Pregnancy health centre

New study predicts miscarriage from foetal growth

7^th January 2012 - Evidence linking an embryo’s growth to its risk of miscarriage has been presented at the British Fertility Society Annual Meeting in Leeds. The research, by scientists from the University of Nottingham’s School of Clinical Sciences, also challenges the notion that twins grow more slowly in the womb.

It's hoped the research can go towards developing a new system to identify pregnancies at risk of miscarriage by using evidence of early growth restriction as a factor.

Two theories

Researcher Dr Shyamaly Sur and team tested two hypotheses: whether twins grow more slowly than singletons in the womb and whether restricted growth in the first trimester (from conception until 12-13 weeks) is associated with miscarriage.  

The team tracked the growth of 247 singleton and 264 twin embryos conceived through IVF, allowing them to know the embryos’ precise gestational age.  For each embryo, the crown-rump length (distance from top of the embryo’s head to the bottom of its buttocks) was measured once during the first trimester.

They found that for singleton pregnancies, growth restriction in the first trimester was a sensitive predictor of subsequent miscarriage.  77.8% singleton pregnancies that miscarried were growth restricted but this was not the case in twin pregnancies where only 28.6% of pregnancies that miscarried were growth restricted.

The team also found that in pregnancies resulting in a live birth, twin embryos grew at the same rate as singletons during the first trimester.

Clearest evidence yet

The data show that it may be possible to identify singleton pregnancies at higher risk of miscarriage through accurate measurement of growth during the first trimester.

Dr Sur said in a press release: "Although it has been widely accepted that twin embryos exhibit slower growth in early pregnancy, this hypothesis has not been tested before.  Our work shows that twin embryos actually grow at the same rate as singleton embryos in the early stages of pregnancy.

“Our study also provides the clearest evidence yet that restricted growth in single embryos during the early stages of pregnancy is related to subsequent miscarriage in that pregnancy.

“We hope that this work will go towards developing a new system to identify pregnancies at risk of miscarriage by using evidence of early growth restriction as a factor.  More research is now needed to investigate the relationship between growth and the underlying causes of miscarriage in more detail."

These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.