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 Infertility has long been linked to an increased risk of premature
deliveries and underweight babies, and the current study offers
fresh evidence of this. Compared to babies conceived naturally,
infants born after women used assistive reproductive technology
(ART) were slightly more likely to be born preterm and weighed an
average of 60 grams (2.1 ounces) less, the analysis of more than
65,000 births found.
But the difference was less dramatic when researchers compared only
the 2,776 babies conceived with ART to their 1,245 siblings
conceived the old-fashioned way. Now, the ART siblings had an even
smaller increased likelihood of being preemies and weighed an
average of just 31 grams (1.1 ounces) less than their
naturally-conceived brothers and sisters.
"As a group, children born after medically assisted reproduction
are, in absolute terms, at increased risk of adverse birth
outcomes," said lead study author Alice Goisis of the London School
of Economics and Political Science.
"But the results of this study indicate that this elevated risk is
likely attributable to factors other than the treatment itself,"
Goisis said by email.
Pregnancy normally lasts about 40 weeks, and babies born after 37
weeks are considered full term.
In the weeks immediately after birth, preemies often have difficulty
breathing and digesting food. They can also encounter longer-term
challenges such as impaired vision, hearing and cognitive skills, as
well as social and behavioral problems.
All of the babies in the current study were born in Finland between
1995 and 2000.
Overall, the ART-conceived babies were more likely to be first-born
children compared to naturally-conceived babies (62 percent versus
38 percent), and more likely to be part of a multiples pregnancy (21
percent versus 2 percent), with mothers who tended to be older,
better educated and less likely to smoke during pregnancy, the
researchers report in The Lancet.
Within families, the differences in birth outcomes for siblings
conceived with and without ART were negligible once researchers also
accounted for birth order and any multiple pregnancies.
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The study wasn't designed to prove whether or how ART might directly
contribute to preterm births or underweight babies. But, the study
team writes, it's possible that effects of the ART treatments or
characteristics of the parents could also explain some of the
associations.
It's also possible that parents able to have at least one baby
without ART might use less invasive treatments to conceive than if
they were only able to have a baby with help from reproductive
technology, the study authors note. Researchers lacked data to
distinguish all invasive IVF treatments from less invasive
alternatives.
"A history of infertility, whether in female or male, can in itself
denote risk for the baby because what causes infertility can be
associated with adverse genetic traits inherited by the next
generation," said the co-author of an accompanying editorial, Dr.
Norbert Gleicher of the Center for Human Reproduction in New York
City.
"Moreover, if these traits prevent pregnancy or live births,
populations that do not get treatments to overcome these traits (IVF
included), of course, do not transmit these traits," Gleicher said
by email.
Essentially, this means it will take several generations to get a
better picture of the risks of IVF, and how these risks might differ
based on parents' unique characteristics, Gleicher said.
"The question in medicine is always to find the right balance
between risk and benefit," Gleicher added. "And if this is done, IVF
has to be viewed as a probably unprecedented success."
SOURCE: https://bit.ly/2sUPzm6 and https://bit.ly/2G9Sxew The
Lancet, online January 14, 2019.
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