Impact of location on placentation in live tubal and cesarean scar ectopic pregnancies.

Introduction: The objective of this study was to evaluate the impact of implantation outside the normal intra-uterine endometrium on development of the gestational sac.

Methods: We reviewed and compared the ultrasound measurements and vascularity score around the gestational sac in 69 women diagnosed with a live tubal ectopic pregnancy (TEP) and 54 with a cesarean scar ectopic pregnancy (CSP) at 6-11 weeks of gestation who were certain of their last menstrual period.

Results: The rate of a fetus with a cardiac activity in the study population was significantly (P < 0.001) higher in CSPs than in TEPs. The median maternal age, gravidity and parity were significantly (P =.005; P < 0.001 and P < 0.001, respectively) lower in the TEP than in the CSP group. The number of gestational sac size <5th centile for gestational age was significantly (P < 0.001) higher in the TEP than in the CSP group. There were no differences between the groups for the other ultrasound measurements. In cases matched for gestational age, the gestational sac size was significantly (P < 0.001) smaller in the TEP compared to the CSP group. There was a significant (P < 0.001) difference in the distribution of blood flow score with CSP presenting with higher incidence of moderate and high vascularity than TEP.

Discussion: Both TEP and CSP are associated with a higher rate of miscarriage than intrauterine pregnancies and the slow development of the gestation sac is more pronounced in TEPs probably as a consequence of a limited access to decidual gland secretions.