medical charts.
Results: The total number of SA found in 567 couples was 1174, and the largest number occurred at 8-10 weeks of gestation. The majority of spouses had normal karyotypes (88.5% and 91%). Of the remainder, 65% of females and 76% of males expressed constitutional chromosomal variation, mostly pericentric inversion of chromosome 9. Cytogenetic analysis of aborted material showed some type of change in 40% of cases. The family reproductive history data indicated that SA among the couples' I, II and III generation relatives happened with a frequency two to three times higher than that of the general population (55.5, 47.6 and 32.6% for female relatives, and 45.8, 44.1 and 15.1% for male relatives).
Conclusion: Positive reproductive family history for SA might be the causal factor for RSA and can also predetermine women that are of greater susceptibility to preterm pregnancy.
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