Studies on aetiology , treatment options and obstetric outcome
- UNEXPLAINED INFERTILITY
OBJECTIVE To describe the current status of in-vitro fertilisation (IVF) and related technologies, including: the indications for the procedures and the problems associated with the use of stimulated cycles; the use of frozen embryos and donor eggs; and the newer procedures of gamete micromanipulation for male infertility, immature egg collection as a possible alternative to the stimulated cycle, and preimplantation genetic diagnosis. DATA SOURCES AND STUDY SELECTION The clinical experience and research at Monash IVF and the Centre for Early Human Development, Monash University, were reviewed in association with key original or review articles in the world literature. DATA SYNTHESIS Cumulative pregnancy rates for IVF and the gamete intrafallopian transfer (GIFT) procedure at Monash IVF demonstrate that 29% of IVF patients and 55% of GIFT patients will have a live baby, the average number of treatments pursued being 3.4. Analogues of gonadotrophin releasing hormone (GnRH) have improved pregnancy rates, reduced blood sampling, and prevented natural ovulation. Disadvantages of stimulated cycles include a higher risk of multiple pregnancy, a higher risk of hyperstimulation, and behavioural changes due to the effects of drugs. Natural cycles or immature egg collection at incidental laparoscopy may become alternatives to the use of the stimulated cycle. In Australia the GIFT procedure is more successful than IVF and is nearly always used if the fallopian tubes are normal. Multiple pregnancies may be reduced, particularly triplets, by reducing the number of eggs or embryos transferred to two when egg or embryo quality is high. Embryo freezing has made a small but important contribution to overall pregnancy rates by enabling patients to use excess eggs and embryos. The social and legal concerns resulting from the use of frozen embryos have required new ethical and legal considerations. Donor eggs have made a small contribution to achieving pregnancy in women with absent or inappropriate eggs and increased the chance of conception in women over the age of 40. Micromanipulation of sperm and eggs has enabled fertilisation and conception when sperm are defective in quantity or quality. Sampling of cells in early embryos enables genetic diagnosis and may be used in selecting chromosomally normal embryos in IVF procedures or in couples at risk of recessive genetic disease. CONCLUSION Assisted reproductive technology has developed over a decade to become useful for couples with infertility which cannot be cured by simpler treatments. The birth rates are comparable to natural conception and the incidence of congenital malformation is not increased. The costs and complexity of treatment have been reduced to in turn reduce the stress and social inconvenience of therapy. Problems related to the high risk of multiple pregnancy and the use of the stimulated cycle are being reduced and new techniques for severe male infertility and the detection of genetic abnormalities in the embryo are being introduced.