How common is PG?
Pretty rare. It has been estimated to affect 2 out of every 100,000 pregnancies. There is also a racial difference with Caucasians being more affected than black women.
Is that every skin condition in pregnancy?
Unfortunately not. There are a score more skin disorders which are less common but distinct conditions. In fact, don't be surprised if you have symptoms of a skin condition and your obstetrician throws his or her hands up in despair, out of ignorance. When the diagnosis is not obvious, as is sometimes the case, your obstetrician will liaise with the skin specialist to try to identify the condition and then begin the required treatment.
Should one worry if there is no specific diagnosis?
In general, no. The important issue is to exclude the conditions that may have undesirable effects on the pregnancy. Once this is established and the only complaint is itching, control of the symptoms is all that is required. The disappointment is usually that the normal symptom control measures with all sorts of fancy and not-so-fancy names are hardly ever effective.