Depending on where you go for your pre-pregnancy checkups - you may or may not be offered an ultrasound. If the discrepancy is small an ultrasound may not pick up a short femur.
If you are having a child with PFFD and the ultrasound picks up a short femur(s) - it is nice to have found out ahead of time. It really helps to have prepared yourself for dealing with the hospital/staff at delivery. (More about that later). If the ultrasound does pick up a shorter femur - the technician or doctor should also have looked for other possible defects such as cleft lip, cardiovascular abnormalities, single umbilical cord artery, etc. The reason they look for the other items is because a short femur plus those other effects can mean something besides PFFD.
In one parents' case (let's call them the X's) the technician picked up one femur shorter than the other, however, doctor reviewing the ultrasound did not know anything about PFFD and said "it is too bad you found out so late because now it's too late to do anything about it." (E.g. abortion) This of course completely traumatized the X's until they got the facts about PFFD. After learning about PFFD they came to the conclusion that PFFD is no big deal.
If the diagnosis is PFFD then relax and enjoy your pregnancy as you would any other one. There isn't anything for you to do at this point differently than you'd do for a regular pregnancy. You will still feel the baby kick and punch and move in relation to sounds, voices etc. The fact is that PFFD has no relation to the development of the other parts of the baby (brain, heart, etc.). (See [[Etiology (What causes it?)]] ) After the ultrasound you may be offered a consult with an orthopaedic surgeon perhaps even one who specializes in pediatrics. It’s a good idea to do that. It gives you an opportunity to meet with someone and talk about what to expect.
In any case, get ready for a baby who is every bit as wonderful as you'd expect, but with one leg shorter than that other if it is unilateral PFFD or potentially both legs shorter with bilateral PFFD.