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The "Older Mom" Is Nothing New.

When a close friend was trying for a second child in her late 30s, her husband mentioned that all the mothers he saw at the playground seemed old enough to be grandmas. Naturally, she was stung… but not surprised.

Her experience is all too familiar. Our society tends to view older-age parenting–well, really older motherhood–as a new and vaguely menacing trend. We mums of “advanced maternal age” (i.e., over 35) face lots of criticism for our life choices, as potentially harmful for our children and even for society at large.

This view is not only unfair, it’s inaccurate.

Older motherhood is not an anomaly. It is not a terrible departure from the natural, desired state of affairs. In fact, women bearing children in their late 30s and early 40s represents a return to what was once the norm in pre-industrial times, and giving birth later in life has many benefits for women and their children.

Our frame of reference for what we consider the “normal” age for having kids is actually a historical blip.

Consider this fairly typical example of how we discuss “older motherhood”:

“Women now have their first child five years later on average than they did 47 years ago. The average age of first-time motherhood in England and Wales is 28.6, up from 23.5 in 1970.”

If you read enough older motherhood articles, you will notice an odd fact: Nearly all articles compare current birth rates with rates in the 1970s.

Why would the 1970s represent the norm for birth rates? 

Short answer: the CDC.

The 1970s is earliest decade the CDC references in their annual reports on birth rates.


Why would the 1970’s, the decade when the pill became widely available and the women’s movement began to find its footing, be seen as natural or normative for birth rates?
Short answer: the CDC and NHS.


Yet in every other way, the era of bell bottoms and drab brown interiors was abnormal. The Pill became widely available. The first wave of feminism transformed employment opportunities for women. And women began demanding more from their circumscribed lives– politically, professionally, and personally. Using this era as a frame of reference therefore provides a highly skewed picture of motherhood.

To figure out the “normal” age for having babies, we need to peer much further into the past. 


Without birth control or family planning, at what ages did women have babies?

Demographers use the 17th, 18th, and 19th centuries to determine what happens in so-called “natural fertility” populations, which lack access to birth control and family planning.

Among these are French and German villages from the 1700s on, early Canadian and U.S. settler populations from 1650 to the late 1800s, the Sami, a traditional people who lived in the northern parts of Scandinavia from the 1600s to 1800s; and Mormons living in Utah in the 1800s and early 1900s.

In all these populations, the average age at last birth ranges from 39 to 42. The conception leading to a woman’s last successful pregnancy tended to occur between 38 and 41. Advanced maternal age is not an aberration; it is the norm.


Do historical data answer the question: When is it too late to start a family?

We can’t say for certain.

Women in these populations lacked access to medical care and were more vulnerable to malnutrition and infectious diseases than modern women. Their poorer overall health could have impaired their fertility, especially as they aged.

However, the age at which women had their last child in disparate natural fertility populations (which span centuries and continents) is remarkably consistent. It fits well with studies on modern women undergoing IVF. IVF data show a steep decline in fertility beginning in women’s early 40s.

It also fits well with the little data we have on natural fertility among women today. One recent carefully designed study in Denmark of women ages 20-40 is particularly notable.

Danish researchers recruited women who had just begun trying to conceive, to prevent obtaining a sample biased towards infertility. Women in their early 30s and those in their twenties had an equal chance of becoming pregnant.  Women in their late thirties had slightly diminished chances, with about 77% of the fertility potential of women in their mid to late 20s; This mainly affected how long they took to become pregnant. Fertility potential dropped to 50% by the early 40s.


Since the early 1800s, women worldwide have begun having fewer children, largely by ending their childbearing at younger ages.  

Many savvy, professional women assume historical birth data is overly dire. Jean Twenge’s viral 2013 Atlantic article fed into this view, noting:

“The widely cited statistic that one in three women ages 35 to 39 will not be pregnant after a year of trying, for instance, is based on an article published in 2004 in the journal Human Reproduction. Rarely mentioned is the source of the data: French birth records from 1670 to 1830. The chance of remaining childless—30 percent—was also calculated based on historical populations.”

Yet, the key word in Twenge’s statement is not historical but French.

France is where the pattern of smaller family sizes first appears. Sometime in the late 1700s or the early 1800s, married couples in France start to show signs of limiting their broods.

This trend slowly radiates throughout Western Europe. By the mid-1800s, it has hopped across The Pond, and family size in the U.S. and Canada plummets. Women go from bearing over an average of 5 children to fewer than 3.

advanced maternal and older mom birth rate across the globe

birth rate data visualization:

This drop in family size is unrelated to biological fertility. Rather it signals a single behavioral shift: Women begin ending childbearing at younger ages. From the early 1800s to the mid-1900s, the average age at last birth in Europe, the U.S., and Canada drops from 40-42 to 36-38. 

Fast-forward to the 1970s, with the advent of the pill, wider awareness of family planning techniques, and greater educational attainment among women, and this worldwide trend accelerates. 


Women of advanced maternal age having babies is normal. But there is something new under the sun, and that is the drop in younger women having babies.

In the U.S., the average age at first birth has slowly crept up from 21.4 years old in 1970 to 26.3 in 2017.

The teen birth rate alone drives much of this shift. It has declined by a whopping 70% since its peak in 1991. The drop has occurred for all racial and ethnic groups.


advanced maternal age birth rates and drop in teenage pregnancy


It’s hard to argue that the drop is a bad thing. Teenage births perpetuate a vicious cycle of poverty. Children of teenage mothers are more likely to suffer abuse or neglect, enter the foster care system, end up in prison, become teenage parents themselves, and are far less likely to finish high school.


Most women of advanced maternal age have healthy, successful pregnancies. And having babies later in life has major benefits.


Conversely, despite all the hubbub over older motherhood, being born to an older mom is often beneficial.

So while older motherhood does carry some risks, like a substantially higher chance of having an unplanned C-section, most women labeled as advanced maternal age have healthy pregnancies, especially if they begin pregnancy in good health and seek prompt prenatal care.

Plus delaying childbirth substantially boosts women’s earning power. Women who give birth in their late 30s and early 40s also tend to live longer, and their children–for a variety of reasons–score higher on tests of cognitive ability than children born to women in their twenties. Many older women report feeling more emotionally and financially prepared for parenting.

Considering all these benefits, society should drop the snarky criticism and instead sing our praises!

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About Amy

Amy Kiefer is a researcher by training, and earned her Ph.D. from the University of Michigan. She currently lives in the Bay Area with her husband and three children where she writes about fertility, pregnancy, and breastfeeding. Check out her blog,, for more great evidence-based pregnancy and parenting info.


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