Serum C-reactive protein levels are associated with clinical pregnancy rate after in vitro fertilization among normal-weight women

OBJECTIVE: To assess whether low-grade inflammation, measured by serum high-sensitivity C-reactive protein (hsCRP) levels, is associated with in vitro fertilization (IVF) outcomes. DESIGN: A retrospective study. SETTING: University-affiliated IVF center. PATIENT(S): In the present study, 875 women of normal weight who underwent their first fresh embryo transfer (ET) cycles for IVF treatment were divided into three groups according to serum concentrations of hsCRP. INTERVENTION(S): Serum from women undergoing IVF was collected on days 2-4 of a spontaneous menstrual cycle prior to the commencement of ovarian stimulation. MAIN OUTCOME MEASURE(S): The IVF outcomes included implantation, biochemical pregnancy, clinical pregnancy, miscarriage and live birth rates. RESULT(S): The women were divided into three groups according to the baseline serum levels of hsCRP as follows: low hsCRP (<1 mg/L; n=517), medium hsCRP (1-3 mg/L; n= 270), high hsCRP (>3 mg/L; n=88). The maternal age was similar among the three groups. The women in the high and medium hsCRP group had significantly higher BMI compared with those in the low hsCRP group. The protocol of controlled ovarian hyperstimulation, the gonadotropin dose administered, the serum estradiol levels, progesterone levels and the endometrial thickness on the day of triggering, as well as the number of retrieved oocytes, fertilized oocytes and good quality embryos, and the oocyte maturation rate were similar among the three groups. Implantation, biochemical pregnancy and clinical miscarriage rates did not differ significantly were not significantly different among three groups. The clinical pregnancy rate was significantly lower in the high hsCRP group compared with that in the low hsCRP group (50.0% versus 63.4%; P<0.0167), which contributed to a significant decrease in birth rate (39.8% versus 53.8%; P<0.0167). High serum hsCRP levels was found to be a factor affecting live birth rate CONCLUSION(S): Among women of normal weight undergoing their first IVF treatment, it was found that low-grade inflammation was associated with reduced clinical pregnancy and live birth rates following fresh ET cycles.