Dr Raphaël Hirt, a Fellow in the Division of Reproductive Medicine at the Hôpital Antoine Béclère, Clamart, Paris (France) headed by Professor Renato Fanchin, told the conference that the finding would help medical professionals and women make objective decisions about how many embryos should be transferred in one IVF attempt.
“Twin pregnancies account for between a quarter and a third of pregnancies obtained during IVF, and eight per cent of them are complicated by the babies being born extremely premature, leading to medical complications and sometimes foetal mortality,” he said. “For this reason, single embryo transfer is promoted as the best way of avoiding twin pregnancies, but, in some cases, this can alter the overall likelihood of pregnancy. An evaluation of a woman’s individual risk of perinatal adverse outcomes from a twin pregnancy may help to select those women who have a lower risk of having twins born severely prematurely and who could consider a double embryo transfer if that is what they want.”
Dr Hirt and Prof Fanchin knew that women who already had children were less likely to give birth prematurely, probably because the uterine cavity had been distended by previous pregnancies. They decided to see whether the height of the uterus, as measured by transvaginal ultrasound (a process called hysterosonometry or HSM) could predict the outcome of twin pregnancies after IVF.
They used HSM to measure the distance between the top of the uterus (the fundus) and the external opening of the cervix (cervical os) in 79 women, aged 21-39, who were attending their clinics for fertility treatment. After successful IVF treatment they followed the women to record gestational age at delivery, prevalence of severe prematurity (defined as delivery before 32 weeks) and foetal mortality.
They divided the women up into three groups based on the 30th and 70th centile of the HSM results: group 1 (24 women with a uterus height less that 63mm), group 2 (33 women with an average size uterus of between 64-70mm) and group 3 (22 women with a uterus height greater than 70mm).
They found that women with the smallest uteri (group 1) were significantly more likely to have babies born severely premature, with an increased number of foetal deaths, compared to the other two groups. The average gestational age of babies in the group 1 women was 33.7 weeks (with a range of 23-38.5 weeks) compared to an average age of 37.5 weeks for the other two groups. There were seven foetal deaths in the first group compared with one in the second group and none in the third group, and six of the deaths in the first group were linked to prematurity, while the one death in the second group was not.
After adjusting for any confounding factors such as age, parity, previous premature delivery, the researchers found a clear association with HSM.
Dr Hirt said: “This is the first time that uterine length has been used to predict which women are more likely to have twins born prematurely. Our results show that HSM is a reliable and non-invasive method for predicting twin-related severe prematurity and neonatal mortality, and it can be used before conception to help with objective decision-making about the number of embryos to transfer. For women with an HSM measurement of less than 62mm, a single-embryo transfer is indicated, but in those with a longer uterine cavity, a double-embryo transfer can be considered if it is acceptable to the patients.
“Transvaginal ultrasound is a common, easy and inexpensive examination. Furthermore, it is already practiced in many fertility clinics and would not increase IVF costs. Although we suggest that further, larger studies should be conducted, we believe that even with the restricted number of patients in our study, the results are dramatically significant and HSM could be included in the criteria that clinics currently use when advising about the number of embryos to transfer.”
Dr Hirt and Prof Fanchin’s team will be using HSM as new criteria and will be studying whether this results in a significant decrease in foetal mortality. They are also planning to study the impact of a short uterine cavity on singleton pregnancies, to see whether it could help to identify those women who will need intensive neonatal care.
Sarah De Potter | alfa
Rabies viruses reveal wiring in transparent brains
19.01.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn
On track to heal leukaemia
18.01.2017 | Universitätsspital Bern
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
19.01.2017 | Earth Sciences
19.01.2017 | Life Sciences
19.01.2017 | Physics and Astronomy