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On terminations and survival rates

Posted in Scientific research, Termination by Matt at WelcometoIllinois on January 24, 2010

I recently wrote about the theory that an increase in the quality of care and medication had contributed to the increased number of children born with Down’s syndrome in the US and UK (along with higher maternal age of course).

A recent study of survival rates of children with congenital abnormalities backs that up. According to a Medscape report based on a story in the Lancet, “medical advances from 1985 through 2003… increased in the likelihood of survival.”

While that seems pretty straightforward another finding of the study has me perplexed.

“Pregnancy termination played a significant role in boosting survival rates. ‘The proportion of terminations of pregnancy for fetal anomaly increased throughout the study period (from 12.4% in 1985 to 18.3% in 2003) and, together with year of birth, was an independent predictor of increased survival,’ the authors write.”

Now I can fully understand how increased terminations of babies with congenital abnormalities would have an impact on the overall infant mortality rate but are the researchers, or the reporter, seriously suggesting that there is a causal relationship between increased terminations and increased survival rates?

The statement “pregnancy termination played a significant role in boosting survival rates” suggests so. As does the headline: “Treatment Advances, Early Terminations Contribute to Higher Survival Rates in Children With Congenital Anomalies”.

I’ve been racking my brains trying to work out how increased terminations could lead to the babies that are born with congenital abnormalities being more likely to live longer, but I can’t see it. Without access to the Lancet report it is hard to tell whether the original research supports the Medscape headline, but my guess is that Medscape has taken a statement that was true for the general population and applied it specifically to the population of children with congenital abnormalities.

3 Responses

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  1. Anonymous said, on May 3, 2010 at 12:41 am

    I just happened past your blog and this post.

    When you say, “my guess is that Medscape has taken a statement that was true for the general population and applied it specifically to the population of children with congenital abnormalities,” do you mean that they are assuming that the increased survival of the general population of infants is similarly reflected in the population of children with congenital abnormalities?

    My thought is that the survival rate of babies with congenital abnormalities is increased because women who did not want to raise such children (or who felt their health and means made them unable to do so effectively) terminated their pregnancies.

    In other words, instead of all pregnancies with fetal abnormalities being carried to term, only those that were actively sought (whether through refusal to test or refusal to abort based on test results) were carried to term. Thus, the infants born were more likely to be cared for under optimal circumstances (since the women who did not want to carry such pregancies to term had already aborted).

    The populations being compared are probably the cohort of infants born with fetal abnormalities before selective terminations became prevalent, and the cohort born after selective terminations became prevalent.

    It may also be that pregnancies more severe abnormalities were more llikely to be terminated, whereas fetuses with less severe abnormalities were more likely to be carried to term (and to survive).

    It’s an interesting study and question.

  2. Anonymous said, on May 3, 2010 at 12:44 am

    Sorry, that should say “pregnancies _with_ more severe abnormalities…”

  3. Maggie said, on December 5, 2010 at 2:30 pm

    Interesting thoughts. Wonder if the researchers ever split the longevity results by those with DS with heart defects and those with DS without heart defects. As for the termination rate – fetal diagnosis of DS via amnio does not provide information on congential defect at all. It merely identifies the presence of the 3rd copy of chromosome 21. So, researchers would have to find out if terminations due to a diagnosis of DS are accompanied by additional tests showing congential malformation OR was just a decision to terminate based on assumed prior knowledge or sharing of medical “knowledge” about DS via doctors (my experience: usually erroneous and/or communicated in a generalized way such that prospective parents are led to believe ALL people born with DS “suffer” from x, y and z conditions). NOT TRUE. [My boys have NO congenital defects. All they have is the extra 21st. No suffering at all!] That said, it seems more likely to me that fetuses carried to term (not terminated) are a representative sample. Those terminated, however, may or may not have survived so we can’t say whether they are a representative sample of potential survivors. AND, we also need to acknowledge that studies of spontaneous abortions show that MOST fetuses with DS spontaneously abort (assumption: have significant enough congenital malformations that they cannot survive). That means that the babies born with DS are the healthiest of those conceived. Terminations may or may not have resulted in a natural spontaneous abortion had the pregnancy continued so we cannot say the same for those. And, I doubt we’ll ever get detailed termination by choice information b/c of privacy choices.

    As for the comment above, only a longitudinal study quantifying the quality of care (including quantity and quality of interventions) broken down by the presence or absence or degree of DS-related health issues would even begin to approach a viable answer to that. Though I’d hypothesize from the increase in longevity and research showing in-home rearing and community and educational inclusion result in the most successful outcomes, that being “wanted” certainly plays a critical role in the lenth and quality of life of a person with DS.

    All fascinating stuff to consider. And the truth is, as each of us strive to have our children with Ds live healthy and happy lives of inclusion, that life span will increase rapidly over the next decade.

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