Placenta previa. Placenta previa is more likely with an anterior placenta. (This would be seen at your anatomy ultrasound ...

Multiple logistic regression was used to adjust the estimates for maternal age, ethnicity, deprivation, placenta previa at first birth, inter-birth interval and pregnancy complications.

The risks of placenta previa in the second pregnancy also increased by previous placenta previa, advanced maternal age and with birth intervals of less than one year or more than four years.