https://www.washingtonpost.com/news/to-your-health/wp/2015/12/14/maternal-exposure-to-anti-depressant-ssris-linked-to-autism-in-children/
A
new study provides some of the strongest evidence yet that using
an antidepressant like Prozac, Paxil or Zoloft during the final two
trimesters of pregnancy may be linked to a higher risk of autism
spectrum disorder for the child.
Selective serotonin
reuptake inhibitors (SSRIs), the most commonly
prescribed antidepressants, work by influencing naturally occurring
chemical messengers in our brains.
The research,
published in JAMA Pediatrics on Monday, involved the analysis of health
records in Quebec from January 1999 and December 2009. During that
time 145,456 full-term singleton infants were born, and 1,054 or 0.72
percent were subsequently diagnosed with autism. The average age at
first diagnosis was 4.6 years and the average age of children at the end
of follow-up was 6.2 years. Boys with autism outnumbered girls 4 to 1.
Researchers
identified 4,724 infants (3.2 percent) who were exposed to
antidepressants in utero, with 4,200 exposed ruing the first trimester;
2,532 during the second and/or third trimester.
Of the first group, 40 were diagnosed with autism and in the latter group 31 were diagnosed with autism.
When
taking into account maternal depression as a factor, that translates to
no association for use of antidepressants in the first trimester but an
87 percent increased risk when used in the second or third trimester,
Anick Bérard, a researcher at the University of Montreal, and co-authors
wrote.
The researchers said that there may be several mechanisms
at work that explain the phenomenon and it has to do with how serotonin
impacts brain development. Scientists believe that the capacity of the
brain to synthesize serotonin develops atypically in children with
autism.
Due to the fact that antidepressants are "likely to
remain widely used" in the future, "a better understanding of the
long-term neurodevelopmental effects of [antidepressants] on children
when used during gestation is a public health priority," Bérard wrote.
Doctors
have long had mixed feelings about prescribing antidepressants to
pregnant women. Previous studies have shown an increased risk of
spontaneous abortion, prematurity and other physical issues and the U.S.
Food and Drug Administration has wanted that one drug, Paxil, may
increase the risk of birth defects.
But many doctors have tended
to weigh the harms of maternal depression — which may lead to poor
nutrition, avoidance of medical care among other issues — as potentially
more directly damaging to a fetus than the drugs.
The new study may shift the conversation.
"What
this tells us is that we need to think even more carefully about the
prenatal environment. And not just about birth defects you can see at
the time of delivery but about longer-term consequences," said Susan
Hyman, a former chairperson of the American Academy of Pediatrics
committee on autism, who is not affiliated with the study.
Surveys
have shown that the use of SSRIs in pregnant women is rising in the
United States — from less than 6 percent in 1999 to 13 percent in 2003 —
and Hyman emphasized that the overwhelming majority of them do not have
children with autism spectrum disorders.
"We would not want
people to feel guilty," said Hyman, a professor of neurodevelopmental
pediatrics at the University of Rochester Medical Center. "That is
something that is not productive."
Scientists believe
SSRIs balance the level of serotonin, which boosts mood for the mother.
But the drugs also cross the placental barrier and the effect of such
drugs on the brain development of a fetus at its earliest and
more vulnerable state is still being studied.
The JAMA Pedatrics
research adds to the growing number of studies about antidepressant and
developmental delays, autism or Attention Deficit Hyperactivity Disorder
(ADHD) — but the picture is far from clear as the results have been
mixed.
From a study design standpoint, the new study is stronger
than some of the previous work because it is prospective, taking
information about the pregnancies before they knew the outcome. But it
has a number of limitations. First, the study used prescription filling
data to determine which women were on antidepressants, but they may or
may not have actually taken them. Perhaps more importantly, the data
didn't have information about lifestyle, and it's possible that myriad
factors, such as whether they smoke or their body mass index, may have
influenced the findings.
Last
April, Johns Hopkins University researchers reported in the journal
Pediatrics that boys with autism were almost three times as likely to
have been exposed to SSRIs than their typically developing counterparts.
The team, which looked at nearly 1,000 mother-child pairs, found that
the effect appeared to be stronger in those exposed during the first
trimester and in boys than girls. A similar link was seen between a
mother's SSRI use and developmental delays, but the sample was smaller
and the researchers said those results should be interpreted with
caution.
In another study, Harvard scientists analyzing
electronic medical records reported that children who were exposed to
antidepressants in the womb were at 80 percent increased risk of ADHD.
However,
that same study found that children were not more likely to have autism
spectrum disorders when accounting for a mother's medical history. That
is, mothers with a history of psychiatric illness were more likely to
have a child with autism regardless of whether or not they are on
medication.
So if you're on antidepressants and pregnant or thinking about getting pregnant, what should you do?
Hyman
said that it should still remain an individual decision, but that
prospective mothers might want to have a serious discussion with their
doctor about the possibility of other types of therapies for depression
and anxiety, such as counseling.
Bryan H. King, a doctor at
Seattle Children’s Hospital, had similar advice, writing in an editorial
accompanying the study that "it makes no more sense to suggest that
[antidepressants] should always be avoided than to say that they should
never be stopped."
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