Multiple pregnancies require intensive monitoring of the fetal conditi
on, in particular during the last months of pregnancy. Recording fetal
behaviour offers a possibility of investigating the neuromotor develo
pment, in twin pregnancies even behavioural patterns of fetuses of the
same gestational age and ''environment'' may be compared. In 25 prima
rily uncomplicated twin pregnancies we simultaneously recorded antepar
tum FHR and FM patterns in twins younger than 36 completed gestational
weeks over a period of at least one hour via a new device for simulta
neous registration of FM and FHR in twin pregnancies. According to our
longitudinal observations we have defined a special terminology for c
omparing the behaviour of twins considering gestational age, differenc
es of FHR or FM patterns and the continuity of these patterns througho
ut gestation. To our opinion this will open a new field not only for c
linical diagnostics in complicated twin pregnancies but also for devel
opmental research of the possible impact on the further neurological d
evelopment of multiple fetuses. Human behaviour in its early stage may
be compared considering even ''interfetal communication''.