AMCHP 2005 ANNUAL CONFERENCE
DELIVERING RESULTS, IMPROVING PREGNANCY & BIRTH
February 19-23, 2005
NAN STREETER: Good morning. How’s everybody this morning? You’re not? So you’re not going to tell me how you are. Well, it’s my pleasure to talk about work that Lois and I have worked on together around pre-maturity and I think Dr. Lu and Dr. Collins certainly set the stage very well for issues related to pre-maturity and, you know, issues that are not easy to resolve. So we do definitely have our work cut out for us. Well, I wand to tell you a little bit about preterm in Utah and how we use PRAMS data to study mothers who give birth to preterm infants. Jo Ann had already mentioned the definition and everybody knows that. In Utah the preterm birthrate is 9.5 percent. These are 2003 data. The interesting part of this is that while Utah ’s preterm birthrate is lower than the national rate, our increase since 1992 is 40 percent compared the national increase of 13 percent. So we are very concerned about preterm in Utah and why our rates are increasing more than the national rates.
This graph here shows you how Utah fairs compared to the nation, over time, and just a couple of comments about sequela of pre-maturity. We all know that it’s the leading cause of perinatal in otherwise normal newborns. In Utah about 80 percent of infants who died during the neonatal period, so the first seven days of life, were born prematurely in 2002. Some other things to consider about pre-maturity, mortality certainly is a concern. But in addition to that, for survivors of pre-maturity, we are concerned about the long-term outcomes. Fifty percent of infants that were born at extreme pre-maturity have disabilities as demonstrated at 30 months of corrected age. These include mental and psychomotor development disabilities, neuromotor function or sensory function disorders, and communication function disorders.
We are fortunate in Utah to have a neonatal follow up program that is administered or managed by the department and so we have some very rich data from that particular program. And so the data at the beginning of this presentation will talk a little bit about the data from the newborn follow up program and then I will be talking more about the PRAMS data and the study that we did related to preterm birth. So during this period of time from 1986 to 2000 there were almost 550 babies that were born at less then 27 weeks gestation. The average birth weight was 728 grams, the range was 436 to 1500. And the gestational ages of these babies range from 21 to 26 weeks and you can see the distribution that obviously the majority of those babies were in the later gestational age group. The average hospital stay for these babies, 107 days, 3 months.
The range was 41 to 278 days. Fifty percent of these babies experienced some form or some degree Intraventricular Hemorrhage and 20 percent of these had grade three or four Intraventricular Hemorrhage. In terms of retinopathy of pre-maturity, 80 percent had some stage of ROP and 34 percent had stage three or greater. Cerebral Palsy about 18 percent of the survivors experience Cerebral Palsy and 38 percent of these babies went home on oxygen. So let me tell you about the study that we conducted in Utah . This was a collaborative effort with Utah Department of Health Staff and Lois was the lead on this effort in the Department. And we collaborated with the University of Utah Health Sciences Center with the OB Department. We have a very strong relationship with these folks and we really enjoy that relationship because it is mutually beneficial, fortunately. So the study question was, what are the significant factors that are associated with preterm births in Utah . And again, we’re not talking about cause and effect. I think many times we can’t determine the cause.
Sometimes we can certainly look at this and say, well yeah, you would expect that a baby would be born pre-maturely, but as we know, more often than not, we can’t. So the methodology of this particular study involved linking the PRAMS dataset and birth certificate data set for the period of time of 1999 to 2001. And we did exclude multiple gestation pregnancies from this study because one would assume that women who have, who are carrying more than one fetus, would deliver preterm. The dataset was divided into two mutually exclusive categories and I’ll talk about that in a minute and chi-square tests were conducted to identify significant variables associated with the two groups. Thank you. All right. So the two groups, we have the indicator preterm births, so the births that we would look at and say yes, we could understand why those babies were born preterm. And then the spontaneous preterm births, those that we can’t identify a obvious variable or factor that would have resulted in a preterm birth.
So for, in terms of definitions, the indicated preterm births were those that were associated with pregnancy complications or conditions that required obstetric intervention for early delivery, or led to preterm labor resulting in preterm birth. And then the spontaneous preterm births were those in which as I mentioned earlier, that the underlying cause for the preterm birth was not evident. So as we analyze the data, what we discovered was that there were differences between the two groups as you might expect. So the factors that we used to determine the category of preterm births that fit in the indicated are here and so you know, as you can imagine that if you have a mom that has a maternal condition, a chronic disease, that that mother might be expected to deliver preterm as well as complications et cetera. So all women who were, fell into these categories as evidenced by birth certificate data were put into the indicated preterm birth category. And then the spontaneous births were all the women who didn’t in to the indicated preterm birth categories.
Now as we analyze the data, as I said, we identified significant factors that were associated with both groups of women. And the indicator preterm births account for a little over half of preterm births in Utah , with a mean gestational age of 33.8 weeks. And the spontaneous preterm births account for 47 percent of these births with a mean gestational age of 34.5 weeks. So a little bit older and a little bit fewer. So, in terms of significant factors associated with indicated preterm delivery, primarily a mom having a history or a preterm birth. And I think Dr. Lu, you know, spoke to that very nicely in terms of inner generational history and the importance of that. Women who were other than white, women who smoked during the last trimester of their pregnancies, women who were age 20 to age 24 years, and women who had less than a high school education, and women who were low income.
So, the next few graphs illustrate for you, what the differences were than between the women who delivered preterm and were in the indicated category by the variables that we talked about. And so for the women who had a history of preterm birth, you can see you’re talking about, you know, a significantly greater risk of having a subsequent preterm birth among women who have had a history. And then in terms of smoking, again, a significant difference between women who smoked and women who did not smoke. Terms of race, again, not surprising that women who were other than white race have a significantly higher risk of a preterm birth, among the indicated. And then this illustrates the age and again a significant difference among women between the age of 20 to 24. In looking at maternal education, less educated women have a much higher risk of preterm birth in the indicated category and then also same with income. So then we looked at the spontaneous group.
And the factors that we identified among this group again, the history. Women who use fertility drugs to conceive the pregnancy were significantly at greater risk for a spontaneous preterm delivery. Women who had some college education and I think you can kind of see a link here that one might assume that if you are more educated, you have a higher income, you have greater access to fertility treatment so there may be an association there. Women who had pre pregnancy BMI, body mass index, categorized as either or under or overweight. All right, so here are some graphs again to illustrate the differences among the women who had spontaneous preterm deliveries, by previous preterm birth and again significant difference, you know, five fold difference. Looking at fertility drug use, you have more than a two fold difference among women who used fertility drugs to get pregnant. Education. And this finding actually is kind of interesting in that you have a high rate among women who had some college education but also if you looked at less than high school, kind of an interesting finding.
And then women who as I mentioned before were underweight or overweight had a much higher risk of having a spontaneous preterm delivery compared to the other categories, and interestingly enough, not the obese. So some summary of our finding, indicated births were slightly higher and perhaps some of this is due to and I think this is probably not just a reflection of Utah’s situation but also national situation is that we have many great technologies that have permitted delivery to protect the mother’s health, to protect the infant’s health by delivering preterm so that the fetus is not kept in utero and exposed to more risk as well as the mother. Pre-conceptional health issues such as chronic disease, poverty, tobacco use. We know that many of these are linked to indicated or you would expect to see more preterm birth among this group. And then iatrogenic contribution, inductions, for example, where a woman may ask her provider to, I’m tired of pregnancy, I’d like to deliver before my due date.
And perhaps the dates aren’t exactly accurate and so you may have an iatrogenic contribution to preterm birth. The spontaneous births as I mentioned, you know, accounted for almost half, but we can’t identify any potential risk factor at this point with the data. But again to remind you that preterm birth was five times greater among women who had a previous history. Again, that kind of reproductive programming that Dr. Lu had talked about. Demographic characteristics that resemble the general population, so that these women looked like just the general population of Utah moms. And the contribution of pre pregnancy weight and fertility drug use seemed to be contributing or at least associated. So, obviously as I mentioned before, preterm birth whether it was spontaneous or indicated is higher among women who have a previous history.
Some of the limitations of the study, we did use birth certificate data and we do know that with birth certificate data there may be some under reporting or inaccurate reporting of medical risk factors. Also, PRAMS data are self-reported and so there may be some recall bias. And the methodology did not separate the pri mips from the mul tips. And so one of the things that we want to do when we go back home is to separate out the pri mips from the mul tips to determine whether there are other variables that, you know, separate these two groups of women other than the previous preterm history. So the conclusion, the strongest risk factor was previous preterm birth and obviously screening and education of providers as well as women of childbearing age is really critical, in terms of understanding the relationship of pregnancy history.
And improved pre-conceptional counseling and care as Jo Ann mentioned, you know, you have providers who are not asking women about alcohol and tobacco use, et cetera that we need to educate providers about counseling women about the importance of, you know, adequate BMI’s and chronic disease management and smoking cessation before pregnancy. And then the need for continued research. There are some studies that are indicating a linkage between periodontal disease and preterm birth, using prophylactic progesterone in women with previous history or preterm birth and so obviously there’s need for a lot of continued research. As I mentioned we want to look at comparing pri mips with mul tips to address the issue of the previous preterm birth history and separating out the moms who have pre-mature rupture of membranes to see if there is some associated factors with those women compared to the other groups, and do some further logistic regression studies to look at the interactions between the variables.
So what can we take home? Well, obviously, data on birth certificates being accurate is critical for all of us to being doing studies and conducting studies particularly related to reporting medical risk factors. The maternal birthing history is extremely important for determining the potential for repeating that birth history, whether it’s preterm birth or C-section or whatever. You know, the presentations this morning were I think enlightening in terms of, you know, if a mother herself was born low birth weight, the chances of here delivering a low birth weigh infant are significantly increased. And we see that also in terms of C-sections et cetera. So we really need to be looking at the mother’s, mother’s history. And obviously preterm birth is a multi factorial complex problem that we need to continue to study and investigate and try to improve as we work on these issues. Here’s my contact information. You have it on the handout and thank you very much.