LAUSR

Abstract The present study aimed to analyze the positive rate of Down syndrome in second-trimester pregnant women in 1 lunar cycle and calculate variation coefficients of daily person numbers and daily positive rates in this population so as to explore the relationship of the lunar cycle with Down syndrome screening and its effects. Data and laboratory results of 51,450 second-trimester pregnant women who underwent Down syndrome screening between May 2013 and June 2017 of the Chinese lunar calendar were collected. The patients were allocated into groups according to the time period of the lunar cycle based on the start date of their last menstruation. In the Chinese lunar calendar, 1 lunar cycle is divided into eight time periods. The positive rate of Down syndrome in pregnant women with the same start date of last menstruation and changes in their variation coefficients of daily person numbers and daily positive rates were analyzed. The findings displayed the lowest positive rate of Down syndrome in the group of pregnant women who had the start date of last menstruation within the full-moon time period. The greatest variation coefficients of daily person numbers and daily positive rates were also found in the same group. The study showed that the moon indeed affected pregnant women, and the effect reached the peak by the full moon. The effect interfered with the body homeostasis of pregnant women to a certain degree. Therefore, the relationship of the lunar cycle with Down syndrome screening reflected the interaction of the moon with the homeostasis of pregnant women.