Serum β‐human chorionic gonadotropin profile and its correlations with ultrasound parameters in low‐lying‐implantation ectopic pregnancy in the first trimester

AIM: Cervical pregnancy (CP) and cesarean scar pregnancy (CSP), defined as low-lying-implantation ectopic pregnancy (LLIEP), are rare conditions of aberrant implantation around the lowest portion of the uterus. This study aimed to illustrate the serum beta-human chorionic gonadotropin (beta-hCG) profile of LLIEP and to explore its implications with the clinical characteristics. METHODS: Women with LLIEP during the first trimester were retrospectively evaluated at a tertiary referral center from August 1999 to July 2016. Demographic and clinical data were recorded, including maternal age, gestational age (GA), serum beta-hCG level, maximal diameter of the gestational mass/sac (MDM/MDS) by ultrasonography and CSP implantation types. The serum beta-hCG level was measured on the day of ultrasound imaging. The significance of pretreatment the serum beta-hCG level and its correlations with the clinical characteristics were analyzed. RESULTS: A total of 88 LLIEP with 64 CSP and 24 CP was included. The mean GA at the time of diagnosis was 7 weeks (range, 5-12 weeks). The beta-hCG concentrations rapidly increased from GA 5 to 9 weeks and fluctuated thereafter. The beta-hCG levels correlated positively with GA and ultrasound MDM/MDS. In the CSP group, there was no difference in the beta-hCG level between superficial and deep implantation types. beta-hCG levels demonstrated no significant differences among simple and complicated LLIEP. CONCLUSION: This study established the serum beta-hCG profile in LLIEP in the first trimester. The exponential increase of beta-hCG levels was similar to that of normal intrauterine pregnancies. The beta-hCG levels were not associated with placentation complexity of CSP. Higher beta-hCG levels did not implicate less success in conservative surgical management.