Strengths and limitations
This is the first large-scale, multi-province, retrospective cohort
study that investigated prevalence of postpartum contraception,
unintended pregnancy and induced abortion nationwide in China. The study
manifests several limitations. Our study relied on women’s retrospective
reporting of their postpartum contraception, pregnancy, and abortion;
and hence may be subject to recall bias. We recorded the timing with
respect to initiation of postpartum contraception, resumption of sexual
intercourse, pregnancy, and abortion by rounding the number of months;
and this may not have provided adequate accuracy in measuring cumulative
rates.