Originally Posted by chrisl137

Cabin pressure is typically around 25% below sea level pressure. If the source pressure hasn't changed (and it likely won't until she pumps), then the pressure difference between inside and outside has increased by 25% as the plane's altitude has increase. Larger pressure difference will lead to faster flow. I have no experience at all with the details of pumping, but it wouldn't surprise me at all if the change in cabin pressure caused discomfort that led to needing to pump, even if she had done so earlier near sea level.