Publication:

Ultrasonographic placental localisation and extent of invasion in scarred versus non-scarred uterus and its correlation with obstetrical outcomes: a prospective study

Background The site of implantation and resultant location of the placenta within the uterus are likely important determinants of placental blood flow and therefore pregnancy success. Abnormal placental implantation or ‘placental invasion’ is a rare, but potentially life‐threatening, complication in the third stage of labour. Currently massive obstetric haemorrhage remains one of the leading causes of maternal mortality.

Methods 140 antenatal women at ≥34 weeks of gestation were selected, out of which 70 had the history of previous caesarean section and 70 had the history of previous vaginal delivery. Detailed USG was done with special emphasis on edge to os distance (EOD), extent and depth of invasion of placenta. All cases were followed till delivery and their intraoperative assessment done and correlated with sonographic findings and obstetrical outcomes.

Results With increasing number of previous caesarean section, depth and extent of invasion of placenta increases and edge to os distance (EOD) decreases. 8.5% cases with previous 1 caesarean section, 22.22% cases with previous 2 caesarean section and 50% cases with previous >2 caesarean section had some adherence of placenta.

Conclusions Uterine scar increases chances of low implantation of placenta as well as its adherence as compared with unscarred uterus. This risk increases with number of caesarean sections. These high-risk cases of scarred uterus especially those with multiple scars should be subjected to detailed sonographic scan by expert radiologist.