Elevated second-trimester free beta-hCG as an isolated finding and pregnancy outcomes

The association between human chorionic gonadotropin and adverse pregnancy outcomes: a systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the association between human chorionic gonadotropin and adverse pregnancy outcomes.

DATA SOURCES

Medline, Embase, PubMed, and Cochrane were searched in November 2021 using Medical Subject Headings (MeSH) and relevant key words.

STUDY ELIGIBILITY CRITERIA

This analysis included published full-text studies of pregnant women with serum human chorionic gonadotropin testing between 8 and 28 weeks of gestation, investigating fetal outcomes (fetal death in utero, small for gestational age, preterm birth) or maternal factors (hypertension in pregnancy: preeclampsia, pregnancy-induced hypertension, placental abruption, HELLP syndrome, gestational diabetes mellitus).

METHODS

Studies were extracted using REDCap software. The Newcastle-Ottawa scale was used to assess for risk of bias. Final meta-analyses underwent further quality assessment using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) method.

RESULTS

A total of 185 studies were included in the final review, including the outcomes of fetal death in utero (45), small for gestational age (79), preterm delivery (62), hypertension in pregnancy (107), gestational diabetes mellitus (29), placental abruption (17), and HELLP syndrome (2). Data were analyzed separately on the basis of categorical measurement of human chorionic gonadotropin and human chorionic gonadotropin measured on a continuous scale. Eligible studies underwent meta-analysis to generate a pooled odds ratio (categorical human chorionic gonadotropin level) or difference in medians (human chorionic gonadotropin continuous scale) between outcome groups. First-trimester low human chorionic gonadotropin levels were associated with preeclampsia and fetal death in utero, whereas high human chorionic gonadotropin levels were associated with preeclampsia. Second-trimester high human chorionic gonadotropin levels were associated with fetal death in utero and preeclampsia.

CONCLUSION

Human chorionic gonadotropin levels are associated with placenta-mediated adverse pregnancy outcomes. Both high and low human chorionic gonadotropin levels in the first trimester of pregnancy can be early warning signs of adverse outcomes. Further analysis of human chorionic gonadotropin subtypes and pregnancy outcomes is required to determine the diagnostic utility of these findings in reference to specific cutoff values.

The Effect of Serum β-Human Chorionic Gonadotropin on Pregnancy Complications and Adverse Pregnancy Outcomes: A Systematic Review and Meta-Analysis

Background

The relationship among elevated serum β-human chorionic gonadotropin (β-hCG), the incidence of pregnancy complications, and adverse pregnancy outcomes has been controversial. Differences in study design, subject bias due to demographic characteristics, and differences in local medical levels could contribute to inconsistent results.

Methods

Literature searches were performed in PubMed, EMBASE, Medline, Central, China National Knowledge Infrastructure (CNKI), Wanfang, and China Science Digital Library (CSDL) databases. Inclusion criteria were as follows: (1) research subjects were singleton pregnant women; (2) the study is identified as cohort study; (3) the subjects were assigned to the high β-hCG group and control group according to whether the exposure factors increased β-hCG in the second trimester; (4) the observed outcomes include at least pregnancy-induced hypertension (PIH), diabetes (gestational diabetes mellitus, GMD), preterm delivery (PD), and intrauterine growth restriction (IUGR); and (5) the odds ratio (OR) and 95% confidence interval (CI) of exposure factors are calculated based on literature dataset. To determine the risk bias of selected literatures, Newcastle-Ottawa scale was applied. The chi-square test was further used for heterogeneity analysis. If heterogeneity was identified, subgroup analyses were then performed for source investigation.

Results

A total of 13 literatures were included and analyzed, including 67,355 pregnant women and 5980 pregnant women assigned to the high β-HCG group and 61,375 pregnant women to the control group. The incidence of PIH in the high β-HCG group was higher than that in the control group (OR = 2.11, 95% CI [1.90, 2.35], Z = 13.85, P < 0.00001). There was no heterogeneity among literatures (χ² = 8.53, P = 0.38, I² = 6%), and thus there is no identified publication bias (P > 0.05). The incidence of preterm birth in the high β-HCG group was higher than that in the control group (OR = 2.11, 95% CI [1.90, 2.35], Z = 13.85, P < 0.00001). The analysis suggested no heterogeneity among included literatures (χ² = 11.78, P = 0.11, I² = 41%) and no publication bias (P > 0.05). Higher incidence of abortion was observed in the high β-HCG group compared with the control group (OR = 2.80, 95% CI [1.92, 4.09], Z = 5.32, P < 0.00001). There was no heterogeneity among literatures (χ² = 3.43, P = 0.33, I² = 13%) and no publication bias (P > 0.05). The incidence of gestational diabetes was higher in the high β-HCG group than in the control group (OR = 2.15, 95% CI [1.05, 4.40], Z = 2.09, P = 0.04). Heterogeneity was identified among literatures (χ² = 47.01, P < 0.00001, I² = 87%). Sensitivity analysis showed that the results were not robust, and there was no publication bias (P > 0.05). Compared with control, the incidence of IGUR was higher in the high β-HCG group (OR = 2.70, 95% CI [1.75, 4.19], Z = 4.45, P < 0.0001) with no heterogeneity among literatures (χ² = 3.92, P = 0.14, I² = 49%) and no publication bias (P > 0.05).

Conclusion

High levels of β-hCG during pregnancy in singleton women are associated with a high incidence of pregnancy complications and adverse pregnancy outcomes. Pregnant women with high levels of β-hCG should be monitored more closely, followed up, and given timely medical interventions to reduce the incidence of pregnancy complications and adverse outcomes.

Serum screening with Down's syndrome markers to predict pre-eclampsia and small for gestational age: systematic review and meta-analysis

Background

Reliable antenatal identification of pre-eclampsia and small for gestational age is crucial to judicious allocation of monitoring resources and use of preventative treatment with the prospect of improving maternal/perinatal outcome. The purpose of this systematic review was to determine the accuracy of five serum analytes used in Down's serum screening for prediction of pre-eclampsia and/or small for gestational age.

Methods

The data sources included Medline, Embase, Cochrane library, Medion (inception to February 2007), hand searching of relevant journals, reference list checking of included articles, contact with experts. Two reviewers independently selected the articles in which the accuracy of an analyte used in Downs's serum screening before the 25^th gestational week was associated with the occurrence of pre-eclampsia and/or small for gestational age without language restrictions. Two authors independently extracted data on study characteristics, quality and results.

Results

Five serum screening markers were evaluated. 44 studies, testing 169,637 pregnant women (4376 pre-eclampsia cases) and 86 studies, testing 382,005 women (20,339 fetal growth restriction cases) met the selection criteria. The results showed low predictive accuracy overall. For pre-eclampsia the best predictor was inhibin A>2.79MoM positive likelihood ratio 19.52 (8.33,45.79) and negative likelihood ratio 0.30 (0.13,0.68) (single study). For small for gestational age it was AFP>2.0MoM to predict birth weight < 10^th centile with birth < 37 weeks positive likelihood ratio 27.96 (8.02,97.48) and negative likelihood ratio 0.78 (0.55,1.11) (single study). A potential clinical application using aspirin as a treatment is given as an example.

There were methodological and reporting limitations in the included studies thus studies were heterogeneous giving pooled results with wide confidence intervals.

Conclusion

Down's serum screening analytes have low predictive accuracy for pre-eclampsia and small for gestational age. They may be a useful means of risk assessment or of use in prediction when combined with other tests.

Complex congenital malformations and the impact of the plasminogen activator system and beta-hCG in amniotic fluid

OBJECTIVE

The plasminogen activator system and beta-hCG may affect neural crest cells and angiogenesis, and thereby embryogenesis. Therefore, we investigated these parameters in amniotic fluids of pregnancies with a complex congenital malformation.

STUDY DESIGN

In a case-control study amniotic fluid samples were collected from 62 pregnancies with a complex congenital malformation and from 110 healthy control pregnancies at an obstetric department of a large university hospital in the Netherlands. We determined concentrations of tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), plasminogen activator inhibitors (PAI-1, PAI-2), tPA approximately PAI-1 and uPA approximately PAI-1 complexes, and beta-hCG with enzyme-linked immunosorbent assays. Mann-Whitney U-tests and analysis of covariance, adjusting for gestational and maternal age, were performed for data comparisons.

RESULTS

Compared with controls, cases demonstrated significantly lower adjusted geometric mean levels of uPA (24%), tPA (> or =19%) and tPA approximately PAI-1 (35%). Cases showed significantly higher adjusted mean levels of beta-hCG (> or =48%) and PAI-2 (10 ng/mL) than controls. Mean PAI-1 and uPA approximately PAI-1 levels were comparable between both groups.

CONCLUSIONS

Disturbances in the plasminogen activator system and beta-hCG levels are suggested to be involved in the pathogenesis of complex congenital malformations by affecting neural crest cell migration and angiogenesis.