Associations between maternal serum free beta human chorionic gonadotropin (β-hCG) levels and adverse pregnancy outcomes

Abstract

The objective was to determine the strength of relationship between maternal free beta human chorionic gonadotropin (β-hCG) concentrations and rates of adverse pregnancy outcomes. Consecutive records of the database of our Down screening project were assessed for free β-hCG levels and pregnancy outcomes. Pregnancies with foetal chromosomal or structural anomalies and those with underlying disease were excluded. Free β-hCG levels of < 0.5, > 0.5 and < 2.0, and ≥ 2.0 MoM were categorised as low, normal and high, respectively. Of 17,082 screened women, 13,620 were available for analysis. In the first trimester (n = 8150), low β-hCG levels significantly increased risk for intrauterine growth restriction (IUGR), preterm birth, low birth weight (LBW) and low Apgar score with relative risk of 1.66, 1.43, 1.83 and 2.89; whereas high β-hCG group had a significant decreased risk of preterm birth and GDM with relative risk of 0.73 and 0.62. In the second trimester (n = 5470), both low and high β-hCG groups had significant increased risks of the most common adverse outcomes, i.e. spontaneous abortion, IUGR and preterm birth. In conclusion, abnormally low (< 0.5MoM) or high (> 2.0 MoM) free β-hCG levels are generally associated with an increased risk of adverse pregnancy outcomes. Nevertheless, high free β-hCG levels in the first trimester may possibly decrease risk of preterm delivery and GDM.

Keywords::

• β-hCG
• adverse pregnancy outcomes
• maternal serum marker
• first trimester screening
• second trimester screening

Acknowledgements

We wish to thank the National Research University Project under Thailand’s Office of the Higher Education Commission and Diamond Research Grant of Faculty of Medicine, Chiang Mai University for financial support.

Declaration of interest: The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper.