“The investigators conclude from these data that previous elective pregnancy terminations should be considered a risk factor for premature birth in subsequent pregnancies.”
A chart of their research is included below:
As you can see from the chart, the Primigravidae group of women that have never had an abortion had a spontaneous abortion (miscarriage) rate that was lower than those who had a prior induced abortion.
The study also estimated how many first-trimester miscarriages were due to past induced abortions, saying:
“we estimate thatabout 15% of first-trimester miscarriages in Shanghai can beattributed to prior history of induced abortion”