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What Happened?
ABOUT A YEAR and a half after Miraâs birth, when she finally started sleeping through the night, I started to emerge from the deep, consuming fog of anxiety that had enveloped me through her babyhood. After she was born, I was engaged in a balancing act of survival, so afraid to look down that I took in only as much information as was offered.
As I started to come back to myself, to the new landscape that was our family, I had a question: What happened? For us, as for many families, there is no answer to that question. No one knows why the placenta failed; the lab tests were inconclusive. No one can tell me why Mira had to come into the world the way that she did. Or, for that matter, why I did, too.
So I started to ask the same question in a bigger sense: What happens? What happens to one in ten babies and their families?
When I first heard Mira might come a little early, my conception of preterm birth was ⌠well, embryonic, even though I had known the basic gist of my own early arrival all my life. As I peered back into my memories of her first months, this subject opened itself up in strange and profound and confusing ways. More questions suggested themselves: the weird intersections that had fluttered by, the science I had half understood, the other families that we had passed in that fog. The astounding fact that babies like Mira are now more than likely to survive. What happened?
IF YOUâVE BEEN pregnant, you probably know the prenatal visit drill, and it goes something like this: risk of Down syndrome, diet and weight gain, Pitocin and epidurals and C-sections, genetic testing. There are certain topics that come up over and over in routine obstetric visits. Preterm birth is usually not one of them.
I remember, in particular, how much emphasis was put on finding out if my fetus had Down syndrome, since I was going to be thirty-five when I gave birth, putting me over the line into âgeriatric.â But as a healthy, nonsmoking, thirty-five-year-old, middle-income white woman living in Kings County, New York, I had about an 8 percent chance of a preterm birth. In other words, even without the extra risk indicated by the low PAPP-A, I was already 29 times more likely to give birth early than I was to have a baby with Down syndrome. Chromosomal conditions like Down syndrome canât be cured, of course, but once they are discovered, there is a decision to be made: continue the pregnancy or end it. And physicians like to offer medical options; I donât blame them. With preterm birth, this is impossible. There is precious little scientific consensus on why it happens, much less how to prevent it. In many cases, there is nothing much to do but wait, watch, and hope to go full term. It is a phenomenon defined by uncertainty. And to complicate matters further, it is a pregnancy outcome with many different causes, not a single disease or condition. Any true statement about prematurity has at least a dozen caveats.
ONE OF THE most astonishing facts about preterm birth is just how common it is, how devastating it is to the health of women and babies, and yet how invisible. Premature birth is the leading cause of newborn death in the United States and worldwide. It has surpassed pneumonia as the leading cause of death for children under five throughout the world. It is also a leading cause of developmental problems of all kinds, learning disabilities, and chronic conditions like asthma.
Prematurity costs the United States about $26 billion per year, and, more importantly, it is the cause of untold sorrow and struggle. The American preterm birth rate is 10.02 percent and rising; thatâs almost 400,000 premature babies each yearâthe worst rate in the industrialized world. Worldwide, 15 million babies are born too soon, and about 1 million of them die as a result.
The consequences of a preterm birth can follow even the luckiest of families for years, sometimes for entire lives. It is a postpartum anxiety or depression that is too slow to ebb, a lingering vigilance, an alarm that keeps ringing in your head. It is dragging an oxygen tank with you to the playground. It is carting a baby, then a toddler, then a preschooler, to physical and occupational therapists and learning specialists and pediatric pulmonologists and neurologists. And yet, experiencing premature birth can also forge a sense of wonder, gratitude, and strength.
WHEN MIRA WAS in the NICU, I was terrified. When she got home and I found out that she needed physical therapy for a motor delay, I was overwhelmed by the very notion of navigating the Early Intervention System and angry that I had to think about it. When she had her first asthma attackâa common complication of prematurityâI held the nebulizing mask to her face, felt her little rib cage contracting with each labored breath, and wanted to scream.
But also, being her mother is the greatest joy of my life. When she was a baby, I couldnât get enough of the way she kick-kick-kicked her little legs when she was delighted, the hugeness of her grin, the grave look on her face when she studied a stuffed animal. As she grew, she became physically fearless, rough-and-tumble, a tiny, delicate-looking child who was anything but delicate. She is sharp, inquisitive, funny, and thoughtful. She is formidable. She has amazed me from the moment she was born.
For the richest country in the world, the United Statesâ preterm birth rate is clearly too high, and so is its sad corollary, infant mortality. The fact that we do have such a high rate, and that itâs even higher for black women and other marginalized communities, is an indictment. Cynthia Pellegrini, a senior vice president for public policy and government affairs at the March of Dimes, compares preterm birth rates to the canary in the coal mine. âIf those numbers are going up,â she said, âit means that something is wrong.â And the numbers are going up. For a resourceful, rich country that claims to value families, having a child is fraught with avoidable suffering and risk.
However, as always, statistics donât tell the whole story. Sometimes an early birth is the best possible outcome: In the absence of other treatments, it might be necessary to avoid the risk of stillbirth, as it was for Mira. So a rise in preterm birth can also mean a decrease in stillbirths. Or an early delivery might be necessary to protect a motherâs life, for instance, when she has preeclampsia. At a March of Dimes conference that I attended in 2018, a physician made this key point: For a patient who has given birth previously at, say, 26 weeks, a second pregnancy lasting 35 weeks is a triumph even though itâs still classified as a preterm birth. Conversely, if a woman presents with preeclampsia at 36 weeks, delaying delivery long enough to push her over the term line to 37 weeks at the expense of her or her babyâs health is not a successâalthough it might look like one statistically.
IT HELPS TO understand the basics. A typical healthy pregnancy lasts between 37 and 42 weeks. Any birth before 37 weeks is premature, or preterm. Gestational age is simply the number of weeks since the start of the pregnant personâs last period; most people conceive around week 2. Preterm babies continue to go by gestational age, even outside the womb, until they hit 40 weeks. In other words, when Mira was one month old, she could have been called a 28-week baby who was now 32 weeksâ gestational age.
Broadly, there are two kinds of preterm births: those that are the result of spontaneous preterm labor or rupture of membranes (water breaking)âwhich account for about two-thirds of all preterm babiesâand medically induced early deliveries (either C-section or vaginal), which make up the remainder. When providers decide to induce a premature birth, it is because something has gone wrong, and birth is necessary to protect the babyâs life, the motherâs life, or both.
There are lots of different causes for both kinds of preterm birth, but many preterm births donât have a known medical explanation. When parents ask, What happened? the only answer is, We donât know.
However, there are some established risk factors: High blood pressure, either previously existing or pregnancy related, can lead to one of the most common causes of premature birth, preeclampsia. This is a condition that causes damage to maternal organs like the liver and kidneys, and it can escalate into a life-threatening syndrome if left untreated. Preeclampsia often necessitates delivery to protect both the mother and baby.
Placental problems, like a placenta that stops working unexpectedly, as mine did, or one that abrupts (partially separates from the uterine wall) or is attached to the cervix (placenta previa), can lead to premature labor or to a medically indicated premature birth. It can also happen because of a cervix that wonât stay closed, or an irregularly shaped uterus.
Infections, like those of the urinary tract or the amniotic fluid and membranes, can trigger premature labor, especially when they go untreated.
Women pregnant with multiples are more likely to give birth early, as are women who used in vitro fertilization (IVF) to get pregnant and women younger than twenty or older than forty. Being underweight or obese is associated with premature birth, as are behaviors like cigarette smoking. Exposure to clinically significant chronic stress, like income insecurity, racial discrimination, unsafe working conditions, and trauma, also puts women at higher risk of giving birth early.
Having pregnancies that are spaced closely together increases risk for preterm birth; experts advise getting pregnant again no sooner than eighteen months after giving birth. (After a first-trimester miscarriage or abortion, there is apparently no medical need to wait longer than one cycle to get pregnant again.) That means that access to family planning and contraception is a meaningful intervention against premature birth.
And people who have given birth early before are much more likely to give birth early again. The good news is that increased monitoring can help; your provider might suggest weekly progesterone shots if youâve had unexplained early labor in the past, or low-dose aspirin if you have high blood pressure.
But there has not been as much progress toward the prediction and prevention of premature birth as there has been on the neonatal side, caring for preemies. At the moment, progesterone and low-dose aspirin are really the only two drugs available to stave off premature birth, and their effectiveness is limited. But a recent groundbreaking study from the University of California, San Francisco, used a blood test early in pregnancy to measure certain proteins and biomarkers. By evaluating the test results along with information like maternal age and income, researchers were able to predict whether a pregnant individual would go on to have a preterm birth with 80 percent or better accuracy. This would be extremely good to knowâincreased monitoring can improve outcomes significantlyâbut there would still be no sure way to stop it from happening altogether. At least, not yet.
Once labor starts in earnest, there are medications called tocolytics to slow or stop labor and delay birth.
These are mostly temporary measures, but a delay can be lifesaving, because one of the most important advances of the last several decades has been the use of corticosteroids, which became standard practice in 1994. When obstetricians think a baby might be born before 34 weeks, they give the mother a series of two of these steroid shots, twenty-four hours apart. The steroids rev up the fetusâs lung development, which is one of the last systems to mature. This treatment makes a huge difference in both survival and in long-term health outcomes, but it needs at least twenty-four hours to take effect.
Once a baby is born early, the severity of their immaturity is categorized by gestational age. Extremely preterm is fewer than 28 weeks; very preterm is fewer than 32 weeks; moderately preterm is fewer than 34 weeks; and late preterm is fewer than 37 weeks.
Some providers have proposed a separate category: Babies born at 25 weeks or younger are sometimes called profoundly or severely preterm, or âperiviable,â for the way they straddle the viability zone.
Birth weight is divided into similar categories: Extremely low birth weight is under 1,000 grams (2.2 pounds); very low birth weight is under 1,500 grams (3.3 pounds); low birth weight is under 2,500 grams (5.5 pounds).
Often the immaturity and weight categories track together: extremely preterm babies are usually extremely low-birth-weight babies. And those categories are sometimes lumped together in studiesâfor example, a study might include outcomes for both extremely premature babies and babies under 1,000 grams. (Birth weight is a more precise measurement than gestational age.) But because some babies are growth restricted, or small for gestational age, or the opposite, the groups are not always equivalents. Mira, for example, was very preterm but extremely low birth weight. She was more mature than her birth weight would suggest.
A neonatal intensive care unit is a special nursery where very premature and critically sick babies can get all the medical care they need, including incubation, life support, and sometimes surgery. Premature babies are not the only babies who need NICU careâterm babies can have complications, disorders, and illnessesâbut generally premature babies make up the majority of NICU patients.
