(Flickr / Rolf Venema)
Women in the US are having children later in life than ever before.
The average age of a mother giving birth to her first child was 26 in 2013 — a record high, according to Centers for Disease Control and Prevention data, that includes plenty of women over 35 and even some over 40.
Dr. Norbert Gleicher, founder, medical director, and chief scientist of the Center for Human Reproduction fertility clinic in New York City, thinks this is a trend that is only going to continue. He predicts that advances in the field of reproductive technology will enable older and older women to give birth to their own biological children.
"We will reach a threshold where age no longer matters and women will be able to conceive probably pretty much independent of their age," Gleicher told Business Insider.
It will take serious research to get to that threshold, but Gleicher identified three "revolutionary steps" that scientists are already working on to get us there:
1. Generating mature eggs in a lab
A woman's age-related decline in fertility has been linked to a gradual decrease in the number and quality of cells that can mature into eggs in the ovaries (known as ovarian reserve), notes a report from the ASRM and American College of Obsetricians and Gynecologists (ACOG). Those cells that can become eggs are surrounded with other cells that take care of them and help them grow. The whole complex is called a follicle, and women are born with about a million of them.
Only a tiny fraction of follicles actually mature into eggs that could be fertilized, however. The majority are lost through a process called atresia.
But it could be possible, Gleicher suggested, to take a little bit of the ovary tissue with immature follicles and coax them to mature into eggs in the lab. Scientists have already done this in mice, and the eggs have yielded live babies after in vitro fertilization and implantation in mothers. Research is ongoing to get this to work in humans.
If scientists can manage this, doctors could save thousands of a woman's eggs for future use, many more than egg freezing can — and without the hormone treatment.
2. Growing sperm and egg cells from regular cells
Another way to get more eggs than a woman's body makes available naturally is to make them from normal body cells, called somatic cells. This can be done by first converting somatic cells into stem cells that can become many different types of cells in the body (known as induced pluripotent stem cells), then into egg cells.
Animal sperm and egg cells made this way have resulted in viable offspring, and scientists have succeeded in making human sperm from induced pluripotent stem cells. There are still significant questions about the safety and efficacy of this process, but Gleicher thinks making human eggs and sperm from somatic cells is an achievable goal in the next 10 years.
3. Editing human embryos
(Nishimasu et al, 2014) A key problem for older women trying to conceive is that their older eggs and the fertilized embryos that result are more likely to have genetic abnormalities that will prevent them from growing into healthy babies.
Right now that means older women have slimmer chances of having a baby through in vitro fertilization than young women do, and the babies older mothers do have are more likely to have certain genetic problems.
But with recent news that scientists in China have edited the genes of human embryos — albeit with many ethical questions and technical glitches — Gleicher said it could be possible to fix genetic abnormalities in the embryos of older women. Those embryos would then be more likely to survive, and a major obstacle for older women trying to get pregnant would be treatable.
'Society better get ready'
Gleicher stresses that medicine is "evolutionary," meaning progress happens slowly. Predicting the timeline for the future of medical advances is always tricky, but he predicted these technical issues for older women trying to conceive will be resolved in the next 10 years. It could take another 10 years after that for the technological advances to be adapted into treatments women can actually benefit from, he said.
If we get to the point Gleicher anticipates when age isn't the limitation on women's fertility it's always been, he and colleagues wrote in a recent paper, "medicine and society better get ready for this revolution."
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