For the borrowers, they have a 9 month term pregnancy, just like humans! Having a child is more dangerous, because instead of going to a hospital and getting help from a doctor, they have no pain medication and instead rely on a midwife, often a close friend that lives nearby, especially in America, where they’re spread out. In London, they do have more specialized trades, so there would be an actual midwife to help.
Wood sprites tend to have a slightly shorter term. Luckily, they have a strong community around them to help with the birth. In Wellwood, the new mother is usually led somewhere just outside the village when it’s time, and then once the baby is born and cleaned up they come back home. Mama rests and everyone holds the new baby sprout. Thank the Spirit that wood sprites are born with their wings all curled up!