Data from UK confidential enquiries suggest a declining rate of twin stillbirth in monochorionic (MC) and dichorionic (DC) twin pregnancies with improved outcomes possibly reflecting the establishment of national guidelines for the management of multiple pregnancies. Despite this, twin pregnancies are at greater risk of all pregnancy complications, miscarriage and stillbirth than singleton pregnancies. Monochorionic twins, comprising approximately 20% of twin pregnancies, are at particular risk of fetal loss due to the unique pathological complications of a shared placenta: Twin to Twin Transfusion Syndrome (TTTS), early-onset severe selective growth restriction (sGR) and twin anaemia polycythaemia sequence (TAPS). Furthermore, following single intrauterine fetal demise (sIUFD) surviving monochorionic co-twins are exposed to an increased risk of intrauterine death, neonatal death and neurological disability. This chapter examines single and double fetal loss in DC and MC twin pregnancies, outlining the key facts, and covering the difficult issues and management challenges posed by twin demise.

The claimant was the first twin and born by forceps delivery. At the time of the delivery, he suffered an intracerebral bleed, hydrocephalous and permanent neurological disability. It was claimed that the parents had informed the midwife they wished an elective caesarean section (CS) and there was a breach of duty in communicating this to the consultant in charge of her care. Had they been referred to the consultant, they would have asked for an elective CS which would have prevented the subsequent injury.

Structural fetal anomalies complicate up to 5% of pregnancies and an underlying chromosomal or genetic etiology underlies up to half of cases. Understanding the fetal genome is increasingly key in attempting to make a prenatal diagnosis and in delineating a prognosis for the baby. Over the past decades, the field of prenatal genomics has advanced exponentially, beginning with the conventional ‘full’ karyotype available in the 1960s and going up to the present day and beyond with the application of next-generation sequencing (NGS) (Figure 4.1). Current and potential future advances in prenatal diagnostics will allow couples to make more informed decisions prospectively about their pregnancies in addition to aiding decisions on and the development of fetal therapies [1]. In the wake of advancing technologies and large prospective studies such as the United Kingdom’s ‘proof of principle’ 100 000 Genomes Project [2] and the Prenatal Assessment of Genomes and Exomes (PAGE) study [3], the degree of information obtained and turnaround time of results with the development of more sophisticated bioinformatic analytical pathways is likely to improve rapidly. Fetal medicine subspecialists, obstetricians, pediatricians, geneticists, genomic scientists and genetic counselors have a responsibility to stay up to date with this wealth of advances so that couples can be informed accordingly.