MCHB/EPI Miami Conference — December 7 - 9, 2005
Maternal Age: In the Tails of the Distribution
BRASON LEE: I think everybody's received the slide presentation that I gave out. I have to apologize that the abstract that I submitted in the report is kind of an older version of it. The newer version I sent to CDC and if you guys like I can, give me your email address and I'll send you the correct version.
This is again ten-year trends of maternal, advanced maternal age. And the background is that a lot more women over the age of 35 are giving birth, while the numbers of births among teenagers are decreasing and as my presenters here have shown and some of the stuff in the literature that women with advanced maternal age have increased risks of preterm deliveries and other complications. Most of the studies that I looked at, about maybe 15 or so, defined advanced maternal age as 35 and up. Just a couple of them went 45 and up. So, given that most of the births are typically studied in five-year increments up to age 44, they're also known about the trends in 45 and up.
The research method that I used was just a basic descriptive trend of trend over the past ten years of birth statistical files. We looked at resident births, and our population was stratified by those under 45, 44 and under, and 45 and up. And there is 1,2,3,4, 4 questions. Basically, what are trends, what are the social demographic characteristics, the adequacy of prenatal care, and birth outcomes, specifically the low birth weight?
Over all in the state, there's been a decrease of one percent over the past 10 years in births. And as you see in this chart there's a progressive change in each age group. People 24 and under dropped by 13 percent. Twenty-five through 34 there's been relatively no change. Thirty-five to 44 is 27 percent basically. And 45 and up is 75 percent.
Here is the births by pregnant women as percentages of all births, and as you can see, here's the trends. Overall, in the past 10 years the population under 44, 44 and under, 67 percent of the births are from ethnic persons but for 45 and up, 49 percent are from ethnic persons. The largest percentage gain was in 1997-1998 of 4.5 from 46.5 to 51.0 percent.
Here is the relative percent change by ethnicity. As you see, the green colored bars are those 44 and under and the red bars are 45 and up and as you can see here, there's a lot of change. As a percentage African Americans had the largest change, followed by whites, Hispanics, and Asians, but when you look at aggregate numbers, pure numbers, the ranking was: whites, with 481; Hispanics, with 250; Asians, with 170; African Americans, with 45; and American Indians, with one.
Here is a percent of women with advanced maternal age born in the U.S. , statewide 54 percent of everybody born, were U.S. born. And here, in earlier years it was 46 percent, 47 percent, and over the past 5 years it's gone up to over 55 percent. Here are the women with college education. Overall, statewide it was about 24 percent. Here, with the 44 and under group, it's about in the area of 24, 25 percent. But among the 45 and ups, it was a higher rate, from 33 to 48 percent. There's a 17.1 percent change overall for 45 and up during this time period.
Here is the first time births among women with advanced maternal age. And it's ranged from 22 percent to 30 percent. Statewide it was about 38 percent. The largest percentage gain, again, occurred in '96-'97 of 2.7 percentage points and again from 2003-2004 with 2.3 percent. Here I have women with proper prenatal care and again, overall the women with proper prenatal care was 47 percent, but for the 45 and up group it was 78 percent in the past year, 18 percentage point change from '95 to 2004 and you can see where the people under 44 fall.
Okay, this is the adequate prenatal care. Overall, the percent of women who had adequate prenatal care was 78 percent. And here there was some fluctuations among the 45 and up group, but they're overall higher than the people under 44.
This slide here is women with multiple births by age. And overall, the 45 and up had a much higher rate of multiple births. One out of 8 women had multiple births, whereas for the 44 and under it was one out of 75.
This is the percentage of low birth weight infants. And the unit of analysis here changed differently from other units of analysis. The unit analysis here are babies rather than pregnant women. And overall, for the 45 and up group, one out of seven babies were low birth weights versus in the 44 and under it was one out of 17. This is for the overall, but when we controlled for just singleton births the percentage of low birth weight was still higher among the 45 and up. Overall, it was 8.9 percent. One out of 11 women had low birth weight infants, whereas the 44 and under group was one out of 20.
That brings me to my conclusion. As the other speakers will talk about here is that they basically will need a more enhanced surveillance of advanced maternal age. Particularly when the rate of prenatal care is up, but also low birth weight. There's going to be a need to enhance the targeting and outreach of low birth weights. There's some issues that will need looked into is since there's a trend of women going to school and focusing more on career first before childbearing. And then recognize the issues of service delivery, such as health literacy and access. When I talk about health literacy I'm talking about the ability to understand, read, and act on health information.
And the last issue is the implications for broader public health concerns and proper policy concerns, such as family care giving. I think that I'm done. Completed. Any quick questions?