At the close of this century of immense technological advance there is still debate about how best to determine when confinement is due and whether widely available technology for this should be used for all pregnant women or not. The expected date of delivery (EDD) is a central point in antenatal care. Without accurate knowledge of gestational length the evaluation of fetal wellbeing and fetal growth, as well as the timing of delivery, is bound to be difficult. No one who remembers the uncertainities surrounding gestational age assignment in the time before the advent of modern ultrasound wishes a return to those times, anymore than it is unthinkable that the telephone, televison, microwave owens, fridges, calculators or computers can be dispensed with from our lives. No one would start a flight today without using the necessary electronic devices to enable safe flying, although this may have been done fifty years ago. It may then seem strange that ultrasonic measurements of the fetus, which enable gestational length to be assessed with good accuracy, should not be universally accepted. The last menstrual period (LMP) is still widely preferred for assigning gestational age, even where there is free access to modern ultrasound.

During pregnancy there are profound metabolic, endocrine and vascular changes which are tolerated for a short period of time. As the skin represents the largest organ of the body, these changes are also reflected in the appearance of the skin both by the improvement or exacerbation of pre-existing skin disease and by the development of new dermatoses. The specific dermatoses of pregnancy are a group of disorders which only occur in the pregnant state.

This review will discuss the physiological effects of pregnancy on the appearance and function of normal skin, and other cutaneous diseases affected by pregnancy (including intrahepatic cholestasis). The latter part of the review will discuss important aspects of the specific dermatoses of pregnancy.

Genital herpes infection remains a difficult problem to manage during pregnancy. The natural history of the infection during pregnancy is not well understood and potential management strategies remain unevaluated. For example the risk of mother-to-child transmission in women with recurrent genital herpes lesions at the time of vaginal delivery is still unknown. We do not know whether delivery by caesarean section decreases this risk and yet it is the most widely used intervention in this situation. We are only just beginning to understand the epidemiology of asymptomatic infection and the risk that asymptomatic viral shedding may pose to the newborn. In addition, new methods of diagnosis and new strategies for management are regularly being proposed with little formal evaluation of their effectiveness in the clinical setting.

This article aims to review current knowledge applicable to the clinical situation and suggest how our knowledge and management of this problem may be improved in the future.