Maternal body mass index and serum concentrations of human chorionic gonadotropin in very early pregnancy

High maternal BMI was associated with low serum hCG concentrations on day 16 after ovulation induction in 2,110 singleton and in 516 multiple pregnancies after ART.

Anne Eskild, M.D., Ph.D., Peter Fedorcsak , M.D., Ph.D., Lars Mørkrid, M.D., Ph.D., Tom Tanbo, M.D., Ph.D.

Volume 98, Issue 4, Pages 905-910, October 2012


To study the association of maternal pre-pregnancy body mass index (BMI) with serum concentrations of hCG in early pregnancy.

Cross-sectional study.

Oslo University Hospital, Norway, 1996-2010.

Among 3,301 pregnancies with live born offspring conceived after assisted reproduction treatment, 2,611 women had information of serum hCG concentrations on day 16 after ovulation induction and pre-pregnancy BMI: 2,110 mothers with singleton and 501 mothers with multiple pregnancy.


Main Outcome Measure:
Human chorionic gonadotropin concentration.

Geometric mean hCG concentration was higher in multiple pregnancies (190 IU/L) than in singleton pregnancies (106 IU/L). In singleton pregnancies geometric mean serum concentration decreased from 117 IU/L in women with BMI <20 kg/m2 to 86 IU/L in women with BMI ≥35 kg/m2. In multiple pregnancies, the corresponding decrease was from 226 IU/L to 130 IU/L. There was a significant negative association of BMI with hCG concentrations log transformed in the study sample as a whole (regression coefficient −0.013), in singleton pregnancies (regression coefficient −0.012), and in multiple pregnancies (regression coefficient −0.03). Conclusion:
Serum hCG concentrations were negatively associated with maternal prepregnancy BMI. One possible explanation may be an effect of adipose tissue-derived signalling molecules on hCG secretion by the implanting embryo.

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