PRENATAL DIAGNOSIS Prenat Diagn 2004; 24: 596–604. Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/pd.908 Congenital malformations of the diaphragm: findings of the West Midlands Congenital Anomaly Register 1995 to 2000 A. Tonks 1 , M. Wyldes 1 , D. A. Somerset 2 *, K. Dent 1 , A. Abhyankar 3 , I. Bagchi 3 , A. Lander 3 , E. Roberts 4 and M. D. Kilby 2 1 West Midlands Perinatal Institute, Birmingham, UK 2 Department of Fetal Medicine, University of Birmingham, Birmingham Women’s Hospital, UK 3 Institute of Child Health & Department of Paediatric Surgery, University of Birmingham, Birmingham Children’s Hospital, UK 4 Regional Genetics Laboratories, Birmingham Women’s Hospital, UK Objectives To describe trends in incidence, associated anomalies, clinical outcomes and sensitivity of prenatal diagnosis for congenital malformations of the diaphragm in the West Midlands Region between 1995 and 2000. Methods Information was retrieved from a population-based register of major congenital malformations in a health region of England, the West Midlands Congenital Anomaly Register (WMCAR), between 1995 and 2000. Results One hundred and sixty-one confirmed cases of congenital malformations of the diaphragm were notified from 396 577 births. This gives an incidence of 4.1 per 10 000 births. After natural losses and terminations, the incidence at birth was 2.9 per 10 000 registered births. For live-born cases, the infant mortality rate was 317 per 1000 births. 47% of the cases had additional structural or chromosomal anomalies; the infant mortality rate for these complex cases was 533 per 1000, an increased relative risk of 2.37 compared with isolated lesions. 66% of the cases were diagnosed prenatally, 51% of isolated lesions and 84% of complex cases. Fourteen prenatally diagnosed cases (12%) were false-positives; however, 11 of these cases had other significant pathology. These 14 cases were not included in the 161 confirmed cases. Conclusion Congenital malformations of the diaphragm remain associated with considerable infant mortality. Most cases are now diagnosed before birth and the prognosis is adversely affected by the presence of other structural or chromosomal anomalies. This presents significant challenges for those involved in counselling the parents of affected fetuses. Copyright  2004 John Wiley & Sons, Ltd. KEY WORDS: congenital diaphragmatic hernia; karyotype; mortality; outcome; prenatal diagnosis INTRODUCTION Congenital malformations of the diaphragm are reported to occur in between three and five per 10 000 births and may be diagnosed before birth by high-resolution ultrasound (Dillon and Renwick, 1993; Harrison and de Lorimier, 1981; Leck et al., 1959). We had previ- ously reported on the outcome for cases of congen- ital diaphragmatic hernia diagnosed prenatally at our regional Fetal Medicine unit between 1988 and 1995 (Howe et al., 1996). Our earlier study showed that the survival for isolated malformations diagnosed prena- tally was 50%, and that the coexistence of other struc- tural or chromosomal anomalies was a poor prognostic indicator, with survival reduced to 20%. These figures were much worse than contemporary survival rates reported from paediatric surgical centres and empha- sised the importance of having data from prenatally diagnosed case series when counselling parents follow- ing prenatal diagnosis of congenital malformation of the diaphragm. *Correspondence to: Dr D. A. Somerset, Department of Fetal Medicine, University of Birmingham, Birmingham Women’s Hospital, B15 2TG, UK. E-mail: d.a.somerset@bham.ac.uk In this study, we report on the incidence, diagnosis and outcome for all cases of congenital malformation of the diaphragm in the West Midlands Region notified over a six-year period to the regional Congenital Anomaly Register, which was first established in June 1994. In addition, we report ongoing mortality during the first post-natal year. METHODS The West Midlands Congenital Anomaly Register (CAR) was set up in June 1994 and is administered by the West Midlands Perinatal Institute. The register collects information on the occurrence of suspected and con- firmed congenital anomalies of West Midlands residents, detected before and after birth. Notifications are received at the register by three methods. The first method is a notification card, which is used to notify the regis- ter of suspected anomalies. The card includes details of the type of anomaly and the estimated date of delivery; it is most often completed by ultrasound departments. The second method is through an obstetric notification form, which contains much of the data set used for the confidential enquiry into stillbirths and deaths in infancy (CESDI) but has additional details relating to the Copyright  2004 John Wiley & Sons, Ltd. Received: 24 October 2003 Revised: 2 March 2004 Accepted: 31 March 2004