Department of Obstetrics & Gynaecology, University of Aberdeen, Aberdeen Maternity Hospital, Aberdeen AB25 2ZD, Scotland, UK
There has been much concern over the years about the health of children born following assisted reproduction and whether they are at increased risk of abnormality. Most recently this concern has focused around children born to infertile fathers following intracytoplasmic sperm injection (ICSI) and a number of important follow-up studies are underway. However any putative risks in this respect pale into insignificance when compared with the morbidity in children born of high order multiple pregnancy. Even twins, generally regarded as a happy outcome of IVF, run increased risks of dying or ending up with handicap, compared with singleton pregnancies (Bergh et al., 1999). How can doctors, rightly concerned with the welfare of their patients and their offspring, have allowed this? It is disappointing that in the UK, with so much discussion and debate about the welfare of the child, the greatest risk to the health of the child, namely the risk of being born premature, continues to be regarded in many quarters as something of a side issue.
Perhaps the current situation reflects the pressures induced by commercially driven medical practice. Concerns surrounding success rates and competition for patients, as well as professional livelihood and status may have distorted a clear assessment of acceptable and appropriate risks following assisted reproduction. It is possible that some doctors, specialising in infertility treatment and not having been near a labour ward or neonatal unit for some time, do not remember the risks associated with multiple pregnancy. It is also possible that some remember happy outcomes and believe that the risks are exaggerated. It may even be possible that some do not think that the risks apply to their patients, including particularly their older patients (despite evidence of even worse outcomes among women in their 40s having triplets). In all these situations there is clear evidence of denial, and that denial is predicated by an uncertain justification for multiple embryo replacement based on erroneous perceptions of actual and expected success.
So what more can be done. In the UK, to be fair, there has been some movement. The number of two-embryo replacements is increasing, but there is no evidence yet of a fall in multiple birth rates and particularly triplet rates. There are considerable regional variations in practice, undoubtedly influenced by the provision of care and the views of opinion leaders. Several private clinics in London generate more triplets in 1 year than does the whole of Scotland. Recent guidelines from the Royal College of Obstetricians and Gynaecologists (RCOG) recommending two-embryo replacements in all women aged <40 years seem destined to be ignored unless adopted by Health Authorities. British Fertility Society recommendations have been in place for some time, but have had little effect. The Human Fertilisation and Embryology Authority (HFEA) seems reluctant to interfere with `clinical freedom', although it does have a concern for the welfare of the child.
Colleagues in Scandinavia have yet again shown the way forward (Hazekamp et al., 2000) and are already into a serious discussion about one-embryo replacement (in attitude and practice, they seem light years ahead of the situation in the UK). If good embryo cryopreservation rates can be maintained or improved, then one-embryo replacement must be the way forward. In the long run, it may be the best thing not just from the point of view of mother and child, but may also address the success rates issue. Clearly more work is needed, but a number of important studies are now under way. Some have already been reported and indicate comparable or enhanced cumulative pregnancy rates from serial one-embryo transfers (Gerris et al., 1999
; Vilska et al., 1999
). There is some biological sense. If a uterus is receptive, then all viable embryos may implant, but if the uterus is not receptive, none will implant, no matter how many are replaced. Putting back fewer embryos more often gives the uterus more opportunities to be receptive.
As Dr Nygren, one of the authors of the Swedish follow-up study tells his patients, `you can have as many embryos put back as you like one at a time'.
Notes
1 To whom correspondence should be addressed at: Department of Obstetrics & Gynaecology, University of Aberdeen, Aberdeen Maternity Hospital, Aberdeen AB25 2ZD, Scotland, UK. E-mail: allan.templeton{at}abdn.ac.uk
This debate was previously published on Webtrack, May 17, 2000
References
Bergh, T., Ericson, A., Hillensjo, T. et al. (1999) Deliveries and children born after IVF treatment in Sweden 19821995 a complete cohort study. Lancet, 354, 15791585.[ISI][Medline]
Gerris, J., De Neubourg, D., Mangelschots, K. et al. (1999) Prevention of twin pregnancy after in-vitro fertilization or intracytoplasmic sperm injection based on strict embryo criteria: a prospective randomized clinical trial. Hum. Reprod., 14, 25812587.
Hazekamp, J., Bergh, C., Wennerhold, U.-B. et al. (2000) Avoiding multiple pregnancies in ART: consideration of new strategies. Hum. Reprod., 15, 12171219.
Vilska, S., Tiitinen, A., Hyden-Granskog, C. and Hovatta, O. (1999). Elective transfer of one embryo results in an acceptable pregnancy rate and eliminates the risks of multiple birth. Hum. Reprod., 14, 23922395.