Lhj. Eberhart et al., A systematic review of studies investigating the impact of the menstrual cycle on the incidence of postoperative nausea and vomiting, ANAESTHESIS, 49(6), 2000, pp. 532-535
Objective. Several studies suggest that the menstrual cycle has an impact o
n postoperative nausea and vomiting (PONV). However, many studies report in
consistent results. Thus, in this systematic review the results of all avai
lable studies are compared and statistically synthesised.
Materials and methods. A systematic search of the literature was performed
(Medline, the Cochrane-Library, reference lists of matching articles). The
main end point in each study was defined as occurrence of PONV during an ob
servation interval of at least 12 h postoperatively. These data were extrac
ted from each article and the pooled incidences of PONV for each day of the
menstrual cycle were calculated. These incidences were analysed using the
chi(2)-test. Furthermore the pooled incidences of PONV during the following
phases of the menstrual cycle were calculated: days 1-7,8-12, 13-15,16-24,
and 25-end of cycle.
Results. A total of 12 studies with 2625 patients containing informations o
n the incidence of PONV on different days or phases of the menstrual cycle
were analysed. The total incidence of PONV was 37.3%. The incidence of PONV
was lowest (26.9%) on day 20 and reached its maximum on day 5 (45.0%) with
no statistically significant differences concerning the incidences of PONV
between the different days (p=0,75). Furthermore there were no clinically
relevant differences in the incidences of PONV during the phases of the men
strual cycle: day 1-7: 40,4%; day 8-12: 32,9%; day 13-15: 38,1%; day 16-24:
34,5%; day 25-end of cycle: 41,5%. Prophylactic administration of an antie
metic in some of the studies had no impact on these results.
Conclusion. Studies investigating the influence of the menstrual cycle on t
he incidence of PONV show inconsistent results. Summarising the data of the
se studies suggests that the phase of the menstrual cycle has no impact on
the occurrence of PONV.