Objective: To determine whether women with premenstrual syndrome (PMS) differ from healthy women in the extent of hyperventilation during the luteal phase of the cycle.
Design: Case report.
Setting: Medical university.
Patient(s): Three reproductive-age women with severe symptoms of PMS in whom dramatic decline in end-tidal PCO2 (PETCO2) occurred during the luteal phase of the cycle.
Intervention(s): Measurements of PETCO2, administration of GnRH agonist triptorelin.
Main outcome measure(s): PETCO2 was determined daily by sidestream capnometry.
Result(s): The decline in PETCO2 in women with PMS was 12-18 mm Hg, on the average. This was significantly more pronounced than the decline of PETCO2 that was observed in healthy women. With the decline of PETCO2 the symptoms of PMS appeared. Symptoms disappeared at the end of the luteal phase when PETCO2 was increasing again. During treatment with the GnRH agonist, PETCO2 did not decline, and all women were free of symptoms.
Conclusion(s): The symptoms of PMS observed in our patients were associated with a pronounced decline of PETCO2 that occurred during the luteal phase of the cycle. Because the symptoms were similar to symptoms observed in the chronic hyperventilation syndrome it is suggested that some symptoms of PMS may be caused by chronic hyperventilation. It appears that in women with PMS the sensitivity of the respiratory center to CO2 is increased more than normal by P or some other secretory product of the corpus luteum, resulting in pronounced hyperventilation with the associated clinical signs and symptoms of a chronic hyperventilation syndrome.