(Press-News.org) 30 June 2021: A large cohort study drawn from the national IVF registry of France, which included almost 70,000 pregnancies delivered after 22 weeks gestation between 2013 and 2018, has found a higher risk of pre-eclampsia and hypertension in pregnancies derived from frozen-thawed embryos. This risk was found significantly greater in those treatments in which the uterus was prepared for implantation with hormone replacement therapies. The results confirm with real-life data what has been observed in sub-groups of patients in other studies.
The results are presented today by Dr Sylvie Epelboin from the Hôpital Bichat-Claude Bernard, Paris, at the online annual meeting of ESHRE. The study was performed on behalf of the Mother & child health after ART network, of the French Biomedecine Agency. She said that the results highlight two important considerations in IVF: the potentially harmful effects on vascular pathologies of high and prolonged doses of hormone replacement therapies used to prepare the uterus for the implantation of frozen-thawed embryos; and the protective effect of a corpus luteum (1), which is present in natural or stimulated cycles for embryo transfer. The hormone replacement therapy given to prepare the uterus for embryo transfer, explained Dr Epelboin, suppresses ovulation and therefore the formation of the corpus luteum.
The risk of pre-eclampsia and other pregnancy-related disorders of pregnancy has been raised in a growing number of studies of freezing in IVF.(2) However, the overall risks of maternal morbidity are known to be generally lower in pregnancies resulting from frozen embryo transfer than in those from fresh transfers - except in relation to the risk of pre-eclampsia. While some studies have observed such risks in frozen embryo transfers, few studies, said Dr Epelboin, have compared these "maternal vascular morbidities with the two hormonal environments that preside over the early stages of embryonic development".
This study divided the cohort of pregnancies from IVF and ICSI in the French national database into three groups of singletons for comparison: those derived from frozen embryo transfer in a natural "ovulatory" cycle (whether stimulated or not) (n = 9,500); those from frozen embryo transfer with hormone replacement therapy (n = 10,373); and conventional fresh transfers (n = 48,152).
Results showed a higher rate of pre-eclampsia with frozen embryos transferred in the artificial (ie, prepared with hormone therapy) frozen cycle (5.3%) than in an ovulatory cycle (2.3%) or in fresh cycles (2.4%). The rates were found similarly distinct in pregnancy-induced hypertension (4.7% vs 3.4% vs 3.3%). These differences were statistically significant, even after adjusting for maternal characteristics (age, parity, tobacco, obesity, history of diabetes, hypertension, endometriosis, polycystic ovaries, premature ovarian failure) to avoid bias.
Dr Epelboin and colleagues concluded that the study demonstrates that preparation of the uterus with hormones in an artificial cycle is significantly associated with a higher risk of vascular disorders than from cycles with preserved ovulation and fresh embryo transfers.
The use of frozen embryos has increased in IVF in recent years. Success rates in frozen-thawed embryo transfers are reported to be as or more successful than with fresh embryos and, because frozen transfers appear to reduce the risk of hyperstimulation, it also has safety advantages; the blood pressure risks observed in this study and others do not appear to outweigh these benefits, said Dr Epelboin.
Moreover, because results obtained in an ovulatory cycle appear not to affect the chance of pregnancy, preservation of the ovulatory cycle could be advocated as first-line preparation in frozen embryo transfers whenever the choice is possible.
Presentation 0-182 Wednesday 30 June
Higher risk of preeclampsia and pregnancy-induced hypertension with artificial cycle for Frozen-thawed Embryo Transfer compared to ovulatory cycle or fresh transfer following In Vitro Fertilization
The corpus luteum in pregnancy
The corpus luteum is a naturally developing cluster of cells which form in the ovary during early pregnancy and pump out a pulse of progesterone, a fertility hormone. Progesterone supports the lining of the uterus (endometrium) during pregnancy and improves blood flow.
Embryo freezing and the risk of pre-eclampsia in pregnancy
This is the first large-scale study to identify an association between a hormonally prepared uterus (artificial cycle) and a significantly raised risk of pre-eclampsia in pregnancies following the transfer of a frozen-thawed embryo. Several (but not all) randomised trials of freezing embryos generated from an initial egg collection ("freeze-all") have observed such trends as a secondary endpoint. A substantial review of the literature published in 2018 (Maheshewari et al, Hum Reprod Update 2018) concluded that the evidence in favour of embryo freezing was "reassuring" while adding "a need for caution" from the increased risk of hypertension in pregnancy. Generally, embryo freezing allows several transfers from an initial egg collection treatment (and thereby encourages single embryo transfer and the avoidance of multiple pregnancies) and in freeze-all protocols avoids transfer in the same cycle in which the ovaries were stimulated.
INFORMATION:
* When obtaining outside comment, journalists are requested to ensure that their contacts are aware of the embargo on this release.
This press release is in support of a study report by Dr Sylvie Epelboin presented online at the 37th Annual Meeting of ESHRE.
The tiny beetle Triamyxa coprolithica is the first-ever insect to be described from fossil faeces. The animal the researchers have to thank for the excellent preservation was probably the dinosaur ancestor Silesaurus opolensis, which 230 million years ago ingested the small beetle in large numbers.
In a recently published study in Current Biology, vertebrate palaeontologists from Uppsala University and entomologists from National Sun Yat-sen University (Taiwan), Friedrich-Schiller-Universität Jena (Germany), and Universidad de Guadalajara (Mexico) used synchrotron microtomography to 3D-reconstruct the beetles while they were still trapped within the fossilised faecal matter. The coprolite contained abundant beetle body parts, most belonging to ...
Harpy eagles (Harpia harpyja) - which are among the world's largest eagle species - struggle to feed offspring in heavily deforested areas of the Amazon, according to a study published in Scientific Reports.
Everton Miranda and colleagues found that harpy eagles rely on specific prey that lives in canopy forests, including sloths and monkeys. Eaglets starved in areas of high deforestation where canopy-based food was limited.
The authors observed prey species, how frequently prey was delivered, and estimated the weight of prey in 16 harpy eagle nests in Amazonian forests in Mato ...
ROCKVILLE, MD, USA - June 30, 2021 - Researchers from Sanaria® Inc. and the National Institutes of Health (NIH) are making progress in the development of highly protective malaria vaccines.
In an article published today in Nature, Sanaria's PfSPZ-CVac (CQ) vaccine is reported as being safe and protecting 100% of six subjects against a variant malaria parasite three months after their last dose in the company's Phase 1 safety and efficacy trial. This is the first time complete protection against a variant malaria parasite has ever been achieved that long after vaccine administration.
The ...
Many neurodevelopmental disorders share similar symptoms, such as learning disabilities or attention deficits. A new study from MIT has uncovered a common neural mechanism for a type of cognitive impairment seen in some people with autism and schizophrenia, even though the genetic variations that produce the impairments are different for each condition.
In a study of mice, the researchers found that certain genes that are mutated or missing in some people with those disorders cause similar dysfunctions in a neural circuit in the thalamus. If scientists could develop drugs that target this circuit, they could be used to treat people who have different disorders with common behavioral ...
In 1934, physicist Eugene Wigner made a theoretical prediction based on quantum mechanics that for 87 years went unseen.
The theory suggested how a metal that normally conducts electricity could turn into a nonconducting insulator when the density of electrons is reduced. Wigner theorized that when electrons in metals are brought to ultracold temperatures, these electrons would be frozen in their tracks and form a rigid, non-electricity conducting structure -- a crystal -- instead of zipping around at thousands of kilometers per second and creating an electric current. Since he discovered it, the ...
Researchers have found that eating disorder behaviors, such as binge-eating, alter the brain's reward response process and food intake control circuitry, which can reinforce these behaviors. Understanding how eating disorder behaviors and neurobiology interact can shed light on why these disorders often become chronic and could aid in the future development of treatments. The study, published in JAMA Psychiatry, was supported by the National Institutes of Health.
"This work is significant because it links biological and behavioral factors that interact to adversely impact eating behaviors," said Janani Prabhakar, ...
Neuroscientists at UCL have, for the first time, identified abnormalities in the way memories are 'replayed' in the brains of people with schizophrenia; researchers say the pathbreaking study provides an entirely new basis for explaining many of the condition's core symptoms.
Schizophrenia is a serious and debilitating mental disorder characterised by episodes of psychosis. Symptoms include hallucinations (typically hearing voices), delusions, and disorganised thinking. It affects around 20 million people globally, though the exact cause is unknown.
In the study, published in the journal Cell, researchers used state-of-the-art ...
A new study by investigators from Brigham and Women's Hospital examines the associations between wealth mobility and long-term cardiovascular health. The multidisciplinary study borrowed methodology from the field of economics to analyze longitudinal changes in wealth. The team's results indicate that negative wealth mobility is associated with an increased risk of cardiovascular events, while positive wealth changes are associated with a decreased risk of cardiovascular events. Their results are published in END ...
WHAT:
Two U.S. Phase 1 clinical trials of a novel candidate malaria vaccine have found that the regimen conferred unprecedentedly high levels of durable protection when volunteers were later exposed to disease-causing malaria parasites. The vaccine combines live parasites with either of two widely used antimalarial drugs--an approach termed chemoprophylaxis vaccination. A Phase 2 clinical trial of the vaccine is now underway in Mali, a malaria-endemic country. If the approach proves successful there, chemoprophylaxis vaccination, or CVac, potentially could help reverse the stalled decline of global malaria. Currently, there is no vaccine in widespread use ...
What The Study Did: This crossover trial found that perceived breathing resistance at peak exercise is uniquely and significantly elevated when exercise stress testing (EST) is performed while wearing a mask. Performing EST with a mask yielded lower peak exercise oxygen uptake and heart rates as compared with no mask. However, each experimental condition resulted in peak exercise values that generally remained within normal limits, and no EST required termination due to clinically indicated safety concerns. Thus, although it is possible that wearing a mask exerted a physical limitation on exercise capacity, the clinical relevance of such a possibility is not supported by these data.
Authors: Matthew Kampert, D.O., M.S., ...
