How many eggs?
BMJ 2004; 329 doi: https://doi.org/10.1136/bmj.329.7461.302 (Published 05 August 2004) Cite this as: BMJ 2004;329:302
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Professors Keirse and Helmerhorst (Editorial August 7th) reassure us
that
neurological consequences following IVF and ICSI twin births are no
greater
than those from natural conception. They make a plea for "only one
fertilised egg in the nest" since morbidity is greater than singleton
births. It is their view that the significant percentage of twins after
IVF
are not successes but overdoses of treatment, ie. "too many eggs in the
same
nest".
In the absence of definitive knowledge as to which fertilised egg has
the
ability to make a child, this blanket criticism is inappropriate. If the
authors are advocating "one for all", one can question are we "all for
one"?
In principle we are, but in practise not.
If the fundamental concept of reproductive medicine is to do one's
best for
all patients with different prospects of pregnancy, and risk of multiple
pregnancy, the answer is surely "no". There is no conflict between
transferring a single embryo for those with a high risk of multiple
pregnancy, and transferring 2-3 for those with a low multiple pregnancy
risk, and low reproductive potential because of age, repeated IVF failures
etc.
That this concept is correct is conclusively shown from our GIFT data
where
the transfer of multiple eggs into the Fallopian tubes in women over 40
who
have not had children, who have a low multiple pregnancy risk has resulted
in a doubling of the live birth rate compared with IVF without any high
order multiple pregnancies. To treat all women the same is not logical
because of biological and clinical variability. Its application will deny
some already disadvantaged couples a singleton child. Surely we should not
condone that?
Competing interests:
None declared
Competing interests: No competing interests
Re: All for one?
We do not share Professor Craft’s reassuring feelings “that
neurological consequences following IVF and ICSI twin births are no
greater than those from natural conception” (Letter August 17th) since a
comparison between bad and bad remains equal. In order to detect an
assisted conception factor, the best comparison we can made is among
singletons. Although the prevalence is low, (very) low birth weight and
(very) preterm birth of singleton pregnancy after assisted conception have
a risk between 2 and 3 relative to those after non-assisted conception.1
The assisted conception factor among twins is apparently overwhelmed by
the multiple conception problem. It is therefore logical to advise to
transfer only one fertilised egg in the nest. We are still waiting on
scientifically sound data that clearly show how we can “identify women who
are likely to have multiple pregnancies and only to reduce the number of
embryos transferred in these.” 2 Professor Craft’s 1988 data 3 reiterated
in his letters published in 1988 4, 2000 5 and 2004 are still not
reassuring us. In this paper we can read that 154 of women 40 years and
older “had 3 or more oocytes transferred and 35 became pregnant. Only 1
had a triplet pregnancy and she miscarried and 5 had twins.” 3 We agree
with Mr Kennedy’s comment in 2000 “that any such scoring system is not
foolproof and that while it may reduce the number of multiples
pregnancies it will not eliminate them and is especially inaccurate among
women over 40. There will be fewer triplets because there are fewer
pregnancies, the proportion does not change-doctors will still get caught
out.” 2
Frans M.Helmerhorst
Marc J.N.C.Keirse
1. Helmerhorst FM, Perquin DAM, Donker D, Keirse MJNC. Perinatal
outcome of singletons and twins after assisted conception: a systematic
review of controlled studies. BMJ 2004;328:261-5.
2. Kmietowicz Z. College urges maximum of two embryos for in vitro
fertilisation. BMJ 2000:271.
3. Craft I, Al-Shawaf T, Lewis P, Serhal P, Simons E, Ah-Moye M, Fiamanya
W, Robertson D, Shrivastav P Brinsden P. Analysis of 1071 GIFT procedures-
the case for a flexible approach to treatment. Lancet 1988;i:1093-8.
4. Craft I, Brinsden P, Lewis P, Ah-Moye M, Fiamanya W, Robertson D,
Serhal P, Al-Shawaf T, Shrivastav P. Multiple pregnancy, selective
reduction and flexible treatment. Lancet 1988;i:1087.
5. Craft I, Podsiadly B, Gorgy A, Venkat G. Number of embryos allowed in
fertility treatment should be flexible. BMJ 2000;320:1672.
Competing interests:
None declared
Competing interests: No competing interests