Oral health care in the second trimester (7-10 months): (1) pay attention to nutritional balance: as the fetus continues to grow, increasing the burden on the mother, at this time should pay attention to a balanced diet and appropriate activities to prevent pregnancy hypertension, heart disease, nephritis, anemia, etc.. (2) conservative treatment of dental disease: if oral diseases are found at this time, conservative treatment such as temporary treatment, do not accept tooth extraction and other traumatic treatment, so as not to cause premature birth; (3) strengthen the learning of oral health care knowledge: because the mother may have temporarily not in the heavy (3) strengthen the learning of oral health care knowledge: because the mother-to-be may be temporarily not in the heavy work position, this is a good time for pregnant women to learn the oral health knowledge of the newborn.