September is National Infant Mortality Awareness Month

Infant mortality is how many live-born children die within 365 days of their birth. It is not necessarily a measure of how good a country’s prenatal or birth skills are, since many children die from car accidents and household accidents and such every year. It can be a useful comparative tool (for instance, is a country better off at keeping its infants from dying from gunshot wounds, or drowning, or cancer, or…?), but it is far from perfect. Especially, as I recently noted, if other countries use different data for their official statistics — for instance, not counting births prior to 26 weeks as live births.

GA 17-47

Still, as you can see, from the chart, there is a huge drop in infant mortality for babies born in each different gestational age bracket, up until “term.” This means a huge difference for babies — the longer they stay in until term, the better their outcomes will be. Here is a partial chart, which shows mortality by gestational age at birth:

imr by gest week

Again, there is a precipitous decline in infant mortality nearly every preterm week, with a majority of babies who were born prior to 24 weeks gestation dying, and a bit better than 50/50 at 24 weeks, with steep drops after that, for each week of gestation. Obviously, the longer these little “buns” can “bake,” the better. That is one reason why this midwife’s work is so astounding and beneficial. Some excerpts from this article include:

Lubic and her team of midwives run a birthing clinic in one of the city’s poorest areas. After 800 babies in eight years, they have never lost a child in childbirth, and has cut the rate of premature births – the biggest risk factor for infant mortality – in half

Her approach is simple. She believes low-income women, many on Medicaid, need the prenatal education that midwives provide. Everything from posture, to nutrition, to how the baby grows…

“Do you think it boils down to just the time you spend with them,” Andrews asked Lubic.

“I think so,” she replied. “I’m convinced that’s what it is. It’s time, respect, its treating people with dignity.”

Here is another chart I put together from the CDC statistics — comparing preterm birth rates by race (black and white only, to keep it simple):

IMR by gest week and race

Up to half of all births (and therefore half of the deaths) in the early weeks were babies born to black women; even though the rate decreased, so that black babies were born at half the rate of white babies by 27 weeks, that’s still disproportionately high. “Preterm birth is the leading cause of death and disability among African American infants.” However, while death rates are still disproportionately high for black babies at term, compared to white babies, they are less dramatic, since the percentage of term births is closer to the national population average (about 13% African-American).

Midwives have better results than doctors, with so-called disadvantaged populations in the U.S., though. Ruth Lubic may may have achieved phenomenal results, but she is not an exception to the rule that midwifery results in better outcomes. So, one question is, why do doctors put up such roadblocks to increasing midwifery care? These are CNMs not CPMs that were studied in this link — yes. But there are still significant difficulties for any midwife to practice. Many are legally restricted, or are politically restricted, from increasing their sphere of influence. For instance, some would want to attend home births, but if they do that, their hospital privileges will be terminated. We don’t see this in Canada, where, in fact, midwives are required to attend both hospital and home births. Obstetricians still attend about 90% of all births in this country, whereas in most other developed countries, midwives are the norm, and OBs are called in only when necessary.

But there is a factor for preterm birth that it not frequently talked about. That factor is previous induced abortion. First, according to the Alan Guttmacher Institute, black women obtain abortions at five times the rate of white women. Although African-Americans comprise only about 13% of the U.S. population, they have 21.4% of all preterm births. This may explain some of the disparity noted above.

Now, for the studies. I did a search through Google Scholar for “‘induced abortion’ and ‘preterm birth'”, and went through the first one hundred studies returned (ten pages, with ten results apiece). Not all of the studies returned were actually about this topic — many only included the search terms tangentially, with the studies themselves being about things as diverse as periodontal disease and smoking — not really about abortion at all. Here is what I found:

  • this abstract from a French study from 1995: “Previous induced abortion was associated with an increased risk of preterm birth (OR 1.4; 95% CI 1.1–1.8); the risk of preterm delivery increased with the number of previous induced abortions (OR 1.3; 95% CI 1.0–1.7 for one previous abortion and OR 1.9; 95% CI 1.2–2.8 for two or more). The relationship was the same for very preterm and moderately preterm deliveries and for spontaneous and indicated preterm deliveries”
  • History of induced abortion as a risk factor for preterm birth in European countries: results of the EUROPOP survey, March 2004 (full study): “Previous induced abortions were significantly associated with preterm delivery and the risk of preterm birth increased with the number of abortions. Odds ratios did not differ significantly between the three groups of countries. The extent of association with previous induced abortion varied according to the cause of preterm delivery. Previous induced abortions significantly increased the risk of preterm delivery after idiopathic preterm labour, preterm premature rupture of membranes and ante-partum haemorrhage, but not preterm delivery after maternal hypertension. The strength of the association increased with decreasing gestational age at birth.”
  • From the Journal of Reproductive Medicine, Feb. 2009: “Induced and spontaneous abortion are associated with similarly increased ORs for preterm birth in subsequent pregnancies, and they vary inversely with the baseline preterm birth rate, explaining some of the variability among studies.”
  • From October 2005, Obstetrical and Gynecological Survey: “A history of induced abortion correlated with an increased risk of very preterm birth (odds ratio, 1.6; 95% confidence interval, 1.2-2.1). There was little change when controlling for maternal characteristics or without adjusting for a history of preterm deliveries. In addition, the association remained the same when women with previous preterm delivery were excluded. The risk tended to increase with the number of previous induced abortions. The adjusted risk of preterm delivery associated with induced abortions tended to be highest for extremely preterm deliveries. The major complications leading to very preterm birth were premature rupture of membranes and idiopathic spontaneous preterm labor, and these occurred more often in connection with extremely preterm birth. Hypertension and fetal growth restriction were more common when infants were born at 28 to 32 weeks gestation. An association between previous induced abortion and very preterm delivery related to fetal growth restriction was apparent in infants born at 28 to 32 weeks gestation.
    “This study shows that a history of induced abortion increases the risk of very preterm birth, particularly extremely preterm deliveries. It appears that both infectious and mechanical mechanisms may be involved.”
  • And again from the Alan Guttmacher Institute, from 2000, a Danish study: “Danish women whose first pregnancy ended in abortion are about twice as likely as those who did not terminate their first pregnancy to subsequently deliver an infant at less than 37 weeks’ gestation, according to results of a population-based cohort study; they have a somewhat elevated risk of having a subsequent delivery at 42 or more weeks of gestation. Analyses of the same cohort also suggest that women who have undergone abortion have twice the risk of other women of later bearing a low-birth-weight infant…
    “When age, residence, interpregnancy interval and number of previous miscarriages were taken into account, women with one previous abortion were 1.9 times as likely as women in the comparison group, those with two previous abortions were 2.7 times as likely and those with three or more previous abortions were 2.0-2.2 times as likely to have a preterm birth. In general, the risk varied slightly according to the method of abortion used, but it was sharply higher (odds ratio, 12.6) among women who had had two abortions by dilation and evacuation. Increases in the risk of preterm birth were significant mainly among women whose interpregnancy interval was 12 months or more; the pattern of risk among this subgroup was similar to the overall pattern. Previous abortion also was associated with a doubling of the odds of very preterm delivery (before 34 weeks’ gestation).”
  • The abstract of this study on precancerous changes in the cervix and subsequent preterm birth matter-of-factly states, “However, because many of the known risk factors for preterm birth, such as sexually transmitted disease, smoking, or prior induced abortion, also are associated with an increased risk of precancerous changes in the uterine cervix, it has been difficult to determine the degree risk due solely to cervical treatment from the degree of risk due to the other risk factors for preterm birth.”
  • The abstract of this Danish study begins, “We have previously shown that induced abortions result in a slightly increased risk of spontaneous abortion and preterm delivery in subsequent pregnancies.” [The study looked at whether the increased risk was perhaps due to a complication from the abortion, but they found that was not the case.]
  • This 2007 study looked at cervical length/shortening in women with multiple prior induced abortions, and found that, “A cervical length of < 25 mm on transvaginal ultrasound is predictive of preterm birth in women with more than one prior induced abortion. Women with multiple prior induced abortions and a short cervix have a 3.3-fold greater chance of spontaneous preterm birth compared with those with a cervical length of 25mm.”

And now more articles and studies that some might question due to pro-life bias, but I think worth reading nonetheless: Endeavour Forum, “Induced Abortion and Later Risk of Preterm Birth,” “Does Induced Abortion Account for the Racial Disparity in Preterm Births, and Violate the Nuremburg Code?“, Open Letter to the U.S. Surgeon General, and AAPLOG’s “Induced Abortion and Subsequent Preterm Birth: General Comments and Summary of the Pertinent Literature.”

In the interest of fairness, not all studies noted the above — perhaps the differences may be part of the reason why midwives have much lower rates of preterm birth among at-risk populations than doctors have. This 1998 study from Hong Kong looked at 118 teenage girls who had had one or more induced abortions.  However, the study was small, and the “control group” (i.e., those who had not had a prior abortion) had a higher-than-average rate of preterm birth, which is more common among teenagers than the pregnant population at large.  It also notes that D&C abortions had been shown to increase rates of future preterm births, and most of these young ladies had suction or medical abortions.

Another Chinese study, this time published in 2001, noted that prior induced abortion (the abstract didn’t note the type of abortion performed) “did not significantly increase the risk of LBW or preterm birth,” although the authors cautioned that this was with a low-risk population, and may not be generalizable.

Next, yet another study from China, this one from 2004, which also found no difference, although there were some odd things I noticed in the discussion. The study looked at mifepristone-induced abortions (RU-486), surgical abortions, and no abortions. Most of the drug-induced abortions were early, about 7 weeks or so; with the majority of the surgical abortions (roughly 60%) performed after 7 weeks but still within the first trimester, and almost all of those were vacuum aspiration abortions. About 1/4 of women who had had drug-induced abortions also had D&Cs performed, and the study said, “The lower risk of preterm delivery among women with a previous mifepristone abortion compared with women with no abortion was confined to women who had mifepristone abortions without postabortion curettage.” I assume that is because the authors recognize and agree that a D&C increases the chance of future preterm birth. Even though this study seems to say that early abortions don’t play a role in future preterm birth, it says, “An early induced abortion with mifepristone and misoprostol without postabortion curettage may produce less trauma to the cervix and the uterus than the mechanical dilation of the cervix and curettage of the uterine wall that takes place in first-trimester vacuum aspiration or postabortion curettage.” That sounds logical — artificially or mechanically dilating the cervix sounds like it could be traumatic to the cervix, and scraping the walls of the uterus sounds fairly traumatic as well. The study noted that many other studies have found an association between prior abortion and subsequent low birthweight or preterm birth; and suggested that, “The age range of the women, the exclusion of women with previous spontaneous abortion and chronic diseases, and the low prevalence of smoking during pregnancy may have contributed to the low rates of preterm delivery and low birth weight in our study. Moreover, the study was undertaken in affluent cities in China; a large number of the participating women were professionals, and they had a level of education well above the Chinese average.

Finally — and the study I think most interesting, since it was 1) the only one that was not Chinese, in case ethnic or cultural differences come into play, or there was somehow biased research in China; and 2) it may actually give a clue as to how to reduce subsequent preterm birth and/or low birthweight in women who have already had abortions — is from this abstract. It said, preterm birth and low birthweight “appeared to be more common, but after logistic regression analysis, we found no evidence of adverse pregnancy outcomes. Induced abortion is not an independent risk factor for adverse obstetric outcome. Marked health behavioral pregnancy risks are associated with prior induced abortions. Health counseling of these women is a challenge, but this objective has not yet been achieved.” And perhaps it is in this that midwives excel, as mentioned above — in getting pregnant women to change their behavior, since they tend to view the pregnancy as a whole-woman condition, not a medical condition, as a life-changing, life-involving event, that needs to be supported with healthy practices, including nutrition and other lifestyle alterations. Midwives are more likely to actually sit down with their clients and talk with them, not just to them, and counsel them. You know how sometimes parents can talk and talk and talk to their kids, and not get any effective behavior changes? And them somebody else comes along, and connects with the kids, and has them eating out of his or her hand, obeying the slightest whim, just because they now want to? We’re human. We need human connections. We’ll do things for people we like and feel a connection or bond with, that we won’t do for others. Perhaps midwives befriend their clients, rather than remaining clinically cold and aloof. Perhaps that is how they get the better outcomes with the same (or worse) at-risk clientele.

2 Responses

  1. Excelent.

    Here is a tool that you use on websites to make people aware of this national issue.

    National Infant Mortality Awareness Month – Spread the word!
    http://www.omhrc.gov/templates/content.aspx?lvl=2&lvlID=195&id=8140

  2. […] Risk Points to Cerebral Palsy. Since this is National Infant Mortality Awareness Month, and since premature birth increases infant mortality, this newest study has implications for this […]

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