Clinical Updates on Management & Outcomes of Extreme Preterm Birth

Recently, Dr Andrei S Morgan and his team provided a broad overview of extreme preterm birth epidemiology, recent changes, and best practices in obstetric and neonatal management. They explored short and long term medical, psychological, and experiential consequences for individuals born extremely preterm, their mothers and families, as well as preventive measures that may reduce the incidence of extreme preterm birth. The updates were published in the BMJ on January 10, 2022.

Based on gestational age World Health Organization (WHO) categorizes preterm into the following 4 criteria:

• Preterm is defined as birth at less than 37 weeks or 259 days' gestation
• Moderate to late preterm is defined as birth at 32-36 completed weeks of gestation
• Very Preterm is defined as birth before 32 completed weeks of gestation
• Extremely preterm is defined as birth before 28 completed weeks of gestation (up to and including 27 weeks and 6 days of gestation)

Based on birth weight WHO defines preterm by:

• Low birth weight as birth weight of less than 2500 g
• Very low birth weight as birth weight of less than 1500 g
• Extremely low birth weight as birth weight of less than 1000 g

Perinatal survival has improved in recent years. The panel noted that extreme preterm birth has been stable in high-income countries over the past 25 years. However, they observed variability between countries and noted that the variabilities are due to differences in the definition of stillbirth and recording of data.

Regarding stillbirth, the panel wrote, "No agreed international definition of stillbirth exists, and the recording of fetal deaths at extreme preterm gestations varies by country. European recommendations are that all births from 22 weeks' gestational age should be officially recorded, but some countries define stillbirth using higher thresholds or birth weight. For example, stillbirth is defined as fetal death from 24 weeks in the UK and by the World Health Organization, 180 days in Italy, and 28 weeks in Bulgaria; in Austria, Belgium, Czech Republic, Germany, and Poland, fetal deaths are recorded at 500 g and above."

With regards to long term morbidity, the panel noted that higher intensities of perinatal and neonatal care are related to improved survival. They also addressed that limitation in the evidence for improvements in longer-term neurodevelopmental outcomes. They noted variability in the provision of care for extreme preterm birth has an impact on morbidity and mortality outcomes.