Is endomyometrial injury during termination of pregnancy or curettage following miscarriage the precursor to placenta accreta?

AIMS: To determine the frequency with which myometrium is removed during vacuum terminations of pregnancy or dilatation and curettage after miscarriage, and to relate these findings to subsequent placenta accreta or its proxies.
METHODS: Archival tissues from vacuum termination of pregnancy or dilatation and blunt curettage after miscarriage were examined for the presence of myometrium. The subsequent obstetric histories were scrutinised for manual removal of placenta, postpartum haemorrhage, or retained placenta. A retrospective study comparing the frequency of miscarriage and termination in women who had or did not have a manual removal was also performed.
RESULTS: Myometrium was seen in the products of conception in 44% and 35% of termination and miscarriage tissues, respectively. One of nine women with myometrium at miscarriage had a postpartum haemorrhage in a subsequent pregnancy whereas, of the 21 women without myometrium at miscarriage, three required manual removal and seven had a postpartum haemorrhage afterwards. A past history of termination and/or miscarriage was more frequent in multigravid women who had a manual removal than those who did not.
CONCLUSIONS: Endomyometrial injury is frequent at termination or dilatation and curettage after miscarriage, but the relation to subsequent placenta accreta remains unclear. Women requiring a manual removal of the placenta were likely to have had a past history of termination and/or miscarriage.