Triplets and quadruplets born in Victoria between 1982 and 1990. The impact of IVF and GIFT on rising birthrates.

OBJECTIVES

To examine the perinatal characteristics of all higher order multiple births (133 sets of triplets and six sets of quadruplets) in the State of Victoria between 1982 and 1990. To compare the rising higher order multiple birth rates in Victoria with those in the other States of Australia, and to assess the impact of in-vitro fertilisation (IVF) and gamete intrafallopian transfer (GIFT) on these rising birth rates.

DESIGN

Retrospective review of all higher order multiple births registered in Victoria and other States of Australia between 1982 and 1990, and in particular those resulting from IVF and GIFT.

DATA SOURCES

Victorian Perinatal Data Collection Unit, Australian Bureau of Statistics, National Perinatal Statistics Unit, data from Victorian IVF and GIFT units.

MAIN OUTCOME MEASURES

Higher order multiple birth rates and perinatal mortality rates.

RESULTS

The higher order multiple birth rates in Victoria rose from 3.5 per 10,000 in 1982 to 10.9 per 10,000 in 1990. The average perinatal mortality rates for the Victorian triplets and quadruplets born during this period were 10.8% and 25.0%, respectively. The rates of caesarean section were 70% and 83%; the proportions of deliveries in level III hospitals, 75% and 100%; and the mean maternal lengths of stay in hospital, 32 and 57 days, respectively. Endotracheal intubation was performed at birth in 18.5% of all infants. The proportions of triplet and quadruplet pregnancies in Victoria owing to IVF and GIFT rose during this period, reaching a peak of 42% in 1990. In the other States, the birth rates for higher order multiples increased at 1.8 times the rate observed for Victoria, with IVF and GIFT contributing to an estimated 43% of these conceptions between 1985 and 1989.

CONCLUSION

Restrictions on the numbers of embryos/oocytes transferred during IVF and GIFT should reduce the frequency of higher order multiple births.