Women who repeatedly reject pregnancies may be 'too good' at
carrying, research indicates.
Recurrent miscarriage [RM], defined as three or more
consecutive miscarriages, affects between one and two percent of couples trying
to conceive. In more than 50 percent of cases, the causes of RM are unknown.
Professor Nick Macklon, of the University Hospital
Southampton, who led the UK-Dutch collaborative study, said: 'We have
discovered that [the causes of RM] may not be because [women] cannot carry; it
is because they may simply be super-fertile, as they allow embryos which would
not normally survive to implant'. Implantation is the name for the process
where an embryo attaches to the lining of the uterus, shortly after conception.
The study, published in the journal PLoS ONE, looked at the endometrial
stromal cells (H-EnSCs) of women with a history of RM. H-EnSCs line the uterus
and are actively involved in the process of embryo implantation and may play a 'quality
control' function.
In women unaffected by RM, H-EnSCs were found to regulate
their behaviour in response to the quality of embryo presented. They grew
towards high-quality embryos, but did not when confronted by a low-quality
embryo, thereby ensuring only viable embryos progressed to pregnancy. In
contrast, these cells failed to discern between high- and low-quality embryos
in women with a history of RM.
The authors suggest that in RM this failure of H-EnSC quality
control allows the implantation of poor quality embryos, leading to pregnancy
and, ultimately, miscarriage as fetal development fails.
Professor Macklon said these results offer women 'a clearer
understanding of the causes [of RM], they are not too bad at carrying but
perhaps too good'.
Currently, no treatment options are available to women who
experience RM, but Professor Macklon described these findings as a 'significant
moment for sufferers'.
Dr Siobhan Quenby, from the Royal College Obstetricians and
Gynaecologists, who was not involved in the study, agreed. She told BBC News: 'This
theory is really quite attractive. It is lovely. It's a really important paper
that will change the way we think about implantation'.
The mechanisms underlying the 'quality control' sensor remain
poorly understood, and are expected to be the focus of future research.
Leave a Reply
You must be logged in to post a comment.