Possibility of live birth in patients with low serum \u03b2-hCG 14\u2009days after blastocyst transfer

Yixuan Wu,Haiying Liu

doi:10.1186/s13048-020-00732-6

Abstract

BackgroundAlthough prior work has attempted to predict pregnancy outcomes by assaying serum β-hCG levels after blastocyst transfer, no study has focused on pregnancy outcomes in those with initially low serum β-hCG levels. This study sought to investigate pregnancy outcomes of patients with low serum β-hCG levels 14 days after blastocyst transfer.MethodsA retrospective study was conducted at the Third Affiliated Hospital of Guangzhou Medical University to study patients whose serum β-hCG levels were at 5–299 mIU/ml 14 days after frozen blastocyst transfer. Rates of live birth, early miscarriage, biochemical pregnancy loss and ectopic pregnancy were analyzed according to the female patients’ age by Chi-squared analysis. Receiver operating characteristic (ROC) curves were plotted to explore the threshold of predicting clinical pregnancy and live births.Results312 patients had serum β-hCG levels < 300 mIU/ml at 14 days after frozen blastocyst transfer, among which, 18.6% were live births, 47.4% were early miscarriages, 22.8% were biochemical pregnancies and 9.6% were ectopic pregnancies. ROC curve analysis showed that a predicted value of β-hCG for clinical pregnancy was 58.8 mIU/ml with an area under the ROC curve (AUC) of 0.752, a sensitivity of 95.0% and specificity of 53.5%. The threshold for live births was 108.6 mIU/ml with an AUC of 0.649, a sensitivity of 93.1% and a specificity of 37.0%. For the β-hCG fold increase over 48 h, the cut-off for clinical pregnancy was 1.4 with an AUC of 0.899, a sensitivity of 90.3% and a specificity of 77.8%. The threshold for live birth was 1.9 with an AUC of 0.808, a sensitivity of 88.5% and specificity of 64.5%.ConclusionsInitially low serum β-hCG levels 14 days after frozen blastocyst transfer indicated minimal chances of live birth. For patients having an initial β-hCG > 58.8 mIU/ml, luteal phase support should continue. Another serum β-hCG test and ultrasound should be performed one week later. When an initial serum β-hCG is < 58.8 mIU/ml, luteal phase support should be discontinued and serum β-hCG measured with ultrasound one week later.

Highlights

Human chorionic gonadotropin is secreted by syncytiotrophoblasts at the time of implantation. Since it is detected in maternal serum as soon as 6–8 days after fertilization, β-hCG is widely used in the clinic as a marker of pregnancy
Our study showed that pregnancy outcomes of the patients with initially low serum β-hCG levels were poor, with only 18.6% of live births
Our study demonstrated that the initial β-hCG value > 58.8 mIU/ml predicted 85.8% of clinical pregnancies, while a failure to achieve that value led to 73.3% of biochemical pregnancy loss

Summary

Introduction

Human chorionic gonadotropin (hCG) is secreted by syncytiotrophoblasts at the time of implantation. Since it is detected in maternal serum as soon as 6–8 days after fertilization, β-hCG is widely used in the clinic as a marker of pregnancy. In fresh embryo transfer cycles, the thresholds of serum β-hCG levels to predict clinical pregnancy and live births were 111–213 IU/L and 160– 222.8 IU/L respectively 10–12 days after transfer [2,3,4,5,6,7]. This study sought to investigate pregnancy outcomes of patients with low serum β-hCG levels 14 days after blastocyst transfer

Methods

Results

Discussion

Conclusion