It was obviously that the average maternal age of the pregnant in 2020 is more advanced compare with 2019,even merely about one year gap. This result confirmed the global trend of postponement of child birth, both in developing and developed countries. An increasing number of well-educated women whom stepping into the workforce, with better and higher education, work and socioeconomic pressure, attitude to marriage and fertility make their maternal age been prolonged continually. The average age of primipara was 21 years in 1972 and in 2016 it reached 26.3 years[8].Advanced maternal age is usually defined as being 35years, which is believed to relate to varying complication and adverse outcomes[9].In our study, maternal age of two group women was less than 35 and little different existed in absolute value. Therefore, the impact of age can be ignored from the discussion of the result.