Placental location and pregnancy outcome

The purpose of this study was to determine if placental location is associated with adverse pregnancy outcome and to assess whether any association exists between different blood groups and location of the placenta.

Medical records of women were reviewed retrospectively and placental position as documented in the case notes at routine antenatal (20-38 weeks) ultrasonography was identified. Placental position was categorised as anterior, posterior and fundal. Association of placental location with foeto-maternal outcome and different blood groups was noted.

A total 474 case notes of women were analysed for placental location, feto-maternal outcome and blood groups. Anterior placenta was found to have a relation with a greater risk of pregnancy-induced hypertension, gestational diabetes mellitus and placental abruption (p<0.001), while posterior placenta had a significant association with preterm labour (p<0.001). Regarding foetal outcome, an anterior placenta was significantly associated with intrauterine growth retardation and intrauterine foetal death (p<0.001). The majority (54%) of women with an anterior placenta were O-positive blood group, while 46% of women in the posterior placenta group were A-positive blood group (p<0.001).

Anterior placental implantation is associated with an increased risk of pregnancy-induced hypertension, gestational diabetes mellitus, placental abruption, intrauterine growth retardation and intrauterine foetal death. Posterior placenta has a significant association with preterm labour and A-positive blood group. Anterior placenta is common in women with O-positive blood group. Placental location may be an important determinant of pregnancy outcome.