Prevalence of birth defects and rubella infection in pregnant women in Gansu, west China. A survey.

OBJECTIVE

To determine the incidence, disease types, sequence of birth defects and prevalence of IgG and IgM in rubella infection in prepregnancy and pregnancy within 3 months in Gansu, People's Republic of China, and to determine a baseline of birth defects for an intervention project on birth defects in Gansu.

STUDY

DESIGN

Liveborn and stillborn infants from January 1, 2001, to January 1, 2002, and 518 prepregnant and 373 pregnant women in 3 months in 4 counties, including 42 communities selected random by stratification cluster sampling for a survey on the economic and geographic features in the province in October 2001 were investigated. Every infant born in the study period was surveyed. The types of birth defects were classed by standard diagnostic codes (ICD-9). Five-milliliter blood samples were obtained from every prepregnant and pregnant women. Rubella IgG and IgM were measured by enzyme-linked immunosorbent assay.

RESULTS

The overall number of birth defects in Gansu was 102 (16.35%). The incidence of birth defects by sex was 62 males (18.55%) and 40 females (13.9%). The types of birth defects were neural tube defect, 44 cases (7.07%); limb defects, 13 (2.09%); cleft lip and palate, 5 (0.8%); and Down syndrome, 3 (0.48%). Low birth weight occurred in 31 cases (4.98%). The seasonal incidence birth defects was spring, 24 cases (23.52%); summer, 31 (30.39%); autumn, 26 (25.49%); and winter, 21 (20.59%). There were significant differences between 4 counties. The death rate from birth defects was 48 cases (47.06%). The positive rates of IgM and IgG of rubella infection of prepregnant women were, respectively, 5.02% and 83.78%; in pregnant women they were, respectively, 2.41% and 86.33%. The seropositive rate of rubella infection of prepregnancy was 88.80%; that of pregnancy was 88.74%.

CONCLUSION

The rate of rubella infection in prepregnant and pregnant women within 3 months in Gansu was one of the highest in the People's Republic of China. The rate of birth defects in Gansu was one of much higher than in the People's Republic of China as a whole.