Assisted conception, Australia and New Zealand 1996

Assisted conception, Australia and New Zealand 1996 is the third report on the use of assisted reproduction technology (ART) in Australia and New Zealand.

Highlights

• In Australia, infertile couples were treated by in-vitro fertilisation (IVF) and gamete intrafallopian transfer (GIFT) in 27 units in 1996. New Zealand had 6 IVF units in this period. There were 2,920 births after assisted conception in Australia in 1995, accounting for 1.1% of all births. In New Zealand, there were 175 births after assisted conception in 1995.
• When all techniques of assisted conception are included together, the viable pregnancy rate in 1996 was 14.4 per 100 embryos transfer cycles, indicating that 1 in 7 treatment cycles reaching the stage of embryo transfer resulted in a viable pregnancy of 20 weeks or more.
• In 1996, after transfer of fresh embryos to the uterus, the viable pregnancy rate was 11.9 per 100 oocyte retrieval cycles. After GIFT, the viable pregnancy rate was 22.0 per 100 oocyte retrieval cycles. After embryo freezing, the viable pregnancy rate was 11.1 per 100 embryo transfer cycles.
• There has been a marked increase in treatment cycles in which intracytoplasmic sperm injection (ICSI) was attempted. Oocyte retrieval cycles for microinsemination increased from 1,243 in 1993 to 2,786 in 1994, 4,261 in 1995, and 5,271 in 1996. With an additional 2,297 embryo transfer cycles after microinsemination and embryo freezing in 1996, microinsemination accounted for 35.1% of all assisted conception cycles in that year. The overall proportion of assisted conception pregnancies resulting from ICSI and other types of microinsemination increased rapidly from less than 1 in 200 (0.4%) in 1990 to more than 1 in 4 (28.8%) in 1995.
• The viable pregnancy rate for ICSI and transfer of fresh embryos was 13.7 per 100 oocyte retrieval cycles in 1996. For cycles after ICSI and embryo freezing, the viable pregnancy rate was 11.1 per 100 embryo transfer cycles in 1996.
• Between 1995 and 1996, there were increases in the proportion of cycles with more than 3 embryos or oocytes transferred. For all IVF, more than 3 embryos were transferred to the uterus in 1.9% of cycles in 1995 and in 2.8% of cycles in 1996; for GIFT, more than 3 oocytes were transferred in 5.6% of cycles in 1995 and in 7.2% of cycles in 1996.
• The multiple pregnancy rate varied markedly between IVF units. In the combined years of 1993-1995, the multiple pregnancy rate for all types of assisted conception ranged from 6.6% to 29.4%. During this same period, multiple pregnancy occurred in 1 in 5 (19.9%) of all IVF and GIFT pregnancies. In IVF pregnancies, twins increased from 15.1% in 1994 to 17.7% in 1995, triplets occurred in 1.6% in 1994 and 1.7% in 1995, and there was 1 quadruplet pregnancy in 1994. In GIFT pregnancies, twins decreased from 22.0% in 1994 to 20.0% in 1995; triplets decreased from 3.9% in 1994 to 2.7% in 1995; and there were 2 quadruplet pregnancies in 1994 and 1 in 1995.
• In 1995, 46 (59.0%) of 78 perinatal deaths after IVF, and 12 (63.2%) of 19 perinatal deaths after GIFT, occurred in multiple births.
• Among 1,727 IVF pregnancies after ICSI between 1990 and 1995, live births occurred in 77.2%, spontaneous abortion in 19.0%, and ectopic pregnancy in 1.8%. Twins occurred in 16.8% of viable pregnancies, triplets in 1.7%, and there was one quadruplet pregnancy. Among 1,630 ICSI births, the perinatal death rate was 34.4 per 1,000 births; for singleton births, it was 19.9 per 1,000 births; for twins, 59.5 per 1,000 births; and for triplets, 101.4 per 1,000 births. Congenital malformations were reported in 51 (3.1%) fetuses and infants after ICSI, similar to the overall rate in IVF births.