Prevalence and risk factors for obstetric haemorrhage in 6730 singleton births after assisted reproductive technology in Victoria Australia.

BACKGROUND: Obstetric haemorrhages have been reported to be increased after assisted reproduction technologies (ART) but the mechanisms involved are unclear.
METHODS: This retrospective cohort study compared the prevalence of antepartum haemorrhage (APH), placenta praevia (PP), placental abruption (PA) and primary post-partum haemorrhage (PPH) in women with singleton births between 1991 and 2004 in Victoria Australia: 6730 after IVF/ICSI, 24 619 from the general population, 779 after gamete intrafallopian transfer (GIFT) and 2167 non-ART conceptions in infertile patients. Risk factors for haemorrhages in the IVF/ICSI group were examined by logistic regression.
RESULTS: The IVF/ICSI group had more APH: 6.7 versus 3.6% (adjusted OR 2.0; 95% CI 1.8-2.3), PP: 2.6 versus 1.1% (2.3; 1.9-2.9), PA: 0.9 versus 0.4% (2.1; 1.4-3.0) and PPH: 11.1 versus 7.9% (1.3; 1.2-1.4) than the general population. APH, PP and PA were as frequent in the GIFT group as in the IVF/ICSI group, but were less frequent in the non-ART group. Within the IVF/ICSI group, fresh compared with frozen thawed embryo transfers (FET) was associated with more frequent APH (1.5; 1.2-1.8) and PA (2.1; 1.2-3.7) and the odds ratio increased with number of oocytes collected (1.02; 1.00-1.04). Endometriosis patients had more PP (1.7; 1.2-2.4) and PPH (1.3; 1.1-1.6) than those without endometriosis. FET in artificial cycles was associated with increased PPH (1.8; 1.3-2.6) compared with FET in natural cycles.
CONCLUSIONS: Obstetric haemorrhages are more frequent with singleton births after IVF, ICSI and GIFT. The exploratory analysis of factors in the IVF/ICSI group, showing associations with fresh embryo transfers in stimulated cycles, endometriosis and hormone treatments, suggests that events around the time of implantation may be responsible and that suboptimal endometrial function is the critical mechanism.