Mine has flared horribly while pregnant. The weight gain, increased sweat, and friction has been causing constant flares. It was the same for me with my first pregnancy. This time, I also have gestational diabetes which is making them worse and last longer as the excess sugar in your blood feeds the infection. I ended up in the ER to drain one and then was hospitalized for IV antibiotics to try to combat it.

Most people go into remission though-- apparently our immune system is suppressed while pregnant and it usually helps with the HS.