GM, JE Vena, EF Schisterman, J Dmochowski, P Mendola, LE Sever, E
Fitzgerald, P Kostyniak, H Greizerstein and J Olson. 2000. Parental
consumption of contaminated sport fish from Lake Ontario and predicted
fecundability. Epidemiology 11:388-393.
info about reproductive
of endocrine disruptors..].
et al. have discovered that women trying to conceive
take longer to become pregnant if they have a history
of consuming PCB -contaminated fish caught in Lake Ontario.
graph to the right indicates that the longer the history of
fish consumption by potential mothers, the less likely is
a conception in any given month of trying to conceive. Each
curve describes the likelihood of conception for women who
have different patterns of fish consumption. A lower curve
means a lower likelihood of conception.
from Buck et al. 2000.
likelihood of conception also decreases as time (in months)
goes on, for women who have failed to conceive up to a given
month. This is likely to be a statistical result of the
fact that as time goes on, women who can conceive do and
the pool of potential mothers is increasingly dominated
by women with fertility impairments.
did they do?
Buck et al. interviewed women in a study cohort of anglers
and partners of anglers (the New York State Angler Cohort Study),
ascertaining time to pregnancy (TTP) for the most recent pregnancy.
They restricted the sample to the women who reported having stopped
use of birth control and for whom information was also available,
for the women and their partners, about fish consumption.
the interview, Buck et al. also gathered information about
smoking, prior experience with infertility, or other relevant gynecologic
problems and treated these as potentially confounding variables
in their statistical analysis.
did they find?
28% of the sample reported conception during the first menstrual
cycle of trying to become pregnant. 81% reported requiring 6 or
fewer months to conceive, whereas 9% required 13+ months.
length of time that mothers had eaten Great Lakes fish prior to
attempting to conceive was associated with an increased latency
to pregnancy. In everyday terms (which the article studiously avoids),
the longer mothers had been eating Great Lakes fish, or the more
they had eaten, the less likely it was that they would become pregnant
during a given menstrual cycle. They found no comparable pattern
for the father's fish consumption.
et al. caution that their study, while highly suggestive,
"should be considered preliminary" because the data on
time to pregnancy and fish consumption were from retrospective interviews
and thus subject to recall error, and because their data on potential
confounding variables was limited.
also note that while fish consumption was associated with longer
time to pregnancy, all the women in the study eventually became
pregnant. Their sampling procedure may unintentionally have excluded
completely infertile couples. Hence the population consequences
study does reveal one unambiguous fact: that despite years of
public education efforts to discourage people from eating contaminated
fish, people continue to do so, including women of child-bearing
age. "Among the angler couples in this study who were attempting
pregnancy, 42% of women and 68% of men of reproductive age reported
ever having eaten Lake Ontario fish despite state advisories warning
women of reproductive age not to eat any fish from Lake Ontario...
fish consumption advisories for Lake Ontario have been issued in
New York State since 1976" yet "only 49.9% of Great Lakes
sport fish consumers were aware of health advisories."