title: Elevated second-trimester free beta-hCG as an isolated finding and pregnancy outcomes.
abstract: OBJECTIVE
  To investigate the relationship between unexplained elevated second-trimester free beta-human chorionic gonadotropin (beta-hCG) levels and pregnancy complications as well as adverse pregnancy outcomes.
  
  
  METHODS
  The study cohort comprised 2,110 non-smoking women with chromosomal and structurally normal fetuses at low-risk for both Down's syndrome (risk <1:250) and neural tube defects (maternal serum alpha-fetoprotein <2.0 MoM). A free beta-hCG value of > or =2.0 MoM was used to define the populations with elevated levels of free beta-hCG. Descriptive statistics, chi2 test, Fisher's exact test, and logistic regression analysis were used for statistical analysis, and p < 0.05 was considered statistically significant.
  
  
  RESULTS
  The mean maternal age of the study group was significantly lower than in controls (27.9 +/- 4.3 and 30.6 +/- 5.1 years, respectively, p < 0.05), while the proportion of primigravidas was significantly higher compared to that of controls (p < 0.05). After adjustment of the 2 groups according to maternal age and parity, we observed an increased incidence of preeclampsia among women with elevated free beta-hCG levels in relation to controls (p < 0.05). However, a logistic regression analysis demonstrated that the free beta-hCG level was not a predictor of the occurrence of preeclampsia. No significant relationship was found with the incidence of gestational diabetes, oligohydramnios, polyhydramnios, pregnancy-related hypertension, intrauterine growth retardation, preterm delivery, spontaneous abortion and stillbirths (p > 0.05).
authors.affiliation: Department of Biology, School of Medicine, University of Rijeka, Rijeka, Croatia. bojana@mamed.medri.hr
authors.forename: Bojana
authors.initials: B
authors.lastname: Brajenović-Milić
authors.forename: Dubravka
authors.initials: D
authors.lastname: Tislarić
authors.forename: Marta
authors.initials: M
authors.lastname: Zuvić-Butorac
authors.forename: Josip
authors.initials: J
authors.lastname: Bacić
authors.forename: Oleg
authors.initials: O
authors.lastname: Petrović
authors.forename: Smiljana
authors.initials: S
authors.lastname: Ristić
authors.forename: Marko
authors.initials: M
authors.lastname: Mimica
authors.forename: Miljenko
authors.initials: M
authors.lastname: Kapović
mesh_terms: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood* / Q000453:epidemiology*; D011256:Pregnancy Outcome; D011262:Pregnancy Trimester, Second; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human