Late Preterm Birth - AGAIN

The other night I was preparing a Grand Rounds’ presentation on late preterm birth for the next morning. There was going to be a large group of resident applicants in the audience, and the competition for the cream of the graduating medical school students going into OB/GYN has gotten intense in recent years, so I wanted to make a good impression for our department. But, I could sense the talk was missing something; the inspiration for putting the finishing touches on the talk was also being interrupted by periodic pages to the labor and delivery unit because I was on call that night in the hospital.

At about 11:00 PM, the muse arrived in the form of a phone call. A physician in our perinatal catchments area had been caring for a 26 year old woman who was having her first baby. She was “about 37 weeks” and had told him that “the baby wasn’t moving as much as usual.” To assess fetal well-being, he had done a nonstress test that was “reassuring” and, despite this, had also done a contraction stress test that was “reassuring” as well. When I asked if there was “normal fluid” and if the baby was “normally grown,” the answers to both those questions was “yes” and “there had been no other complications to date in the pregnancy.” Then he told me that the patient “is a nurse on labor and delivery and a friend” and at that point, I knew exactly where the conversation was going…

“Because she was so late in the pregnancy, and she was worried, we went ahead and induced labor anyway.” Since her cervix was very unfavorable for induction, he had used a drug called misoprostol to “ripen the cervix and start the induction.” Her uterine contractions became too frequent on this and he could not be sure that the fetal heart rate pattern was still reassuring, so a cesarean section was performed for the delivery at 3:00 PM that afternoon. Shortly after delivery, the baby developed respiratory difficulties and needed to be transferred to our neonatal intensive care unit (NICU). He was calling now to see if I could accept the woman in transfer so that “she could be with her baby.” After we admitted her at 3:00 AM, I finished off my Grand Rounds preparations by including her ‘case report’ in the presentation.

We have previously discussed that about 13% of all births in the U.S. are preterm (less than 37 weeks’). The major contributor to the continuing rise in PTB over the past two decades has been late preterm births at 34-37 weeks. Indeed, these now comprise approximately 75% of all preterm deliveries, or more than 300,000 babies per year, and more than 75% of these babies come from Hispanic and non-Hispanic white populations. The rise in late PTB has been paralleled by the rise in births to women over 30, the rise in induction rates, and the rise in primary and repeat cesarean deliveries. At least half of all late PTB babies are delivered by cesarean section. Unfortunately, at least half of all late preterm deliveries are ‘iatrogenic,’ resulting from marginal maternal or fetal indications for delivery or inadvertent intervention because of uncertainty related to gestational age.

Although the relative risk for severe neonatal complications is fairly low, the cumulative risk, secondary to the large number of babies, is high. Many of these babies are delivered, intentionally or unintentionally, at Level 1 or Level 2 facilities and start off life in the normal newborn nursery. Under these circumstances, they may not be identified or managed as ‘preterm’ babies and this can result in delayed recognition of neonatal complications such as respiratory distress, hypoglycemia (low blood sugar), hypothermia (low body temperature), and pulmonary hypertension. These conditions result from ‘delay in transition’ from intrauterine to extrauterine life, can be quite serious, and require a higher level of monitoring and support than that available at many local hospitals. Other complications, such as jaundice related to hyperbilirubinemia and feeding problems, may not be recognized until days after discharge from the hospital, but also can have serious consequences. Delayed recognition of any of these problems can result in delayed transfer to a tertiary care center that, by itself, is well known to be correlated with greater risk for neonatal morbidity and mortality.

Late preterm birth means a lot more than the baby having to spend a few extra days in the hospital. Neonatal and infant mortality among these babies is 3- to 4-fold that of their term counterparts. As illustrated in our ‘case report,’ late PTB is associated with higher rates of NICU admission (inborn and by transfer), greater lengths of hospital stay, higher risk for hospital/NICU readmission, and a dramatic increase in health care costs. It is estimated that the average late PTB baby that requires special care adds $20,000 to $60,000 to the expenses expected at term. Although there is not much data at present to tell us the long-term morbidity and lifetime cost resulting from the complications of prematurity related to late PTB, commonsense tells me that these will be quite significant.

After presenting Grand Rounds, I went back to see the subject of our ‘case report.’ Her baby was doing well in the NICU, but she looked at me sheepishly and said, “We didn’t do right, did we?” I tactfully avoided answering the question, directly, because she already knew the answer, but I did take the opportunity to praise our NICU team and to tell her that I thought that “everything would turn out alright……this time.”

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