A common early complication of preterm birth is happening later

Key takeaways:

• Half of intraventricular hemorrhages occurred within the first 48 hours of life after 2007, compared with 82% before.
• Researchers believe the delay in onset is due to improvements in neonatal care.

The prevalence of intraventricular hemorrhage among preterm infants has not changed over time, but it occurs later in life than it did 20 to 30 years ago, according to the results of a large study published in JAMA Pediatrics.

The researchers suggested that improvements in care for preterm infants in the last 15 years — including more consistent use of antenatal steroids, magnesium sulfate, thermal protection and delayed and physiological-based cord clamping — have made it possible to postpone but not eliminate intraventricular hemorrhage (IVH).

“Intraventricular hemorrhage is a common and the most significant early complication responsible for adverse outcomes in very preterm infants,” Zsuzsanna Nagy, MD, from the department of obstetrics and gynecology at Semmelweis University in Budapest, Hungary, and colleagues wrote. “Improvements in neonatal care may reduce the risk of both mortality and IVH.

“When the effectiveness of these interventions is assessed, it is essential to know when IVH occurs,” they wrote.

Nagy and colleagues conducted a systematic review and meta-analysis of 64 studies of 9,633 preterm infants to calculate the prevalence of IVH at different time points within the first 3 days of life. They also looked for trends in IVH onset from 1981 to 2006 and from 2007 to 2023 to see if changes in neonatal care affected onset.

Overall, 33% (95% CI, 29%-37%) of infants experienced IVH and 10% (95% CI, 8%-13%) experienced severe IVH, the researchers wrote. They did not find a significant difference in overall prevalence of IVH or severe IVH before or after 2007.

There was no significant difference in IVH prevalence based on gestational age before 2007, but Nagy and colleagues noted that IVH occurred more frequently in infants younger than 28 weeks’ gestational age vs. infants younger than 32 weeks’ gestational age (41%; 95% CI, 31%-52%; vs. 27%; 95% CI, 20%-36%, respectively). Compared with infants born at 32 weeks’ gestational age or less, severe IVH was also more common among infants younger than 28 weeks gestational age before and after 2007 (7% vs. 18 %, and 8% vs. 17%, respectively).

"This finding is consistent with the expectations that the risk of severe IVH is inversely associated with gestational age,” Nagy and colleagues wrote.

The proportion of very early IVH events that occurred within the first 6 hours of life fell from 35% (95% CI, 24%-48%) before 2007 to 9% (3%-23%) after. Additionally, the proportion of IVH events occurring within 48 hours of birth decreased from 82% (95% CI, 65%-92%) before 2007 to 50% (95% CI, 34%-66%) after 2007.

“Although the occurrence of IVH in preterm infants did not change over time, the time of onset of IVH shifted toward later in life,” the researchers wrote. “These data suggest that recently implemented preventive measures have the potential to postpone rather than reduce IVH in very preterm infants.”