Differences in Sex Development (DSD) is an umbrella term which covers conditions arising from a difference in observed and expected sex development. This could include karyotype, gonadal tissue, or genital appearance. Previously alternative terms were used, such as intersex, pseudo-hermaphrodite and testicular feminisation, but these were inaccurate and generally disliked by patients. A consensus was reached in 2006 to change the terminology to disorders of sex development, with individual conditions referred to by their genetic basis [1]. This has been largely accepted in the medical literature, with older more pejorative terms falling from use. Whilst more accurate, the term DSD has not been without its critics, and there is a move towards describing this group of conditions as differences in sex development, which would seem to fit more appropriately with the increased understanding in anatomical variance in those with no known medical condition.

Complications arise more frequently during the first trimester than at any other stage of pregnancy. Most present with bleeding, pain, or both. Vaginal bleeding occurs in about 20% of clinically diagnosed pregnancies. It causes considerable anxiety for the woman and her partner. In the vast majority of cases, no intervention alters the outcome. The main aim of clinical management is a prompt and accurate diagnosis, with reassurance if the pregnancy is appropriately developed and viable, or appropriate intervention if not. This chapter focuses on the principles of diagnosis and management and three principal diagnoses: miscarriage, ectopic pregnancy, and gestational trophoblastic disease. The other differential diagnoses are shown in Table 5.1.