While some use the term 'polymorphic eruption of pregnancy' to cover these, this term is a synonym used in the UK for Pruritic urticarial papules and plaques of pregnancy, which is the commonest of these skin conditions.
Some people refer to these as a 'polymorphic eruption of pregnancy,' although this phrase is actually a British term that corresponds to Pruritic urticarial papules and plaques of pregnancy, which is the most common of these skin disorders.