In my previous article I discussed mercury and vaccines as possible causes of autism. Now, I will look at elements that babies are exposed to in the womb that may predispose them to getting autism.
Mercury Amalgam Fillings
Mothers who have mercury fillings, which contain 50 percent mercury, when pregnant, or who have them before pregnancy, may have an increased risk of having a child with autism. Although mercury fillings have been used for more than 150 years, the safety of such a practice was not studied until recently.
A review published in 2009 found that:
"Mercury from maternal amalgam fillings leads to a significant increase of mercury concentration in the tissues and the hair of fetuses and newborn children. Furthermore, placental, fetal, and infant mercury body burden correlates with the numbers of amalgam fillings of the mothers. Finally, mercury levels in amniotic fluid and breast milk correlate significantly with the number of maternal dental amalgam fillings." (1)
So pregnant women who have mercury fillings could end up leaching mercury into their amniotic fluid and passing it through the placenta to give their babies' bodies burdensome amounts of mercury before they are even born.(6)
If the mother has the fillings removed during pregnancy, this can make the situation worse and cause more mercury to be released. When she begins to breast feed, her baby gets additional mercury from the milk. A study in sheep found that after ewes were given new amalgam fillings and they nursed foster lambs, the lambs received some of this mercury.
"Neonatal uptake of mercury (Hg) from milk was examined in a pregnant sheep model, where radioactive mercury (Hg203)/silver tooth fillings (amalgam) were newly placed. A crossover experimental design was used in which lactating ewes nursed foster lambs. Results from the animal studies showed that during pregnancy, a primary fetal site of amalgam Hg concentration is the liver and after delivery, the neonatal lamb kidney receives additional amalgam Hg from mother's milk. It was concluded that Hg originating from maternal amalgam tooth fillings transfers across the placenta to the fetus, across the mammary gland into milk ingested by the newborn, and ultimately into neonatal body tissues." (2)
Anti-D injections are given to rhesus (Rh) negative mothers during pregnancy to reduce the risk of fetal Rh (positive blood mixing with theirs and causing an immune system reaction). This is called rhesus disease or feto-maternal haemorrhage.
This can occur during childbirth but mainly occurs if the mother has had an invasive medical procedure such as amniocentesis or chorionic villus sampling. Feto-maternal haemorrhage can cause the baby to become anemic and need an in utero blood transfusion, which carries a 2 percent risk of fetal death. (3,4)
However, some brands of anti-D injection used to contain mercury and it has been implicated as a possible cause of autism. A 2008 study by the Institute of Chronic Illnesses found that Rh-negative mothers were much more likely to have children with neurological disorders, compared with Rh-positive mothers.
Thimerosal was removed from the U.S. anti-D injections in 2002 and researchers discovered that the children born in 2002 or later had the same risk of neurological disorder as those in the Rh-positive group, but those before 2002 had a higher risk, suggesting that the anti-D injection was the causative factor.
"There were significant and comparable increases in maternal Rh-negativity among children with NDs (Clinic: A=24.2 percent), autism spectrum disorders (Clinic: A=28.3 percent, B=25.3 percent), and attention-deficit-disorder/attention-deficit-hyperactivity-disorder (Clinic: A=26.3 percent) observed at both clinics in comparison to both control groups (Clinic: A=12.1%, B=13.9 Percent) employed. Children with NDs born after 2001 had a maternal Rh-negativity frequency (13.6 percent) similar to controls." (5)
Removing the mercury from anti-D injections seemed to be a positive step in reducing the number of children with autism and ASDs.
1. A prospective study of prenatal mercury exposure from maternal dental amalgams and autism severity, Acta Neurobiologiae Experimentalis. Acta Neurobiol Exp 2009, 69: 1–9.
2. Vimy MJ et al., Mercury from maternal "silver" tooth fillings in sheep and human breast milk. Biol Trace Elem Res.1997 Feb;56(2):143-52. Abstract:
3. Birth Defects, Rh Disease, March of Dimes. Web. 9 September 2011. http://www.marchofdimes.com/birthdefects_rh.html
4. A156 Pregnancy (rhesus negative women) - routine anti-D (review): guidance, National Institute for Health and Clinical Excellence. Web. 9 September 2011.
5. Neurodevelopmental disorders, maternal Rh-negativity, and Rho(D) immune globulins: a multi-center assessment, Neuroendocrinology Letters. 2008 Apr;29(2):272-80. Abstract:
6. Lugliè PF et al. Mercury determination in human amniotic fluid. Minerva Stomatol. 2000 Apr;49(4):155-61.
Joanna is a freelance health writer for The Mother magazine and Suite 101 with a column on infertility, http://infertility.suite101.com/. She is author of the book Breast Milk: A Natural Immunization, and co-author of an educational resource on disabled parenting.
She is a mother of five who practised drug-free home birth, delayed cord clamping, full term breast feeding, co-sleeping, home schooling and flexi schooling and is an advocate of raising children on organic food.
Reviewed September 21, 2011
by Michele Blacksberg RN
Edited by Malu Banuelos