A moving uterus is no simple measure of fertility
A new analysis finds a link between uterine movements and IVF outcomes, but says the evidence is still too weak for clinical practice.
The uterus is constantly moving through small, rhythmic contractions. A systematic review of four IVF studies finds that a higher movement frequency was associated with fewer clinical pregnancies, but stresses that the finding does not yet provide a useful test or treatment.
The movement is known as uterine peristalsis: wave-like contractions of the muscle layer beneath the uterine lining. Researchers have long hypothesised that such movements may affect embryo implantation.
The new review combined four peer-reviewed observational studies involving a total of 863 embryo transfers. In 478 cycles with higher peristalsis, a clinical pregnancy occurred in 33.5 per cent of cases. In 385 cycles with lower peristalsis, the figure was 54.8 per cent.
The researchers calculated a pooled odds ratio of 0.45 for the group with higher peristalsis. This means that the odds were lower in these combined studies. It is not a direct prediction for an individual patient and does not show that the movements caused a treatment to fail.
The authors rated the certainty of the evidence as very low. The studies were small, unblinded and did not always use the same measurement method or threshold. In addition, the measurements were taken at different times around the embryo transfer.
The review did find a consistent association in the available studies, but the statistical prediction for new studies also included the possibility that there is no association. The authors therefore describe peristalsis as a promising, but not yet validated, prognostic marker.
For healthcare, this means that the finding mainly points towards further research. On the basis of this review, there is no sound reason to draw conclusions about an IVF treatment or to alter one. Standardised measurements and research into eventual live-birth outcomes are needed for that.
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- confirmed The review analysed four studies involving 863 embryo transfers. — This is stated in the abstract on PubMed. source
- confirmed Clinical pregnancy occurred in 33.5 per cent of cycles with high peristalsis and 54.8 per cent with low peristalsis. — The figures and percentages appear in the review's results. source
- confirmed The certainty of the evidence was rated as very low. — The authors refer to very low certainty of evidence. source
- confirmed The authors consider the marker not yet validated for clinical use. — The conclusion says that standardisation and prospective research are necessary. source
Editor's note
This is a peer-reviewed systematic review and meta-analysis, but the underlying studies are small and observational. The authors explicitly state that the marker has not yet been validated.Sources
More on this in Dutch media
- de Volkskrant — „ivf vruchtbaarheid”
- RTL Nieuws — „ivf vruchtbaarheid”
- NOS — „ivf vruchtbaarheid”