Role of fertility treatments in multiple pregnancy at National Women's Hospital from 1996 to 2001

Objective: To determine the influence of fertility treatments on multiple pregnancy rates. Study Design: A retrospective audit of women with multiple pregnancies from 1996 to 2001 at National Women's Hospital (NWH), Auckland, New Zealand was conducted. Information was collected regarding the demographics, fertility treatment, outcome of the pregnancy and complications experienced by women discharged with multiple births as an discharge diagnosis. Results: For the years 1996-2001 there were 1136 multiple births at NWH. Of these births, 201 (18%) were conceived following fertility treatment. Seventeen percent of twin births and 44% of triplet births were conceived following fertility treatment. There was a statistically significant increase in the number of births conceived following fertility treatment, from 9% in 1996 to 24% in 2001, although the proportion of births that were multiple overall did not change (2% in 1996 and 2.3% in 2001). Sixty-three percent of all fertility conceived multiple births were following in vitro fertilization/intracytoplasmic sperm injection treatment. Sixty percent of these women had two embryos transferred and 31% had three embryos transferred. Ovulation induction with follicle-stimulating hormone accounted for 19% of all fertility conceived multiple births. Nineteen percent of fertility conceived multiple births followed clomiphene treatment alone. Conclusions: The proportion of multiple pregnancies as a result of fertility treatments has increased over the 6 years studied.