IVF embryos that are more likely to successfully implant may be identified in the future with DNA fingerprinting, scientists have discovered. The research team hope that this method can be utilized to enhance the chances of pregnancy using IVF.
The international research team tested the DNA of embryos before they were implanted into the womb in an IVF procedure. These results were then compared with the DNA of those healthy babies that were born. The team identified a cluster of genes that may be of use in identifying the embryos that are more likely to make it to full term. Currently, no accurate method exists to identify viable embryos, other than crude methods, such as looking at the shape of the embryo.
“DNA fingerprinting is the ultimate form of biological identification, but until now it has not been used to identify the embryonic origin of resultant babies born following embryo transfer; nor has it been used for gene expression studies,” explains one of the researchers, David Cram (Monash University, Victoria, Australia). He adds, “We have developed a novel strategy of utilizing a combination of blastocyst biopsy, DNA fingerprinting and microarray analysis to identify viable blastocysts among the cohorts transferred to patients.”
Cram and his coworkers looked at 48 women who were to undergo IVF. They removed 8–20 cells from the trophoblast, amplified their DNA and observed their gene expression using microarray analysis. In total, 25 of these women went on to become pregnant, giving birth to a total of 37 babies. The infants then had blood taken from their umbilical chord or swabs were taken from their cheeks so that each infant could be DNA fingerprinted. These results were compared with that from the embryos so that the embryos that developed into healthy infants could be identified.
The team identified a cluster of genes that appeared to be present in the viable blastocysts. Gayle Jones (Monash University, Victoria, Australia) hopes that they can narrow the identification process down by coming up with a smaller subset of genes that uniquely identify viable embryos. She adds, “The ability to select the single most viable embryo from within a cohort available for transfer will revolutionize the practice of IVF, not only improving pregnancy rates but eliminating multiple pregnancies and the attendant complications.”
The team believe that this process will identify viable embryos, which has been one of the major hurdles of IVF, and therefore increase the rate of healthy births.
Source: Jones GM, Cram DS, Song B, Kokkali G, Pantos K, Trounson AO. Novel strategy with potential to identify developmentally competent IVF blastocysts. Hum. Reprod. (2008) (Epub ahead of print).
Conference to mark 30 years of IVF in the UK
The annual National Infertility Day conference will be held in London, UK, on the 19th July this year to mark the 30th anniversary of the first IVF birth. Robert Edwards, one of the pioneers of IVF, will be the opening speaker. Andre Van Steurtghem, the pioneer of intracytoplasmic sperm injection will also be speaking.
A total of 30 distinguished speakers will be delivering speeches at the conference, which will be held at the New Connaught Rooms in central London. Topics being discussed will include donor issues, male and female infertility, new developments (including in vitro maturation) and the issue of single-embryo transfer. In addition, topics such as nutrition, adoption, surrogacy and Chinese medicine will also be discussed.
National Infertility Day is intended to raise awareness and provoke debate on the many topics related to the subject. In addition, it provides an opportunity to bring together infertility patient associations, health professionals and patients for probably the largest, most comprehensive infertility conference.
Chief Executive of Infertility Network UK and Chair of the Organizing Committee of National Infertility Day, Clare Brown, said: “This day will recognize how treatments, which 30 years ago were seen as possibly going beyond the mark, are now recognized treatments for infertility. It’s a shame that the NHS in many areas still, after 30 years, do not seem to see them as such. We hope that this Day will show the opposite.”
Source: www.nationalinfertilityday.com
Safety of tap water for pregnantwomen questioned
Pregnant women may be putting their babies’ health at risk by drinking water that has been disinfected with chlorine, a recent study revealed. The study, published in Environmental Health, suggested that drinking water containing byproducts of water chlorination may increases the risk of the child having heart problems, cleft palate or major brain defects.
Almost 400,000 Taiwanese infants were included in the study, which was the first to link these three birth defects with the byproducts of water chlorination.
Although an effective method of reducing waterborne disease occurrence, water chlorination results in the presence of several chlorination byproducts in the water, according to several studies. Juni Jaakkola (University of Birmingham, Birmingham, UK) and her team studied data on the infants, investigating whether tap water with high, medium or low chlorination byproduct levels had any effect on the occurrence of 11 common birth defects.
The team found that the risk of ventricular septal defects, cleft palate and anencephalus was increased substantially with exposure to high levels of chlorination byproducts.
“The biological mechanisms for how these disinfection byproducts may cause defects are still unknown,” adds Jaakkola. “However, our findings don’t just add to the evidence that water chlorination may cause birth defects, but suggest that exposure to chlorination byproducts may be responsible for some specific and common defects. Whilst the benefits of water chlorination are quite evident, more research needs to be carried out to determine these side effects.”
Source: Hwang BF, Jaakkola JJ, Guo HR.Water disinfection by-products and the risk of specific birth defects: a population-based cross-sectional study in Taiwan. Environ. Health 7(1),23 (2008).
Cigarette smoking in pregnancy may increase the risk of sudden infant death syndrome
Recent evidence proves that there is a causal link between smoking during pregnancy and sudden infant death syndrome (SIDS). This is the first time that the link has been proven, although it has previously been suspected.
In addition, breathing and heart rate regulation disturbances, thermal stress and sleeping in the prone position (with the belly down) can contribute to SIDS.
“Our results provide some of the most direct evidence to date suggesting that prenatal cigarette smoke exposure can contribute to the destabilizing effects of hypoxia and thermal stress on neonatal breathing,” explains Shabih Hasan (University of Calgary, AB, Canada).
The research team exposed pregnant rat pups to cigarette smoke equivalent to that a smoker (who smoked a pack a day) would be exposed to. In addition, they studied a group of control pregnant rat pups who were exposed to room air. Their aim was to observe the compounding effects of cigarette smoking on thermal and oxygen stress, other known risk factors for SIDS.
“Our approach sought to quantify the effects of cigarette smoke holistically, rather than using nicotine exposure as a proxy for cigarette smoke. Nicotine is just one of the 4700 known toxins in cigarette smoke that could have protracted effects on embryonic development and postnatal growth,” explained Hasan.
The rats from the smoke-exposed group and the control group were randomized to either undergo thermoneutral or hyperthermic exposure to an oxygen-depleted environment; their respiratory responses were then analyzed.
Gasping was observed in 13% of the control rats and in 36% of the smoke-exposed rats. In addition, 25% of the smoke-exposed rats exhibited gasping in the thermoneutral environment compared with none of the control rats.
Furthermore, in the hypothermic environment, 29% of the smoke-exposed rats demonstrated gasping behavior, compared with 29% of the control rats. “These results also indicate the adverse effects of low oxygen and thermal stress even in pups which were not exposed to cigarette smoke during pregnancy,” adds Hasan.
It was evident that the smoke-exposed rats were more likely to demonstrate gasping in various environments.
“Our results show that prenatal cigarette smoke exposure compounds the risk by increasing the likelihood of gasp-like respiration and prolonging the time that it takes for neonates to return to normal breathing following hypoxia,” concludes Hasan. “These observations provide important evidence of how prenatal cigarette smoke exposure, hypoxic episodes and hyperthermia might place infants at higher risk for SIDS and further support efforts to foster prenatal smoking cessation programs.”
Source: Pendlebury JD, Wilson RJ, Bano S, Lumb KJ, Schneider JM, Hasan SU. Respiratory control in neonatal rats exposed to prenatal cigarette smoke. Am. J. Respir. Crit. Care Med. 177(11), 1255–1261 (2008).
Half of chromosomal abnormalities may go undetected in prenatal biochemical screening
Prenatal biochemical screening tests identify fewer than half of chromosomal abnormalities in the fetus, it was reported at the annual conference of the European Society of Human Genetics. Francesca Grati, TOMA laboratory, Italy, believes that these findings suggest that women should be made more fully aware of these diagnostic limitations.
A total of 115,576 prenatal diagnoses from the past 14 years were considered in the study. Of these were results from amniocenteses and 30,729 were chorionic villus samplings. These two tests both carry risks of miscarriage and so the pregnant women have to decide whether or not the test is worth performing.
“Since our sample included a large number of women aged less than 35 years who underwent invasive prenatal diagnosis without any pathological indication to do so, we felt that the results could be useful in helping to inform pre-test counseling of such women,” explains Grati. “Up until now, the information we had came from smaller studies which only looked at the performance of these tests in detecting a limited number of chromosomal abnormalities,” she adds.
Researchers combined results from the analysis of chromosomal abnormalities from their own dataset with the official published detection rates from two large multicenter trials. They concluded that currently used screening procedures were capable of detecting only half of chromosomal abnormalities, regardless of age.
It is hoped that these findings will highlight the need to better inform women undergoing prenatal biochemical screening. Grati adds, “Our research confirms that it is fundamental for doctors to counsel patients about the limitations of current screening methods, so that they can make an informed decision on whether or not to undergo invasive diagnostic testing.”
Source: http://news.bbc.co.uk
Mechanism found for cocaine-related brain damage to fetus
If cocaine if used by an expectant mother, the effects on the unborn baby’s brain are specific neurological and behavioral abnormalities, reveals a recent study. The team, who have gained a better understanding of the mechanisms by which cocaine affects the fetal brain, believe that this knowledge could be used to develop a treatment to protect unborn babies whose mothers are unable to cease cocaine use.
Cocaine use in pregnancy affects the CNS of many babies in the USA. The research team, from the NIH, USA, set out to investigate the mechanisms by which cocaine affected the fetal brain.
The team found that a major byproduct of cocaine metabolism affects Cyclin A, a cell signaling substance. The cellular mechanism causing this was found to be due to oxidative stress in the cell’s endoplasmic reticulum, which has an effect on the production of protein.
The team administered the drug cimetidine to pregnant rats as it interacts with the enzymes that metabolize cocaine. They were then able to counteract the neural development inhibition caused by exposure to cocaine. This could result in treatments that block the interaction of cocaine with Cyclin A in pregnant women unable to cease cocaine use to protect the developing fetus. However, more research is required to establish whether this will be effective in humans.
Source: Lee C-T, Chen J, Hayashi T et al.A mechanism responsible for the inhibition of neural progenitor cell proliferation by cocaine. PLoS Med. 5(6), E117 (2008).