Which fertilized eggs will become healthy human fetuses? Researchers predict with 93% accuracy

Because the parameters measured by the researchers in this study occur before any embryonic genes are expressed, the results indicate that embryos are likely predestined for survival or death before even the first cell division.

.. Despite their best efforts, though, they have only about a 35 percent success rate. As a result, most women elect to transfer two or more embryos to increase the chance of a live birth.

.. the embryos at first express only genes from the maternally derived egg. By roughly the third day (the eight-cell stage) they begin to express genes specific to embryonic development

..  The researchers found embryos in which some cells were dividing on schedule while others were seemingly stuck, or paused.

..  embryos in which individual cells varied significantly in their cell-division schedules or gene-expression profiles were less likely to become successful blastocysts.

.. Cells that fail to execute some part of this delicate process get out of sync with their neighbors and jeopardize the life of the embryo.

.. “In mice, about 80 to 90 percent of embryos develop to the blastocyst stage. In humans, it’s about 30 percent,” said Reijo Pera.

.. “In addition, about one in 100 mouse embryos are chromosomally abnormal, versus about seven out of 10 human embryos.

 

 

What Pregnant Athletes Can Achieve

She told me recently that she ran a ten-miler the day before her daughter was born. “There were definitely people who gave me second glances at the gym,” Brown said. “They said, ‘Are you sure you should do that?’ ” She continued, “I was amazed how during my pregnancy my body knew what to do. I kept thinking how women are strong, how we’re built to be able to have kids, but also be built to do so much more. It’s not that long ago that people thought a woman’s uterus would fall out if she ran too far.”

.. he’s heard stories of athletes in former Soviet countries who, during the Cold War heyday of sports, would intentionally get pregnant, hoping to capitalize on an increased count of red blood cells, and then abort the pregnancies after competing. “It was almost like a natural blood doping,”

Happy Miscarriages: An Emotional History of Pregnancy Loss

Recent studies instead put miscarriage prevalence at 15-20%, and scientists agree that the most common cause of miscarriage is aneuploidy, the presence of an abnormal number of chromosomes. The research team behind the Obstetrics and Gynecology article speculates that the high numbers who felt guilty and ashamed perhaps stem from the culture of silence surrounding miscarriage. After all, if you believe miscarriage to be rare, and have never heard anyone else admit to the experience, it might be easier to believe it is your fault when you have one

.. As contraception and abortion became legal, safe, effective, and affordable for more American women in the latter half of the twentieth century, and scientists untangled the physiology of pregnancy to better understand how it happens and how to avoid it, many women came to feel that they had absolute control over when they got pregnant. That sense of control only increased with advances in artificial insemination, leading many Americans to believe that modern medicine can fix any reproductive problem. But with great control always comes great responsibility. Because they do have such unprecedented control over their fertility, how many women now feel that, when something goes wrong, it must be their fault?