When I was growing up in the 1970s, I did not know a single twin. My kids’ school, on the other hand, is crawling with them. And that, increasingly, is the norm across the country. Julia Roberts and Marcia Cross are the tip of a very big iceberg – the biggest twins boom in American history.
In 2004, the most recent year for which government statistics are available, more twins – 132,000 – were born in the United States than ever before. And in cities, where women are more likely to wait until later to have babies and use fertility methods to conceive, the rate is even higher. The older the mother, the more likely she is to ovulate more than one egg at a time, and in vitro fertilization and fertility drugs increase the odds of a multiple birth. Recent studies have also suggested that factors such as folic acid, obesity and dairy products may be fueling the increase in twins.
Whatever the cause, twins have become normalized. Under ordinary conditions – which is to say, conditions that have prevailed through all of human history until this point – one out of every eighty births is a twin, but in this country, that number has risen to the point where one out of every thirty-three children born is a twin. Which means you probably either have twins yourself, or see them out in force on the sidewalks and at the playground.
But just because they’re far more common than they used to be, doesn’t mean twins have become any easier to deliver, or to raise. A twins pregnancy is riskier than many realize. Babies born as twins are hospitalized twice as long as singletons, and their medical costs are three times as high over the first five years. Among twins, infant mortality rates are six times higher than that of singletons. On average, fifty percent of twins arrive premature, making them more susceptible to long-term problems such as developmental delays, vision disorders and cerebral palsy.
And there are risks to the mother. For a woman pregnant with twins, the risk of postpartum hemorrhage and postpartum infection doubles, from 4.7 percent to 9 percent. The risk of needing a blood transfusion or hysterectomy doubles. The risk of preeclampsia jumps from 4.4 percent to 10.3 percent, and the onset occurs earlier. “The human uterus was not made to carry more than ten pounds,” estimates Mark Evans, a doctor who specializes in high-risk pregnancies. (The average twin weighs about 5 ½ pounds.)
And once the babies come home, the logistics become staggering. In some ways, what twins there were must have been easier for mothers to manage back in the 1960s, when it was socially permissible to stick them in the back seat and let them wallow on the vinyl seats untethered, and when there wasn’t so much pressure to breastfeed, co-sleep and sling-carry. The rise in twins births has coincided with an obsessive, somewhat misleading emphasis on the importance of the first three years, during which, parents are told, they must do everything possible to achieve that all-important goal: attachment. And they still have to get the babies from one place to another.
It’s easy to see why twins-specific baby products – like the Maximom, a double-carrier that allows a parent to carry two babies at once, like a milkmaid, or a yoked mule – are booming. In 2003, Baby Trend came out with a twins version of its popular Snap-N-Go, a lightweight frame onto which two car seats can be clipped, turning it into an instant, easily assembled twin stroller. “We had so many consumers looking for it,” said Chip Whalen, the general manager at Baby Trends; he estimated that twins parents make up about ten percent of his company’s business. Needless to say, products catering to twins are becoming widespread. In addition to double strollers, there are coordinated clothing lines, as well as lines of extra tiny infant outfits, with cutesy names like “Preemi-Yums.”
The rise in twins has made urban preschools more competitive than ever. “I got up at five o’clock in the morning,” said Rachel Haas, a mother of twins, of her efforts to get her children enrolled. Her neighborhood preschool, like most preschools in the D.C. area, is hopelessly oversubscribed. Parents wait in line to register, and some camp out the night before. “There were people, I am not kidding, there were people in the parking lot at five o’clock the Friday before the Saturday that it opened at eight. They slept in their cars.”
The twins boom isn’t likely to abate any time soon; the rate of first birth for women continues to rise every year, meaning that older mothers aren’t going away. And while IVF doctors are limiting the number of embryos they implant in order to reduce the number of triplets (whose rates have also soared), many doctors see twins as a “reasonably acceptable complication.” In some European countries, a strong government push toward single-embryo transfer means that IVF twins rates in these countries are lower. But here, where IVF patients are footing the bill themselves, many actively hope for twins.
The upshot will be continued adjustment; in my own children’s suburban public school, twins are so common that when my son was in the first grade, there were two twin boys in his class. These boys weren’t twins with each other; their respective twins were in other classes. When birthday party time rolled around, I wondered what to do about his twin classmates: invite them alone, or their brothers as well? I asked around, and was told that one family brought both twins to a party even if the other wasn’t invited, explaining, “it’s too difficult to break them up.” But when I asked the mother of the other set of twins if she would also like both her boys invited, she replied that the child in my son’s class was grateful – finally – to be invited to a party of his very own.