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Objectives: To describe the impact of rubella immunisation on the incidence of rubella, congenital rubella syndrome and rubella-related terminations of pregnancy in South Australia, and to identify factors associated with a re-emerging problem., Design and Methods: A population-based descriptive study using data from South Australian notifications of disease, births and terminations of pregnancy, the rubella immunisation programme, antenatal rubella antibody screening and paediatric hospital case records., Setting: South Australia (population 1.48 million people; 20,000 births per year)., Main Outcome Measures: Incidence of rubella (age-sex specific), congenital rubella syndrome and rubella-related terminations of pregnancy; antenatal rubella sero-positive rates; rubella immunisation uptake rates., Results: Rubella notification rates in 1990-1996 were significantly higher for males than females for ages 15-34 years. There were five cases of congenital rubella syndrome notified in 1980-1996 compared with at least 20 confirmed or compatible cases in 1965-1979. Rubella-related terminations of pregnancy are now rare, with the last termination for maternal rubella being in 1993. The antenatal rubella sero-positive rate in 1995 was 96.7%, but was significantly lower among Asian women born overseas (78.6% among those 30 years or older). Vaccination uptake rates in schoolgirls decreased between 1990 and 1994 (91.2% to 86.9%)., Conclusions: Since the introduction of rubella immunisation, the incidence of rubella infection among women of reproductive age, and of rubella-related terminations, has fallen. Congenital rubella syndrome has not been notified since 1990 but its risk persists with a recent increase in rubella notifications, a fall in school immunisation rates, a relatively low antenatal sero-positive rate among older Asian women born overseas and the trend towards giving birth at older ages. Effective immunisation programmes must be maintained, particularly in schools and for young children and migrant women.

Objective: To determine the prevalence of developmental dysplasia of the hip (DDH) in South Australia (SA) in 1991, the proportion of cases detected in the neonatal period and the perinatal risk factors for DDH., Methodology: Cases of DDH born in SA in 1991 were identified from multiple sources and their clinical data linked to perinatal data provided by midwives; five controls per case were obtained randomly from SA livebirths without congenital abnormalities and adjusted odds ratios (OR) for potential risk factors obtained by logistic regression analysis. South Australia perinatal data were also used to estimate numbers of births with perinatal risk factors for targeted screening., Results: Two hundred and six cases of isolated DDH were identified, giving a prevalence of 10.5 per 1000 births. Of these, 173 (84%) had been detected in the neonatal period. The perinatal risk factors for DDH were identified as breech presentation (OR 9.65), female babies (OR 4.04), first births (OR 1.91) and maternal age of 25 years or more (OR 1.53). Screening breech and firstborn female babies (23% of births) would yield approximately 51% of cases of DDH., Conclusions: Isolated DDH had a prevalence of 10.5 per 1000 births and 84% of cases had been detected in the neonatal period in SA. Repeated screening during infancy of "at risk' groups of babies is recommended.

Objective: To determine the sensitivity of antenatal screening methods for neural tube defects in population-based screening in South Australia in 1986-1991, and whether ultrasound can replace serum alpha-fetoprotein screening in terms of achieving an equivalent level of sensitivity., Design and Setting: Ascertainment of all births and terminations of pregnancy with neural tube defects from multiple sources for 1986-1991 in South Australia. Serum and amniotic fluid alpha-fetoprotein results were obtained from the only laboratory performing the tests as a Statewide antenatal screening programme, and information on ultrasound screening from case notifications, hospital case records and medical practitioners who cared for the women., Subjects: All 243 births and terminations of pregnancy with neural tube defects in South Australia in 1986-1991., Main Outcome Measures: The sensitivity of individual screening methods and of all methods used, particularly for spina bifida., Results: For pregnancies with neural tube defects screened by any method (serum alpha-fetoprotein, ultrasound or amniocentesis), 86% sensitivity was achieved. Ultrasound screening for anencephaly achieved 100% sensitivity even in low risk pregnancies, compared with 92% for serum alpha-fetoprotein. For spina bifida, the sensitivity of ultrasound screening increased with the level of risk in pregnancy: it was 60% in low risk pregnancies, which was equivalent to that of serum alpha-fetoprotein screening (64%); 89% in high risk pregnancies and 100% for women referred for confirmation of a suspected spina bifida by another ultrasonographer (chi 1(2) for trend = 23.49, P < 0.0001). Ultrasound screening in high risk pregnancies for spina bifida achieved higher sensitivity in teaching hospitals compared with other ultrasound services in the State (97% vs 65%), but sensitivity was equivalent for low risk pregnancies. It is estimated that, had the serum screening programme not been in place, the level of sensitivity achieved for spina bifida by ultrasound and amniocentesis would have been 62% compared with the actual situation of 76% with the programme in existence, a difference of nearly 15% (95% CI 2.5 to 26.7) (chi 1(2) = 5.45, P = 0.02)., Conclusions: Antenatal screening for neural tube defects in South Australia achieved a higher level of sensitivity with the maternal serum alpha-fetoprotein programme in place. We conclude that the serum screening programme should continue in South Australia pending a significant improvement in the sensitivity of routine ultrasound screening for spina bifida.