The age of first motherhood in the United States is rising, according to available data from the Centers for Disease Control and Prevention. And as women are having kids later, an abundance of research aimed at documenting the facts about fertility is there to terrify, console and perplex them.
Much of the data on what aging means for making babies is anything but hard and fast: Studies contradict studies; anecdotal evidence refutes other anecdotal evidence. It's a trend that Jean Twenge noted in a recent piece for the Atlantic in which she tried to answer the question "How long can you wait to have a baby?"
But as Twenge discovered through her reporting, available research is limited and outdated, despite what an avalanche of magazine features say: "While the data on natural fertility among modern women are proliferating, they are still sparse. Collectively, the three modern studies [on fertility] included only about 400 women 35 or older, and they might not be representative of all such women trying to conceive."
As Twenge notes, many experts agree that while there are documented trends, fertility in general is a bit of a wild card, which seems to be supported by a dizzying array of contradictory information making the rounds. This kind of information overload may also explain why women tend to get so much wrong when answering questions about fertility.
So what does the research say about age and fertility? A lot, in fact. Below, some of the conclusions science has drawn, ranging from least to most reassuring:
Fertility peaks in your 20s, and some studies show it can begin to decline as early as 27
According to the National Center for Biotechnology Information, fertility peaks in your 20s and steadily declines as you age, though the report acknowledges that "the age when fertility starts to decline is different from woman to woman."
Scientists at the National Institute of Environmental Health Sciences in North Carolina and the University of Padua in Italy studied 872 healthy couples. Their research is the first to indicate that female fertility declines before the age of 30. But the doctors said the older women studied were not less able to conceive -- it just took them longer.
Team member Dr David Dunson explained: "Though we noted a decline in fertility in the late 20s, what we found was a decrease in the probability of becoming pregnant per menstrual cycle, not in the probability of eventually achieving a pregnancy."
Fertility rates take a dive at 30, and getting pregnant can become a challenge soon after
"By the time a woman hits 30, nearly all of her ovarian eggs are gone for good" writes ABC News in an article about a study conducted by the University of St. Andrews and Edinburgh University in which researchers found women have "lost 90 percent of their eggs" by the time they reach 30:
The study was based on information collected from 325 women of varying ages in the United Kingdom, the United States and Europe.
Dr. Marie Savard, "Good Morning America" medical contributor, visited "GMA" to discuss the issue and its implications for moms-to-be.
"Women lose eggs a lot faster than we thought," she said. As you get older, conceiving is "much more difficult. ...Even all those assisted reproductive techniques are challenges."
"That biological clock does tick," she said, adding that her advice to women who want kids is, "the sooner the better."
Fertility is pretty stable until you hit your late 30s, but things may get dicey after that
As Twenge reports in the Atlantic, doomsday scenarios about fertility after 30 may be vastly overstated:
Surprisingly few well-designed studies of female age and natural fertility include women born in the 20th century — but those that do tend to paint a more optimistic picture. One study, published in Obstetrics & Gynecology in 2004 and headed by David Dunson (now of Duke University), examined the chances of pregnancy among 770 European women. It found that with sex at least twice a week, 82 percent of 35-to-39-year-old women conceive within a year, compared with 86 percent of 27-to-34-year-olds. (The fertility of women in their late 20s and early 30s was almost identical — news in and of itself.)
Another study, released this March in Fertility and Sterility and led by Kenneth Rothman of Boston University, followed 2,820 Danish women as they tried to get pregnant. Among women having sex during their fertile times, 78 percent of 35-to-40-year-olds got pregnant within a year, compared with 84 percent of 20-to-34-year-olds. A study headed by Anne Steiner, an associate professor at the University of North Carolina School of Medicine, the results of which were presented in June, found that among 38- and 39-year-olds who had been pregnant before, 80 percent of white women of normal weight got pregnant naturally within six months (although that percentage was lower among other races and among the overweight). “In our data, we’re not seeing huge drops until age 40,” she told me.
Fertility is still an option at 50, but will most likely require medical intervention and there are increased risks
According to a report from the BBC, one study found that women in their 50s were still able to conceive using fertility treatments:
Age alone should not stop women in their 50s from receiving fertility treatment, say doctors. Even post-menopausal women were able to have babies using eggs donated by younger women, according to a US study. Researchers followed the progress of 77 post-menopausal women undergoing IVF treatment using donated eggs at the University of Southern California...
The researchers, led by Dr Richard Paulson, say there is no medical reason why women in their 50s should not have fertility treatment.
"Appropriately screened women aged 50 years or older can successfully conceive via oocyte donation and experience similar pregnancy rates, multiple gestation rates, and spontaneous abortion [natural termination] rates as younger recipients, " they write in the Journal of the American Medical Association.
They do identify some increased risks, however. Women over the age of 50 are more likely to suffer from a disease of pregnancy known as pre-eclampsia. It causes high blood pressure and, in severe cases, can lead to the death of mother or child. Older mothers are also more likely to get diabetes during pregnancy.