>Amniotic fluid was mentioned as an indicator for pollution, but this doesn't
>make sense to me. The only fat in amniotic fluid is vernix, because it
>washes off the baby. The fluid itself will contain whatever water-soluble
>things the mother has ingested, and amniotic fluid takes on the aromas of
>spices.... Amniotic fluid is continuously replenished until the placenta is
>delivered, so I don't see how it can be an indicator for these long-term
>contaminants. Maybe someone out there can enlighten me.
>
>Sandra, did you not have an answer to my question about what portion of the
>contaminant load is transferred to the baby in the first 3, 6, 12 or 48
>months? Is it a constant rate, or is the concentration higher at the
>beginning, and if so, how much higher? And what, if any, difference is
>there in toxin amounts transferred to firstborns, and subsequent children?
>
>Rachel Myr
>Kristiansand, Norway
Rachel, sorry for the long delay.
1) Amniotic Fluid: I don't know exactly how organochlorines find
their way into amniotic fluid, which is distilled from a mother's
blood plasma by the extra-embryonic membranes. Plasma itself has a
certain lipid fraction--less than one percent, as I remember, so
perhaps the contaminants are carried into the uterus this way. ???
This is a good question, and I'd welcome a response by someone better
versed in pharmacokinetics than I. (Judith?)
In any case, the study documenting the presence of pesticides,
dioxins, and PCBs in amniotic fluid is--
W. Foster, "Detection of Endocrine Disrupting Chemicals in Samples of
Second Trimester Human Amniotic Fluid," JOURNAL OF CLINICAL
ENDOCRINOLOGY AND METABOLISM 85(2000): 2954-57.
2) Breast milk contamination over time: Here's what I write in
Chapter Twelve of Having Faith:
"The accumulated period of past breastfeeding...helps to determine
the POP levels in breast milk. The longer a woman nurses, the more
she depletes her body fat of chemical contaminants, and the purer her
milk becomes. After six months of breastfeeding, levels or
organochlorines in breast milk are 20 percent lower than those at the
beginning. By eighteen months, they are half what they are at birth.
One study monitored the milk of a U.S. mother who nursed twins for
three years. By the time of weaning, she had lowered her own body
burden of dioxin by 69 percent. Which is another way of saying that,
during the course of nursing, she delivered to each one of her two
children a third of her own lifetime exposure to dioxin.
"Firstborn children thus receive more chemical contaminants in breast
milk than their younger siblings. One study from Finland found that
the third-born child was exposed to only 70 percent of the PCBs and
dioxins as the firstborn. The eighth, ninth, and tenth children
received only 20 percent as much. Thus, the more children a woman
has nursed, the lower the concentrations of POPs [persistent organic
pollutants] in her breast milk. All other things being equal, a 40
year old mother of one has more contaminants in her milk than a 40
year old nursing her forth child."
In every context, I always make sure to emphasize my own decision to
nurse my children. My first child was born when I was almost 40 and
nursed for more than 3 years. I'm quite sure her body burdens are at
the high end of the scale. However, I did not stop nursing in light
of this knowledge.
citations:
breast milk contamination rises with maternal age: J.M. Albers et
al., "Factors that Influence the Level of Contaminants of Human Milk
with Polychlorinated Organic Compounds," Archives of Environmental
Toxicology 39(1996): 285-91; M. Schlaud, "Organochlorine Residues in
Human Breast Milk: Analysis through a Sentinel Practice Network,"
Journal of Epidemiology and Community Health 49(1995, suppl. 1):
17-21.
contamination falls with cumulated period of nursing: W.J. Rogan and
N.B. Ragan, "Chemical Contaminants, Pharmacokinetics, and the
Lactating Mother," Environmental Health Perspectives 102(1994, suppl.
11): 89-95.
first-born children receive the most: T. Vartianinen, "PCDD, PCDF,
and PCB Concentrations in Human Milk from Two Areas of Finland,"
Chemosphere 34(1997): 2571-83.
--
--
Sandra Steingraber, Ph.D.
Visiting Assistant Professor
Program on Breast Cancer and Environmental Risk Factors
110 Rice Hall
Cornell University
Ithaca, NY 14853
[log in to unmask]
www.steingraber.com
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