1. Birth Weight by Gestational Age 2. Heavy Metals on Fetal Growth and Neurodevelopment

1. Birth Weight by Gestational Age
Aims:
The study is using registered birth data to establish the model between birth weight and gestational age. Prediction of birth weight at every gestational age, each of which classified into the fifth, tenth, 25th, 50th, 75th, 90th, and 95th percentiles, is made using this model. Thereafter we evaluate the small for gestational age (SGA) in Taiwan with their birth weight at every gestational age.

Research design and methods:
The data set obtained from the birth registries in Ministry of the Internal, was used to predict the percentage of birth weight at every gestational age under the polynomial regression model.

Results:
The average of gestational age is 39 week and the mean birth weight ranges from 3106g to 3150g. We found increasing populations of mothers with foreign nationalities every year, and also slight increase in the percentage of primipara, low birth weight, and preterm labor. Mean birth weight decreased year by year.

For singleton births, birth weight rises with the gestational age up to 42nd week and starts to decrease after the 43rd week. However, for multiple births, birth weight increases following the step up of gestational age.


2. Heavy Metals on Fetal Growth and Neurodevelopment
Aims:
The objective in this study is to estimate the relation between fetal growth and neurodevelopment and low level heavy metal exposure in general population by using umbilical cord blood metal levels.

Research design and methods:
The subjects in this study are chosen pregnant women and their neonates from the participants in the pilot of Taiwan Birth Cohort Study. We used fetal cord blood As, Cd, Hg, Mn, and Pb concentrations to detect the relation between pregnant women blood metal levels and fetal cord blood metal levels. For all neonates, neonatal neurobehavioral performance at two or three days after delivery is detected by neonatal neurobehavioral examination in Chinese Version (NNE-C).

Results:
Relation of fetal growth and neurodevelopment with heavy metal levels were shown in table 4, 5 and 6. As was positive related to tone and motor pattern, and Hg was positive related to head circumference by linear regression models. But for categorical analysis, As and Hg were shown the significant protection for low birth weight. Pb was observed the significant negation for the levels between 11.51 and 21.90 µg/L. But for tone and motor pattern, Cd and Pb were displayed negative for the levels of 0.35 to 0.57 µg/L, and 7.90 to 11.51 µg/L.