Prostaglandins are a class of lipids, that are secreted in the event of an injury, tissue damage or contraction. They're said to occur in almost every human organ. Contraction simply put, is when the inner muscles, the uterine begins to tighten and release at intervals during or before child-birth. So prostaglandins in this case helps to cause these contractions to occurr. it does this by also softening the cervix, making it ready for contraction.
I would do a mountain bike personally, its tougher but If you want to do mountain biking then you're going to need something like that. Mountain bikes have great tires and last a long time. Try Dicks sporting goods or any place like that. But if you want a more comfortable bike then I would look into something that allows you to change the gears of the bike.
