“You’re going to need this,” a harried fellow mother said as she shoved a few graham crackers into my hands as we stood one morning in a crowded Bethesda park. My son was careening around his little sister who was fast asleep in their double stroller. “It’s the only way I can ever get them out of here,” she nodded in the direction of her own frenetic twin boys who were getting perilously close to falling off the monkey bars.

It was my initiation into the world of cluster babies. Because, unlike this kind stranger, I don’t have twins myself, but I might as well. My husband and I waited until our 30s to start our family and we decided we didn’t want to waste any time so we had our second child only 14 months after our first was born.

It’s no secret that women are waiting longer to have children. According to the
CDC’s National Center for Health Statistics, the average age of women in the U.S. who gave birth to their first child was 21.4 years old in 1970. That number shot up to 25 years old in 2006. In 1970 only one out of every 100 first births was to women 35 and over but in 2006 that number was about 1 in 12. Last year, the rate of women between 35 and 39 having their first child was up 3 percent from 2012, its highest rate since 1963. Yet the number of women having babies in their early 20s has plummeted to a record low and the rate of women aged 25 to 29 having their first child has declined every year since 2007.

An unintended consequence of this shift is that some women feel that they can’t afford to wait years between babies. According to the most recent information available from the CDC, the mean age of women at the birth of their first child and their second child is rising, and the gap between deliveries is narrowing.

In 1980 the mean age at first birth was 22.7 years old and 25.4 years old at second birth, resulting in a 2.7 year gap. That gap has stayed fairly constant. But in 2012 the data shows that women of all races were older – 25.8 at first birth and 28.4 at second birth – and there was a 2.6 year gap between children.

It’s people like me who are helping to narrow that gap. If this subtle shift grows (and the anecdotal evidence I’ve collected from the parks and grocery stores in suburban Washington suggests that something is indeed changing), it could lead to significant strain for American parents. Especially American mothers.

As anyone who has ever had a baby knows, the physical labor involved, from feeding to diapering to entertaining, requires a herculean effort and infinite amounts of patience. Now, multiply that by two. Having a second baby so close in age to our first was nothing short of miraculous and we feel so lucky to have two healthy children.

But there is an undeniable added level of intensity that comes with having two babies to care for instead of one. And while having more than one child can be a wonderful thing that helps complete a family, or even leaves parents yearning for baby number three, it can sometimes carry stress that is disproportionately felt by the mother, only compounded by the closeness in siblings’ ages.

According to a study by the Web site FiveThirtyEight, the short-term impact of the birth of a first child was the same for mothers and fathers with 60 percent saying there was a significant change in their level of happiness and half of them saying that they were happier.

However, of the subset of those who said they had a change in their levels of happiness, 40 percent of men and 65 percent of women said they were less happy in the first couple of years after their second child’s birth.

Shortly after our son was born, I made the decision to leave my job as a White House reporter for Bloomberg News. The hours were too long, the travel too frequent, and I just didn’t see how I could spend enough time with him. I recognize that I am incredibly lucky to be able to work part-time from home on a project that I am passionate about with the support of my husband.

And like so many women, I decided that condensing this period of intense motherhood made sense. My husband is an only child and I have a sister who is 1o years younger than me. We both wanted our son to have a brother or sister who is close in age. It just seemed practical to have another baby quickly since we already have plenty of age- appropriate toys, our house is pre-childproofed, and neither of us was getting any younger. (I was 33 and he was 35 when our second child was born.)

There was also something selfish about the decision. I told everyone who offered pitying glances when I was carrying my thirteen-month-old on my hip while I was eight months pregnant: “We just wanted to get it over with.” But in reality I also desperately wanted to have my body back – to exercise more intensely, to eat sushi, to have a glass of wine from time to time.

When I was pregnant with our second child my husband and I rarely worried about the backbreaking exhaustion that accompanies having multiple children still in diapers. We were thrilled to have our baby girl and I’m still amazed when I look into my children’s eyes. But since then I’ve been reading up on it (during the rare 10 minute interval when my son’s all-too-brief nap overlaps with my daughter’s nap), and these trials and tribulations have been well documented. In fact, author Sybil Hart writes in her book “Preventing Sibling Rivalry: Six Strategies to Build a Jealousy-Free Home,” that the “early hardship of caring for two young children can help draw fathers into the action. The tasks are so demanding that even the most alienated and reluctant father would have to step in.”

While my husband is a far cry from “reluctant,” having delved into fatherhood with incredible enthusiasm and remarkable ease, we still joke that the minute he steps into the house after work, he’s joined the chain gang. Diapers must be changed, dinner must be cooked, and a whining dog must be let out.

I think that delaying motherhood for women who have spent their 20s building their careers is a smart choice — and often not a choice at all because of economic conditions. It’s a decision I made myself and one that I don’t regret for a single second.

But in reality, just like everything else about women’s life choices, it’s complicated. I believe that the benefit of having more life experience far outweighs the perils and near total exhaustion of trying to build a family in your 30s and 40s. Besides, it’s never easy, no matter when you decide to have children.

As we left the park that day, I exchanged a knowing look with the thoughtful mother who offered me the graham crackers and who was now using what was left of her supply to coax her twins off the monkey bars.

For now, we should appreciate the moments when a simple snack can make everything better.

Kate Andersen Brower is the author of a forthcoming book about the White House, to be published in April. She covered the Obama administration for Bloomberg News and Businessweek and is the mother of cluster kids Graham and Charlotte. You can follow her @KateBrower.

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