The pattern of pregnancy loss in women with congenital uterine anomalies and recurrent miscarriage.

Congenital uterine anomalies (CUA) are a known cause of recurrent miscarriage (RM), but the pattern of pregnancy loss that different CUA produce remains unknown. This study included 665 women with RM who were screened for CUA using a combined two-dimensional ultrasound (2D-US) and hysterosalpingography (HSG) approach. All suspected CUA were definitively diagnosed and classified via a combined hysteroscopy/laparoscopy procedure. Pregnancy outcomes were evaluated and compared for each type of CUA versus a control group of women with no identifiable cause of RM (unexplained RM). Fifty-six women with CUA and 107 women with unexplained RM were identified. In total, 881 pregnancies were analysed. Analysis showed that women with a septate or bicornuate uterus suffered from significantly increased second-trimester miscarriages compared with controls (13.2% and 13.8% versus 1.0%; P<0.001 and P<0.05, respectively). Women with an arcuate, septate or bicornuate uterus showed significantly reduced rates of biochemical pregnancy losses compared with controls (9.5%, 11.1% and 11.1% versus 30.4%; P<0.01, P<0.01 and P<0.05, respectively). Pregnancies of women with RM and CUA are not associated with early implantation failure and are compromised at a more advanced gestational age.