In addition, the
association between pre-eclampsia and parity could be
estimated in both data sets. In MoBa, the adjusted odds
ratio for pre-eclampsia comparing parity 1 to parity 0
was 0.46 (95% CI: 0.42-0.50), while it was 0.47 (95%
CI: 0.45-0.49) in the total population. These figures
are reassuring, and suggest that projects using preeclampsia
based on MoBa data will most likely not
suffer from recruitment bias to any large extent.