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BABIES CONCEIVED THROUGH IN-VITRO FERTILIZATION HAVE HIGHER RISK OF DEATH at birth than those conceived naturally, the results of a new study show.
IVF children are also at an increased risk of being born prematurely and of weighing less at birth, scientists found.
Researchers looked at more than 2,500 women who had conceived both naturally and through IVF and compared the results to more than one million natural conceptions.
They found that babies who had been conceived through IVF were 31 percent more likely to die in the period before and after their birth.
IVF conceived children also tended to weigh an average of 0.9 ounces (25g) less at birth, the findings, published online in the Lancet medical journal show.
The babies also tended to be born earlier, by an average of two days, and were 26 percent more likely to be small for their age.
Dr Liv Bente Romundstad, from the Norwegian University of Science and Technology in Trondheim, who led the study, believes that the high death rate among IVF babies could be linked to the underlying reasons why their mother sought infertility treatment in the first place.
Her results also show that among women who conceived with fertility treatment but also had another child naturally, the spontaneously conceived baby was three times more likely to die than its IVF sibling.
"The adverse outcomes of
assisted fertilisation that we noted compared with those in the general
population could therefore be attributable to the factors leading to
infertility, rather than to factors related to the reproductive
technology," Dr Romundstad said.
Doctors have tried to reduce the safety risks around IVF by cutting the number of embryos they place in the mother's womb.
A maximum of two fertilised eggs are now replaced although many experts
would like to see that number cut to one, to reduce the high number of
IVF twin births.
One in 64 babies in Britain is now born following IVF treatment, official figures released last year show.
American bioethicist Wesley J. Smith commented on the results: "We have
been told repeatedly over the years that IVF babies are just as healthy
as those conceived naturally. Well, it looks like things are not going
as well as we were led to believe". Regarding the effort now to reduce
the number of implanted IVF eggs, Smith comments: "And let's add to
that enacting rules to govern IVF laid down by the Italians: only make
a maximum of three embryos--and implant all that are successfully
created. Had we done that from the beginning and there wouldn't be
400,000 embryos in cold storage today."
[31 July 08, The
Lancet Early Online Publication, The Lancet, "Effects of technology or
maternal factors on perinatal outcome after assisted fertilisation: a
population-based cohort study"; DOI:10.1016/S0140-6736(08)61041-7; The
Lancet DOI:10.1016/S0140-6736(08)61042-9, "Neonatal outcome in
singletons conceived after ART"; 31July 08, Kate Devlin, Telegraph,
http://www.telegraph.co.uk/news/uknews/2474247/IVF-babies-at-increased-risk-of-death-at-birth-study-finds.html;
4August08, London, England, www.LifeNews.com]
Summary: "Effects of technology or maternal factors on perinatal
outcome after assisted fertilisation: a population-based cohort study"
Background
Research suggests that singleton births following assisted
fertilisation are associated with adverse outcomes; however, these
results might be confounded by factors that affect both fertility and
pregnancy outcome. We therefore compared pregnancy outcomes in women
who had singleton pregnancies conceived both spontaneously and after
assisted fertilisation.
Methods
In a population-based cohort study, we assessed differences in
birthweight, gestational age, and odds ratios (OR) of small for
gestational age babies, premature births, and perinatal deaths in
singletons (gestation ≥22 weeks or birthweigh ≥500 g) born to 2546
Norwegian women (>20 years) who had conceived at least one child
spontaneously and another after assisted fertilisation among 1 200 922
births after spontaneous conception and 8229 after assisted
fertilisation.
Findings
In the whole study population, assisted-fertilisation conceptions were
associated with lower mean birthweight (difference 25 g, 95% CI 14 to
35), shorter duration of gestation (2·0 days, 1·6 to 2·3) and increased
risks of small for gestational age (OR 1·26, 1·10 to 1·44), and
perinatal death (1·31, 1·05 to 1·65) than were spontaneous conceptions.
In the
sibling-relationship comparisons, the spontaneous versus the
assisted-fertilisation conceptions showed a difference of only 9 g (−18
to 36) in birthweight and 0·6 days (−0·5 to 1·7) in gestational age.
For assisted fertilisation versus spontaneous conception in the
sibling-relationship comparisons, the OR for small for gestational age
was 0·99 (0·62 to 1·57) and that for perinatal mortality was 0·36 (0·20
to 0·67).
Interpretation
Birthweight, gestational age, and risks of small for gestational age
babies, and preterm delivery did not differ among infants of women who
had conceived both spontaneously and after assisted fertilisation. The
adverse outcomes of assisted fertilisation that we noted compared with
those in the general population could therefore be attributable to the
factors leading to infertility, rather than to factors related to the
reproductive technology.
Dr Liv Bente Romundstad, Department of Obstetrics and Gynaecology,
Norway, St Olavs University Hospital, and the Norwegian Research
Council.
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