Participants
We identified 201 pregnancies exposed to the BDZ group and 386
pregnancies not exposed to BDZ in the period of interest. In the exposed
group, six pregnancies were excluded because of multiple births and one
for a stillbirth. Of the remaining 194 singleton live birth pregnancies
in the exposed group, a total of 25 pregnancies were excluded for the
following reasons: pregnancies with an actual diagnosis of epilepsy,
pregnancies with congenital malformations in one of the parents, or
exposure to teratogenic drugs. For the same reasons and due to missing
data about the primary and secondary outcomes, 42 pregnancies were
excluded and nine multiple births pregnancies from the reference group.
As a result, 169 pregnancies in the exposed group and 335 pregnancies in
the reference group were eligible. In presence of more than one
pregnancy from the same mother we randomly selected a pregnancy in our
dataset. See figure 1 for the details on patient selection. The final
dataset consisted of 147 pregnancies in the exposed group and 294
pregnancies in the reference group.
Both groups differed in maternal and clinical characteristics, see table
1. In the BDZs exposed women used more alcohol during pregnancy (4.1%
vs 0.7%, p = 0.019), had lower number of mental disorders (p=0.010), a
higher number of concomitant psychotropics (p<0.001), and
needed longer psychiatric care after delivery (p<0.001), see
table 1. Duration of pregnancy was shorter in the BDZs exposed group,
269 days for the exposed group and 274 days for the non-exposed group,
p<0.001.