Frequency of prenatal care visits and infant birth outcome: Experience from Taiwan

Objective: To evaluate frequency of prenatal visits on infant birth outcome.

Method: We linked the data from Taiwan's birth registry and health insurance claims and adopted the propensity score matching (PSM) to select a subset of pregnant women who had similar pretreatment characteristics; however, they differed in the number of prenatal visits. A total of 907,054 women with singleton pregnancy were selected. We classified women into five groups: receiving no care/unknown, 1-3 visit, 4-6 visit, 7-9 visit and ³ 10 visits. Measure of Infant birth outcomes included low birth weight (<2500g), APGAR score at 1 and 5 min (<7) as well as the birth's defect. The 1:1 case-control match on the propensity score was performed to select the best match. Results: There was a significant difference among women receiving different numbers of prenatal visit. Those who received ³ 10 visits had the lowest rate of majority of infant birth outcomes compared to these in the other groups: reducing low birth weight from 1.22% to 2.57%, APGAR score at 1 min from 0.08% to 0.60% and at 5 min from 0.00% to 0.18%. Except for those who received no care/unknown, those who received ³ 10 visits also had lowest rate of birth's defect from 0.08% to 0.19%.

Discuss: This study used PSM to estimate the benefit of prenatal visits on infant birth outcomes to diminish the selection bias. A limitation to this method was that we could not compare the results of pregnant women who were not selected through PSM process.