Objective: To report the results of prenatal triple marker screening on a population of Japanese pregnant women.
Methods: From April 1994 through March 1999, a total of 32,925 native Japanese women with singleton pregnancies requested a triple marker-screening test. Multiples of the median values for 3 markers and individual risks for each patient were calculated following adjustment for the Japanese weight correction factor. The risk cut-off values used for Down syndrome (T21), open spina bifida (OSB) and trisomy 18 (T18) were 1: 295, 1: 290, and 1: 100, respectively. Follow-up information was collected postpartum and statistically analyzed.
Results: Detection rates (DR) of T21 for women less than 35 years, over 35 years and overall were 58, 94, and 83%, respectively. DR of T18 for women less than 35 years, over 35 years and overall were 75, 79, and 79%, respectively. DR of open neural tube defects (ONTD) was 100%.
Conclusions: The first cumulative data of an intervention program and prospective follow-up studies in Japan have proven to be similar to other published reports. Individual risk values were calculated for each pregnancy for T21, T18 and ONTD. This screening program is more effective than age-dependent screening for detecting T21, T18 and ONTD pregnancies.