Another blog post suggested by a reader, this time from Jim Goodmar from San Diego.
This study of neurological and developmental outcomes of babies born before 25 weeks is remarkable in a number of ways. (Herber-Jonat S, Streiftau S, Knauss E, Voigt F, Flemmer AW, Hummler HD, Schulze A, Bode H: Longterm outcome at age 7-10 years after extreme prematurity-A prospective, two centre cohort study of children born before 25 completed weeks of gestation (1999-2003). The journal of maternal-fetal & neonatal medicine 2013, 0).
Firstly the proportion of infants who survived is outstanding. There were 128 infants born in the 2 centers (Munich and Ulm) over a 5 year period, of whom 107 survived. Some infants at each number of weeks of gestational age had compassionate care from birth, but among those infants at 23 weeks who had pro-active care the survival was 80% to discharge, and 87% at 24 weeks. One interesting point in the description of the patients there were no babies who received pro-active care in the 22 to 23 week group who were growth restricted. It appears (quite reasonably) that birth weight was a factor in deciding whether to start intensive care.
The infants were followed until 7 to 10 years of age, and had a battery of tests performed. The only limitation of this study is the large number of infants lost to follow up. Although it is difficult to follow babies for so long, the generalizability is affected by losing 25%.
The proportion of infants with no impairment is impressive, 76% of the children had either no, or mild impairment. Only 2 of the babies were considered severely impaired, one with severe cerebral palsy, the other blind.
Significantly, there was no difference in long term outcomes between babies born at 22 or 23 weeks, compared to those born at 24 weeks.
The IQ test scores were very similar between groups, being slightly better on all subscales in the more immature group. For example the full scale score in the 22-23 week babies was a mean of 92, with none of them being below 70. It was 86 in the 24 week infants, with 10% being less than 70.
These results have certain specific characteristics, the babies were all inborn in tertiary care centers where a positive attitude prevails, leading to a high prevalence of antenatal steroid use at all the gestational ages represented. Mild impairment included infants with cerebral palsy who were mildly affected with a GMFCS of 1, or with an IQ score between 70 and 84.
These data are entirely consistent with the recent systematic review that I blogged about recently from Greg Moore and colleagues in Ottawa, at early school age among the most immature infants, the proportion of survivors who are impaired does not change with gestational age (and that review included infants of 25 and 26 weeks also). Our antenatal counseling and decisions about pro-active care should be based on survival. Very long term outcomes are not different among extremely immature infants by completed weeks of gestation, if you follow them for long enough. Overall the proportion of impaired infants gets lower as they get older, and the gradients that are visible at 18 to 24 months usually disappear.
If we are to base decision making on long term impairments (and I think that really is an ‘if’ unless we can reliably predict profound impairment), then that requires that we include sepsis, NEC, surgery, BPD, all things that occur after birth. As there is no difference in severe impairment by gestational age, and no effect on quality of life by gestational age, then we should discriminate by survival, which is more related to birth weight at these profoundly low gestational ages than to completed weeks of gestation. Profound impairment is relatively uncommon, and completely unpredictable before birth.