Maternal peripheral T helper 1-type and T helper 2-type immunity in women during the first trimester of twin pregnancy

Introduction This study investigated the T helper Th1:Th2 balance in twin pregnancies compared with singleton pregnancies during the first trimester.Methods Blood samples were taken from 24 women with a singleton pregnancy and 14 women with twin pregnancy at 8–9 weeks gestation to examine the ratios of Th1:Th2 and serum human chorionic gonadotropin (hCG) and progesterone levels.Results The average ratio of Th1:Th2 in the twin pregnancies was significantly lower than that in singleton pregnancies (7.3±2.3 vs. 10.5±2.2, p<0.05). There were negative correlations between the Th1:Th2 ratio and serum hCG levels (mIU/ml) (Th1:Th2 ratio = 14.5–4.52×10^–5×hCG, r²=0.41, p<0.05) and between the Th1:Th2 ratio and serum progesterone levels (ng/dl; Th1:Th2 ratio = 23.0–0.63 × progesterone, r²=0.36, p<0.05).Conclusion Our findings show marked predominance of Th2 type cytokines occurring in twin pregnancies is related to the increase in trophoblasts during the first trimester.