• Way too many infants die in this country – ctd.

    A reader fisked the concluding statement in my previous post by email:

    Although your post about infant mortality is spot on, there really isn’t much evidence that prenatal care has a major impact on preterm delivery, especially in black women.  The only intervention that I’m aware of for which there’s RCT data is the use of progesterone in women with a history of prior preterm labor, and even that is a bit shaky (I’m actually working on a CEA of that right now, and when you drill down on the published data it’s not nearly as convincing). Prenatal care is undoubtedly a good thing, and there is evidence that it does improve some outcomes (although, especially in the US, we do too much of it), but, sadly, the one thing it doesn’t seem to do is prevent preterm delivery.

    To which I replied: “Fair enough.  You bring up good points, and I’m sure I let my emotions get the better of me there. But there has to be a reason for the preterm labor. Do you think it’s genetic? Or is it lifestyle choices – which I’d argue could be impacted and reduced by better care. No?”

    His answer was very complete and chock full of evidence, so I’m posting it in its entirety (with his permission):

    Personally, I think there is some genetic component–at every gestational age, black babies are smaller than babies of other ethnicities (the distribution is still normal, but it’s shifted to lower weights–that’s why any discussion of racial disparities in low birthweight needs to adjust for this), but, at any gestational age, their survival is better (a black baby born at 31 weeks has better survival than a white baby, but, because there are more 31 week deliveries, overall mortality is higher in blacks), and there are differences in the distribution of pelvic shapes (black women are more likely to have a narrower pelvic outlet.    There’s been a lot of speculation about differences in responses to infection/inflammation, uterine physiology (black women are much more likely to get fibroids, for example), or generalized vascular reactivity.    From an evolutionary perspective, there may have been some advantage to having smaller babies at earlier gestational ages.    But I’m not aware of a lot of active research into this.

    The disparity exists even when you control for other factors–for example, there’ve been a series of studies in active duty military women, who all have access to the same care, have similar incomes, etc, and the disparity is still there (e.g., http://www.ncbi.nlm.nih.gov/pubmed/16477258).     There’s a lot of interest in looking at disparities in environmental exposures (http://www.ncbi.nlm.nih.gov/pubmed/18828412) and some discussion about the effects of racism/social deprivation on stress (although I’m somewhat skeptical about that).   Black women tend to have shorter interpregnancy intervals, which are associated with preterm birth, but I’m not sure that’s causative.     But all of these things are bigger social/public health issues and, by the time someone’s in prenatal care, it’s probably too late.    Sure, smoking cessation probably helps (although, again, very little direct evidence of an effect on birth outcomes–we did an RCT of NRT here and found no difference in birth outcomes despite higher quit rates), but that doesn’t explain very much of the black/white disparity.

    Here’s the Cochrane review on increased support for women at high risk for preterm birth: http://www.ncbi.nlm.nih.gov/pubmed/20556746  and here’s the one for number of prenatal visits http://www.ncbi.nlm.nih.gov/pubmed/20927721 (there is an impact on perinatal mortality, but it’s in settings with an already low number of visits, where perinatal mortality is common, and where the causes of perinatal mortality are less likely to be prematurity).

    I admit it’s hugely frustrating, because that excess infant mortality is by far the biggest driver of disparities in life expectancy.   Some of the other causes are potentially impacted by lifestyle choices that could be impacted by care and/or other strategies (for example, there’s a big difference in MVA-attributable infant mortality between blacks and whites, which is probably due to differences in car seat/seat belt use, and we have some preliminary data… which suggests that MVA-attributable stillbirth is more common in blacks, again because of less frequent seat belt use.    We can address that, but it’s not nearly as big a contributor as prematurity).   But it seems likely that a lot of it is due to some combination of genes and environment that can’t be easily dealt with at the health care “system” level, and until we find a better primary prevention strategy, we’re stuck with few options besides short term tocolysis and antepartum corticosteroids.

    None of this lessens the fact that infant mortality in the US is still too high, compared to other countries. But my final assertion that better access to good prenatal care would solve this problem seems like an unsubstantiated claim. I still think it does a lot of good for many things, but this reader may be right that it won’t do much to prevent the deaths due to prematurity.

    P.S. This reader’s comment and follow-up is a phenomenal example of how you should go about getting us to pay attention and change our minds.

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    • FWIW, and it’s not worth much since we didn’t have any kids, so I haven’t watched the process in detail, my _impression_ is that Japan is incredibly proactive about prenatal care, and has been since before I got interested (I’ve been here since ’86, after a year in ’79). At least in the schlock dramas on the TV, pregnant women are given and taught how to keep a detailed diary of the pregnancy, with lots of check ups throughout. Given the rather good performance in this aspect over here, I’d say that overdone prenatal care has to be at least part of it. But obesity and smoking are rather less prevalant amongst pregnant women here than in the states.

    • Thank you for this. I read the original post and this follow up in their entirety. I felt like I learned something from the first post and now I know that I learned even more from this one.

      Even though I’m not in the healthcare field and a lot of this went way over my head, I appreciate the fact that you and the commenter were willing to publish all of this. It’s nice to see people disagree civilly and use facts to back up their arguments.

      The biggest reason I read this blog is to find facts presented in a neutral way and you have succeeded yet again. Good job to both of you.

    • Interesting.

      The key question is whether this is indeed genetic or whether it is due to both acute and cumulative multi-generational socio-economic victimization of African Americans. I would be far less quick to dismiss that as a hypothesis than your correspondent, since that seems to influence so many other outcomes, from school to prisons.

      Three important questions suggest themselves immediately:

      First, do the African American tendencies toward low birthweight and toward prematurity hold true regardless of socio-economic class? This should be easy to test by looking at data for African Americans in higher socio-economic situations, of whom there are now enough to examine.

      Second, how do Afro-Britains, Afro-French, Afro-Canadians, and so on compare in this data? In other words, is the situation in America mostly due to America or mostly due to genetic pools? There are large African populations in several other countries, and examination of their data would be useful.

      The data from the military does not answer these questions, since the root socio-economic class of African American enlistees tends to favor lower income and class, and many of the potential impacts would extend to them as well.

      In another vein, reading the Cochrane data, it seems that the first article does not address the same question (availability or lack thereof of ANY prenatal care,) but rather looks at the use of non-physician caregivers in programs to support the mother beyond ordinary prenatal care, a completely different issue. The second article actually strongly suggests that there IS an impact of prenatal care on prematurity and birthweight, and the conclusion points that out.

      The crucial point is that in the US we are not dealing with the question of numbers of prenatal visits, visits by social workers, and so on. Rather in our system we are dealing with the question of zero prenatal care versus prenatal care. As anyone who has worked in an inner city hospital knows, the situation of women being admitted in labor with no prenatal care at all is, unfortunately, very very common.

    • 1. Are you aware of the fact that the definition of what constitutes a live birth varies significantly from one country to the next – and sometimes even with the same country?

      International:
      http://www.ncbi.nlm.nih.gov/pubmed/11862950
      Intranational:
      http://www.ncbi.nlm.nih.gov/pmc/articles/PMC554850/

      Plenty more where that came from.

      2. How confident are you that you can objectively determine what affect the variations in determining what constitutes a “live birth” on the magnitude of infant mortality in the US vs other developed countries?

      3. If the answer to 2 is “less than 100%,” does that affect your thinking about the relative quality of pre and post natal care in the US, and the policy changes that you would like to see implemented to address it in any way?

    • Add to the racial differences the fact that fertility treatments are more common in the USA which produces more multiple births and lower birth weight and higher infant mortality.

      BTW I would be OK with banning fertility treatments except that I think that the ban would do more harm than good pushing desperate people to go outside the USA for the treatments.

    • This also illustrates why international comparisons are meaningless unless they factor out differences in racial diversity

    • Let me recommend this 2011 review article on the effectiveness of antenatal (pre-natal) care in reducing infant mortality and pre-term births.

      http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3050773/

      Title: The effectiveness of antenatal care programmes to reduce infant mortality and preterm birth in socially disadvantaged and vulnerable women in high-income countries: a systematic review

      BMC Pregnancy Childbirth. 2011; 11: 13.

      Published online 2011 February 11. doi: 10.1186/1471-2393-11-13
      PMCID: PMC3050773
      Copyright©2011 Hollowell et al; licensee BioMed Central Ltd.

      Background

      Infant mortality has shown a steady decline in recent years but a marked socioeconomic gradient persists. Antenatal care is generally thought to be an effective method of improving pregnancy outcomes, but the effectiveness of specific antenatal care programmes as a means of reducing infant mortality in socioeconomically disadvantaged and vulnerable groups of women has not been rigorously evaluated.

      Methods
      We conducted a systematic review, focusing on evidence from high income countries, to evaluate the effectiveness of alternative models of organising or delivering antenatal care to disadvantaged and vulnerable groups of women vs. standard antenatal care. We searched Medline, Embase, Cinahl, PsychINFO, HMIC, CENTRAL, DARE, MIDIRS and a number of online resources to identify relevant randomised and observational studies. We assessed effects on infant mortality and its major medical causes (preterm birth, congenital anomalies and sudden infant death syndrome (SIDS))

      Results
      We identified 36 distinct eligible studies covering a wide range of interventions, including group antenatal care, clinic-based augmented care, teenage clinics, prenatal substance abuse programmes, home visiting programmes, maternal care coordination and nutritional programmes. Fifteen studies had adequate internal validity: of these, only one was considered to demonstrate a beneficial effect on an outcome of interest. Six interventions were considered ‘promising’.

      Conclusions
      There was insufficient evidence of adequate quality to recommend routine implementation of any of the programmes as a means of reducing infant mortality in disadvantaged/vulnerable women. Several interventions merit further more rigorous evaluation.

    • I suppose I feel the familiar frustration when data doesn’t support preconceived notions. Still, I read that infant mortality in Singapore is 2.31, Bermuda 2.46, Sweden 2.75, the US 6.6, Alabama 9.5 and non-white in Alabama 13.4, with huge disparities between counties in the state,

      Somehow it just ‘feels’ as if there’s bound to be some intervention more effective than tocolysis or antepartum corticosteroids to influence the disparities.

    • This is late in this thread, but I have found a study that addresses some of the issues we have been discussing.

      An Oxford study of infant mortality data in the UK has been published in three parts. The third paper is the one of most interest in this thread topic, although all three are worth reading.

      The link to the third paper, which addresses the question of ethnicity and infant mortality in the UK:
      https://www.npeu.ox.ac.uk/files/downloads/infant-mortality/Infant-Mortality-Briefing-Paper-3.pdf

      Two very interesting facts leading to important insights emerge immediately.

      The first is that the African Americans suffer from a one third worse rate of infant mortality than the worst performing groups in the UK, Afro-Caribbeans and Pakistani’s (!!). This does not prove but strongly suggests that whatever problems affect African Americans in this is environmental and specific to the US, not genetic, since Afro-Caribbeans share an identical ethnic background with African Americans.

      Second, and perhaps more interesting, is the fact that people of direct African descent have a significantly lower rate of infant mortality than Afro-Caribbeans in the UK. Since most African Britains share the same West African ethnicity as most Afro-Caribbeans, this strongly suggests that the difference is not genetics but rather having suffered through the mill of captivity and slavery followed by ongoing tens of decades of discrimination, poverty, and the associated problems.

      Although I believe that more study of this question would be useful, I think the notion that the poor performance of the US in infant mortality can be excused by racial genetics is disproved by this study, and that the remaining supposition would be that the problem is caused by the poor performance of the US health care system, the massive failure of the US to deal fairly with African Americans, or a combination of the two. The fact that Pakistani’s are the other severely impacted group in the UK strongly argues that the second explanation is likely very important, while the difference between Afro-Caribbeans in the UK and African Americans in the US suggests that flaws in our health care system are also important.

      For anyone interested, here are links to the first two papers as well:
      https://www.npeu.ox.ac.uk/files/downloads/infant-mortality/Infant-Mortality-Briefing-Paper-1.pdf
      https://www.npeu.ox.ac.uk/files/downloads/infant-mortality/Infant-Mortality-Briefing-Paper-2.pdf

    • It’s hard to reconcile the conclusions of this post with articles like this:
      http://www.jsonline.com/news/opinion/team-effort-131642548.html