Abstract
Abstract Triplets and quadiplets still have a higher morbidity and mortality rate than the rest of the population. The purpose of the study was to examine possible causes for the high occurrence of high order multiple pregnancies (HOMPs) in the two maternity wards at Oslo University Hospital (OUS) between January 1st 2000 and July 1st 2015, and if possible find strategies to reduce their incidence. To find the probable causes I went through all the patient records of all HOMPs delivered in the two maternity wards at OUS in this period. Data regarding gestation age, birth weight and peri- and neonatale complications were also registered. A total of 89 HOMPs occurred, 84 triplets and 5 quadruplets. In 12 pregnancies in the period 2000-2001 there was no information recorded regarding the mode of conception. In the HOMPs examined 24,7% (22/89) were spontaneous, 25,8% (23/89) resulted from hormonal stimulation either with Clomiphene or gonadotrophins, 27,0% (24/89) followed lVF/ICSI treatment (in-vitro fertilisation, intracytoplasmic sperm injection) and in 22,5% (20/89) the cause was unknown. Most likely a significant amount of HOMPs is a result of multiple embryos transferred with IVF/ICSI, and it is still important to continue work towards reducing the number of embryos transferred to reduce the incidence of HOMPs. There is also probably a high share of IVF/ICSI done abroad resulting in HOMPs where the number of embryos transferred is unknown. Hormonal stimulation of the ovaries without IVF resulted in a quarter of the HOMPs examined. Better monitoring of this treatment and systematic registration could contribute to reducing the incidence of HOMPs.