Regarding to the control group with sham acupuncture, after the umbilical cord is clamped, the acupuncturist disinfects the abdominal area with antiseptic and pricks the needle in the placebo point with a sterilized 0.25x40 mm steel needle. The control point is located at the same horizontal level than the Ren Mai 6 point, but at 0.6d to the left of the anterior midline of the mother. In this case, the sterilized steel needle of 0.25x25 mm will be inserted 15 mm into the tissue.