Objective: To determine the applicability of the Acute Physiology and
Chronic Health Evaluation (APACHE) II scoring system in predicting out
come in a subgroup of critically ill obstetrical patients. Design: Ret
rospective data collection. Setting: A multidisciplinary intensive car
e unit (ICU) in a university hospital. Patients: All patients (n = 1,6
70) admitted for >24 hrs to the ICU during an 8-yr period, of whom 58
were obstetrical patients and 120 were nonobstetrical young women. Mea
surements and Main Results: The mean APACHE II score in the obstetrica
l group was 11, with a mortality risk of 16.6%. In this group, the mor
tality ratio, which is the ratio between actual and predicted mortalit
y rate, was low (0.416) and significantly (p = .021) different from th
e expected mortality ratio of 1. The mean APACHE II score in the group
of nonobstetrical young women was 10, with a mortality risk of 10.17%
. In all nonobstetrical ICU patients including all the admitted patien
ts excluding the obstetrical patients, the mean APACHE II. score was 1
5, with a mortality risk of 24.18%. The mortality ratio in the nonobst
etrical young women group and in the nonobstetrical ICU patient group
was 0.986 and 1.006, respectively, which was nonsignificantly differen
t from the expected mortality ratio. Conclusions: Obstetrical patients
requiring intensive care in our ICU had a better outcome than predict
ed, as expressed by a low mortality ratio. Various explanations that m
ay be applicable to any subgroup of critically ill patients with a dif
ferent mortality ratio are presented. The subgroup itself may be uniqu
ely different, similar to our obstetrical patients with their physiolo
gic changes of pregnancy. Another explanation may relate to an improve
ment in care of the subgroup and therefore a better outcome.