**3. Results**

#### **3.1. Characteristics of the research population and body weight of fetus**

Five pregnant women who were experiencing sPTL-IM were recruited in the study group while 10 pregnant women experiencing sTL-IM were recruited as the control group. Clinical data of these pregnant women were compared between both groups. As shown in **Table 1**, there were no statistical significant differences between sPTL-IM and sTL-IM groups in maternal age and parity. Pregnant women resulted in a PTB due to sPTL-IM have significantly lighter babies (at birth) and placentas than their control (*P* < 0.05, **Table 1**).
