A recent study from Australia found that, compared with women who conceived naturally, women
undergoing IVF were at significantly higher risk of having a premature, severely
underweight or stillborn baby or one which dies within a few weeks of birth.
The effects were
also found, although to a lesser extent, in ICSI cycles. Overall there was a 2
to 5 fold increase in these complications when babies were conceived following
IVF. Some of these facts were already known from other studies, but what was
revelatory was that conceptions following implantation of a frozen embryo had a
much reduced incidence of complication. For example a baby born after IVF was
over half a pound lighter than a spontaneously conceived baby, but this did not
apply in those babies born after frozen embryo transfer.
In response to this
the authors of the paper postulate that implantation of the embryo transferred
in a fresh stimulated IVF cycle can be compromised by high levels of oestrogens.
These high levels are derived from the use of stimulating drugs, used to boost
the number of eggs produced, and which do not occur when a frozen embryo is transferred
into an un-stimulated or natural cycle. So now we have proof that avoidance of
high oestrogen levels, common practice in conventional stimulated IVF cycles,
will not only reduce health risks for the mother but for the baby as well.
someone who has championed mild and natural IVF for many years I feel
vindicated by these findings. The association of frozen embryo transfer cycles and better outcome has been reported before this, and prompted discussion as to whether freezing all embryos for later transfer should become routine if
conventional stimulation is used. However this is an expensive and unnecessary
option. The logical way to reduce the health risks associated with high
oestrogen levels in IVF, for mothers and babies, is the adoption of mild and
more natural IVF protocols. Babies born following modified natural cycle IVF have been shown to be heavier than those born from conventional IVF, which fits
in with the findings of this study that un-stimulated endometrium is healthier
for the growth of babies. Furthermore, maternal complications such as ovarian
hyperstimulation syndrome (OHSS)can be avoided in mild IVF cycles. Conventional IVF
is still the common form of IVF practiced in the UK but following this study,
it will be increasingly difficult to justify transfer of fresh embryos in
cycles with high oestrogen levels.
findings from the study are also worthy of comment. Women who conceived
following a period of infertility but who were never treated had a higher risk
of unfavourable pregnancy outcomes. However the authors could not confirm
whether the women were self-medicating with fertility drugs or were having
therapies through specialist clinics which might have influenced the outcomes.
Finally, there is
one further important lesson from this study. The Australian team were able to
link the data from women having IVF treatment to their pregnancy and delivery
database, which allowed the correlation of treatment and outcome to be
obtained. In the UK almost 50,000 IVF cycles are carried out each year but no
reliable outcome data is obtained because there is no linkage of the IVF
database to the UK perinatal database. This must be addressed as a matter of