TITLE: MENSTRUAL CYCLE IRREGULARITY AND THE INCIDENCE OF NAUSEA AND VOMITING AFTER LAPAROSCOPY

AUTHORS: Dominic C. Harmon, FCARCSI, Paul O'Connor, FFARCSI, Mark Lennon, FCARCSI, Vida Hamilton, FCARCSI, Omimah Gleasa, MB, James Gardiner, FCARCSI
AFFILIATION: Rotunda Hospital, Galway, Ireland.

INTRODUCTION: Risk factors for the development of post- operative nausea and vomiting include both patient and surgical factors. There is a higher incidence in females¹, which varies with menstrual cycle phase². This variation is believed to be mediated by female sex hormones. It has not been established, whether menstrual cycle irregularity can predispose to postoperative nausea and vomiting.
METHODS: A prospective, blinded, observational study was designed. Patients (n=159) aged 21-40 years, ASA I-II scheduled for laparoscopy and dye investigation were included. This was part of a series of infertility investigations. On the day before surgery, menstrual history and the first day of the last menstrual period were asked from the female patients. Patients were asked whether they considered their cycles to be regular or irregular. Patients were divided into two groups; regular and irregular menstrual cycle groups. A regular cycle was defined as that lasting at least 21 days or at most 35 days, with no more than a 4- day variation between cycles³. Criteria for exclusion included amenorrhea and a previous history of post-operative nausea and vomiting. Anaesthetic technique and post-op analgesia was similar for both groups. Prochlorperazine 12.5 mg i.m. was prescribed for intolerable nausea or vomiting. Patients were assessed for nausea and vomiting in the recovery room at 2 and 24 hours later by a blinded Anaesthetist. Data were analyzed using the Chi-square test, with 95% confidence limits.
RESULTS: The two groups were comparable in their age, weight, and surgical procedure duration. The overall incidence of nausea and vomiting was 25.5%, with 23% of patients having irregular cycles. The irregular menstrual cycle group (n=37) had a significantly higher incidence of nausea and vomiting over 24 hours, as compared to the regular menstrual cycle group (n=122) (40.5% versus 20.5%, P=0.01, 95% CI 0.03-0.37). When analyzed separately, both nausea (P=0.006, 95% CI 0.17-0.21) and vomiting/retching (P=0.0003, 95% CI 0.15-0.22) were significantly increased in the 24^th post anaesthesia, in the irregular menstrual cycle group. Anti-emetic requirement as greater in the irregular group (P=0.008, 95% CI 0.14-0.16).
DISCUSSION: A history of an irregular menstrual cycle is a common finding in women of reproductive age⁴ presenting for surgery. An irregular menstrual cycle increases the risk of post- operative nausea and vomiting. A hormonal mechanism is probable, but as yet not defined. A history of an irregular menstrual cycle should be controlled in studies of post-operative nausea and vomiting.
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