Placental gene expression patterns of epidermal growth factor in intrauterine growth restriction

Abstract

Objective: In this study, we compared human placental gene expression patterns of epidermal growth factor (EGF) in pregnancies with intrauterine growth restriction (IUGR) vs. normal pregnancies as control.

Study design: Gene expression of EGF was determined from human placental samples collected from all pregnancies presenting with IUGR at our institution during the study period January 1, 2010-January 1, 2011. Multiple clinical variables were also assessed including maternal age, gestational weight gain, increase of BMI during pregnancy and fetal gender.

Results: A total of 241 samples were obtained (101 in the IUGR pregnancy group, 140 in the normal pregnancy group). EGF was found to be underexpressed in the IUGR group compared to normal pregnancy (Ln2(α): -1.54; p<0.04). Within the IUGR group no fetal gender-dependent difference was seen in EGF gene expression (Ln2(α): 0.44; p<0.06). Similarly, no significant difference in EGF expression was noted in cases with more vs. less severe forms of IUGR (Ln2(α): -0.08; p=0.05). IUGR pregnancies were significantly more common in the maternal age group 35-44 years compared to other age groups. Gestational weight gain and gestational BMI increase were significantly lower in IUGR pregnancies compared to controls.

Conclusions: Placental expression of EGF was found to be reduced in IUGR pregnancies vs. normal pregnancies. This may partly explain the smaller placental size and placental dysfunction commonly seen with IUGR. An increased incidence of IUGR was observed with maternal age exceeding 35 years. The probability of IUGR correlated with lower gestational weight gain and lower BMI increase during pregnancy.

Keywords: AC; BMI; Body mass index; EGF; EGF-receptor; EGFR; Epidermal growth factor; ErbB-1-4; Gene expression; IGF-1; IGF-2; IUGR; Intrauterine growth restriction; LIF; Maternal age; Placenta; TGF-α; TGF-β; VEGF-A; abdominal circumference; body mass index; epidermal growth factor; erythroblastic leukemia viral oncogene homolog 1–4; insulin-like growth factor 1; insulin-like growth factor 2; intrauterine growth restriction; leukemia inhibiting factor; transforming growth factor alfa; transforming growth factor beta; vascular endothelial growth factor A.