A staggering 95 percent of couples have stopped having premarital health checks since the procedure was made voluntary last October, according to local health authorities.
Only 3 percent of couples now receive premarital checks, which are not mandatory for marriage registration, and medical experts are worried about an increase in baby deficiencies.
Experts believe most of the 3,000 known inherited diseases can be prevented through premarital and prenatal checks.
In an attempt to uncover the reasons for the sharp decrease, local health authorities will survey 1,980 couples in Hongkou District and Chongming County to find out what newlyweds understand about the checks, as well as their wider understanding of contraception and childbearing.
"The results of the survey will allow us to prepare better services and methods to attract more couples in the future," said Fan Lingjun, director of Hongkou District Population and Family Planning Commission.
The surveyed couples will be divided into three groups. Final results from the survey will be known by the end of next year.
Officials said the cost for the premarital check is 68 yuan (US$8.19) per person but the government is considering providing it for free.
Health experts stress the premarital check is essential to detect diseases early and ensure the health of the couple and future children.
"Since the city introduced premarital check in 1988, doctors have provided guidance to some 1,000 couples who have been required to delay marriage or not deliver children," said Li Shanguo, an official from the Shanghai Health Bureau.