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 The increased risk of complications may be due at least in part to
advanced maternal age and other health factors that lead women to
try assisted reproductive technology (ART) in the first place, say
authors of both studies published today in Pediatrics. They also
caution that the findings are too preliminary to deter women from
trying to conceive this way.
“At this point in time, we don’t believe the weight of the available
evidence is strong enough to suggest that women should not proceed
with ART,” Melissa Bondy, an oncology researcher at Baylor College
of Medicine in Houston who wrote an editorial accompanying the
cancer study, said by email.
That’s because the cancer study, like a lot of other research
exploring the roots of birth defects and childhood disease, couldn’t
randomly assign some women to try ART just to see how their children
turned out.
Instead, the researchers mined data from birth records for all
children born in Norway between 1984 and 2011, pairing it with
cancer registry data. The study included more than 1.6 million kids,
including almost 26,000 conceived with ART.
Out of about 4,500 cancers, 51 occurred in ART-conceived children.
Overall cancer risk wasn’t significantly greater for the ART kids,
but the technology was linked to 67 percent higher odds of leukemia.
It was also tied to nearly four times the risk of Hodgkin’s
lymphoma, though this was based on just three cases among the ART
kids.
“Since some childhood cancers, such as leukemia, appear early in
childhood, it is thought that factors related to early embryonic
development or intrauterine environment may play a role,” said lead
author Dr. Marte Reigstad of the University of Oslo.
“What these factors are, we still know little about, but there are
some indications that, for example, high parental age may play a
part, as well as some rare hereditary genetic diseases,” Reigstad
added by email.
The second study examined another potential risk of ART –
developmental delays – by looking at Massachusetts children enrolled
in Early Intervention (EI), a program that serves infants and
toddlers with disabilities.
Researchers linked birth records for more than 330,000 deliveries
from 2004 to 2008 with data on more than 88,000 children referred to
EI for services.
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After excluding multiples, there were about 318,000 singleton
births, including about 6,450 conceived with ART and another 5,500
born to couples that struggled to conceive.
Compared to offspring of couples without any fertility issues,
ART-conceived babies were 27 percent more likely to get EI
referrals, while infants born to so-called “subfertile” couples that
struggled to conceive had 20 percent higher odds.
Because ART infants are more likely to arrive early and preemies may
be more likely to enroll in EI programs, researchers adjusted the
results to account for preterm deliveries.
“The results from our study suggest that prematurity is not the
primary contributor through which ART is associated with EI
enrollment,” said lead author Dr. Hafsatou Diop of the Massachusetts
Department of Public Health.
“While there is an increased risk, we don’t necessarily think that
it is enough to influence one’s decision about whether or not to
proceed with ART,” Diop added by email.
Even though some risk may stem from factors like age or pre-existing
medical conditions that women can’t change, there’s still plenty
that women can do to lower the odds of pregnancy complications and
resulting developmental delays no matter how their children are
conceived, Diop noted.
“It is important to achieve and maintain optimal health prior to
conception – this includes stopping smoking and drinking, reducing
stress, maintaining a normal weight for height and eating well,”
Diop said.
SOURCE: http://bit.ly/1qyV1oi Pediatrics, online February 4, 2016.
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