Why Prior Abortions Raise Autism Risk

Brent Rooney, M.Sc.

In 1999, Professor Larry Burd and colleagues reported that women with prior induced abortions had a three times higher risk of delivering a newborn later diagnosed with autism.1 In the 1960s, the U.S. autism rate for newborns was approximately 1 in 10,000, but the rate skyrocketed to 1 in 110 in 2009 according to the Centers for Disease Control.

Is it biologically plausible that prior maternal induced abortions elevate a newborn baby’s autism risk? In a word, yes. This is because of two mechanisms — preterm birth (very preterm and extremely preterm) and raised parental age at delivery. Six significant studies report that prior induced abortions boost extremely preterm birth risk (under 28 weeks’ gestation).

Extremely preterm babies have about 25 times the autism risk as do full-term (at least 37 weeks’ gestation) babies.2 The older the parents are at delivery, the higher the autism risk. In a 2001 study of French women, Dr. Henriet reported that French women with more than one prior induced abortion had 2.4 times (i.e. 140% higher) the risk of maternal age over 34 at delivery compared to women with zero prior induced abortions.3

Michael Ganz estimates that the lifetime cost (medical costs + non-medical costs + reduced income) of a U.S. newborn with autism to be $3.2 million.4

Should abortion providers wait for “conclusive” proof of the abortion-autism risk before warning women of a possible increased autism risk? My understanding of U.S. law is that patients must be warned of a serious adverse risk of a treatment for which there is credible evidence (“credible” evidence is well short of so-called “conclusive” evidence). One hundred percent “conclusive” evidence in the field of medical research (in particular, epidemiology) for a purported risk factor does not and can not exist (in statistical jargon, the Gaussian distribution can never provide 100 percent confidence of higher risk or 100 percent confidence of lower risk).

For those who want to dig deeper into the subject of autism, read the 2010 book The Age of Autism (Olmsted & Blaxill). Certainly, the authors much suspect that mercury in vaccines is a likely cause of autism. I suspect that both oral contraceptives and prior induced abortions elevate autism risk; and more generally, that anything that undermines a young woman’s health raises her risk of delivering a newborn later diagnosed with autism.

Brent Rooney, M.Sc., is the Research Director at the Reduce Preterm Risk Coalition, based in Vancouver. This article originally appeared in Justice for Kids Now Bulletin, Feb. 28, 2011. Reprinted with permission.


1. Burd, L. Severud, R. Kerbeshian, J. Klug, MG. Prenatal and perinatal risk factors for autism. J Perinat Med. 1999; 27(6):441-50.

2. Limperopoulos C.  Autism spectrum disorders in survivors of extreme prematurity. Clin Perinatol 2009; 36:791-805.

3. Henriet L, Kaminski M. Impact of induced abortions on subsequent pregnancy outcome: the 1995 French national perinatal survey. BJOG 2001;108(10):1036-1042 [Study Population: French women]

4. Michael L. Ganz . The lifetime distribution of the incremental societal costs of autism. Archives Pediatric Adolescent Medicine 2007;161:343-349.


Why Prior Abortions Raise Autism Risk — 8 Comments

  1. Maybe the vaccination theory isn’t totally wrong, but maybe it was misguided. I definitely believe that abortion is increasing autism and cancer. As far as vaccinations are concerned, I think that there is a direct correlation between vaccinations that contain aborted fetus cells and autism.

  2. You need to get the Age of Autism book reference off here! They are anti vax quacks, and quoting them is going to poison the well of your other research. Stay away from consipracies, stick to the boring research, that’s all we need. Thanks.

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  7. Not all of the increased numbers of babies with autism is caused by abortion. Vaccination has also been implicated. That’s not to say you don’t have a strong case. You do. But you need to mention this, and see if you can figure out what the percentages are. Is the child autistic from birth, or was there a sudden onset after the baby was vaccinated?

    • You are right, of course. Certainly not all cases of autism, nor even a majority of cases, are caused by abortion. Abortion is simply another risk factor, especially because so many studies show that abortion increased the risk of subsequent premature and low birth weight deliveries.

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