Trond Markestad

BACKGROUND: Advances in perinatal care have increased the number of premature babies who survive. There are concerns, however, about the ability of these children to cope with the demands of adulthood. METHODS: We linked compulsory national registries in Norway to identify children of different gestational-age categories who were born between 1967 and 1983 and to follow them through 2003 in order to document medical disabilities and outcomes reflecting social performance. RESULTS: The study included 903,402 infants who were born alive and without congenital anomalies (1822 born at 23 to 27 weeks of gestation, 2805 at 28 to 30 weeks, 7424 at 31 to 33 weeks, 32,945 at 34 to 36 weeks, and 858,406 at 37 weeks or later). The proportions of infants who survived and were followed to adult life were 17.8%, 57.3%, 85.7%, 94.6%, and 96.5%, respectively. Among the survivors, the prevalence of having cerebral palsy was 0.1% for those born at term versus 9.1% for those born at 23 to 27 weeks of gestation (relative risk for birth at 23 to 27 weeks of gestation, 78.9; 95% confidence interval [CI], 56.5 to 110.0); the prevalence of having mental retardation, 0.4% versus 4.4% (relative risk, 10.3; 95% CI, 6.2 to 17.2); and the prevalence of receiving a disability pension, 1.7% versus 10.6% (relative risk, 7.5; 95% CI, 5.5 to 10.0). Among those who did not have medical disabilities, the gestational age at birth was associated with the education level attained, income, receipt of Social Security benefits, and the establishment of a family, but not with rates of unemployment or criminal activity. CONCLUSIONS: In this cohort of people in Norway who were born between 1967 and 1983, the risks of medical and social disabilities in adulthood increased with decreasing gestational age at birth.

OBJECTIVE: To determine outcomes, in terms of perinatal and early death, need for treatment, and morbidity at the time of discharge home, among extremely preterm infants. DESIGN: A prospective observational study of all infants with a gestational age (GA) of 22 to 27 completed weeks or a birth weight of 500 to 999 g who were born in Norway in 1999 and 2000. RESULTS: Of 636 births, 174 infants (27%) were stillborn or died in the delivery room, 86 (14%) died in the NICU, and 376 (59%) were discharged from the hospital. The risk of being registered as stillborn or not being resuscitated increased with decreasing GA below 25 weeks. The survival rates for all births and for infants admitted to a NICU were, respectively, 0% for <23 weeks, 16% and 39% for 23 weeks, 44% and 60% for 24 weeks, 66% and 80% for 25 weeks, 72% and 84% for 26 weeks, 82% and 93% for 27 weeks, and 69% and 90% for >27 weeks. For the survivors, days of mechanical ventilation decreased from a median of 37 days to 3 days and the proportion in need of oxygen at 36 weeks' postconceptional age decreased from 67% to 26% at 23 and 27 weeks' GA, respectively. At 40 weeks' postconceptional age, the respective figures were 11% and 6%. The proportion with retinopathy of prematurity (ROP) requiring treatment decreased from 33% for GA of 23 weeks to 0% for >25 weeks. Periventricular hemorrhage of more than grade 2 occurred for 6% of the survivors and significant periventricular leukomalacia occurred for 5%, with no significant association with GA. The proportion of survivors without severe neurosensory or pulmonary morbidity increased from 44% for 23 weeks' to 86% for 27 weeks' GA. Apart from ROP, the morbidity rate was not associated with GA. CONCLUSIONS: The survival rate was high and the morbidity rate at discharge home was low in the present study, compared with previous population-based studies. With the exception of ROP, the morbidity rates among the survivors were not higher at the lowest GAs, possibly because withholding treatment was considered more acceptable for the most immature infants. The need for intensive care increased markedly for survivors with the lowest GAs.

OBJECTIVE: To assess the effect of ultrasound screening on primary diagnosis, management, and prevalence of late cases of developmental dysplasia of the hip (DDH). DESIGN: A randomized, controlled trial, including 11,925 newborn infants who were allocated to receive either general, or selective or no ultrasound screening in addition to the clinical examination. In the selectivity screened group only infants with risk factors or clinical findings of DDH received an ultrasound examination. The infants were at least 27 months old at the conclusion of the study. Those with risk factors for DDH had a radiograph examination of the hips at 4.5 months of age. RESULTS: The three study groups did not differ in terms of sex distribution or positive Barlow/Ortolani tests. General ultrasound screening resulted in a higher treatment rate than in either the selective or in the no ultrasound screening groups (3.4% vs 2.0% and 1.8%, P < .0001). For infants not subjected to treatment, ultrasound screening resulted in a higher follow-up rate because of nonconclusive early findings (13%, 1.8%, 0%, respectively; P < .0001). The prevalence of late subluxation or dislocation was lower for subjects assigned to general ultrasound screening than for those subjected to selective or no ultrasound screening, but the differences were not statistically significant (0.3, 0.7, 1.3 per 1000, respectively; P = .11, test for trend). CONCLUSION: The effect of ultrasound screening in reducing the prevalence of late DDH was at best marginal despite a considerable increase in diagnostic and therapeutic efforts.

OBJECTIVE: Prone sleeping is a strong risk factor for sudden infant death syndrome (SIDS). We investigated whether the combined effect of prone sleeping position and prenatal risk factors further increased the SIDS risk. METHODS: In the Nordic Epidemiological SIDS Study, parents of SIDS victims in Denmark, Norway, and Sweden completed a questionnaire on potential risk factors for SIDS. Forensic pathologists verified the SIDS diagnosis. Four controls of the same gender, age, and place of birth were selected. This matched case-control study, which included 244 SIDS cases and 869 controls from 1992 to 1995, was analyzed by conditional logistic regression. RESULTS: Odds ratios (ORs) for prone and side sleeping compared with supine sleeping for the last sleep were 13.9 (95% confidence interval 8.2-24) and 3.5 (2.1-5.7). Infants 13 to 24 weeks old had particularly high risk in prone and side sleeping, at 28.5 (7.9-107) and 5.9 (1.6-22). OR for prone sleeping was higher in girls, at 30.4 (11-88), than in boys, 10.3 (5.5-19). We found strong combined effects of sleeping position and prenatal risk factors (more than multiplicative). The OR for prone and side sleeping was increased for infants with birth weight <2500 g, at 83 (25-276) and 36.6 (13-107); for preterm infants, at 48.8 (19-128) and 40.5 (14-115); and for intrauterine growth retarded, at 38.8 (14-108) and 9.6 (4.3-22), compared with supine position in infants without these prenatal factors. The combined effect of nonsupine positions and intrauterine growth retarded was highest among 13- to 24-week-old infants. Effects of combined presence of nonsupine sleeping positions and each of the factors of smoking in pregnancy, young maternal age, higher parity, low level of maternal education, and single motherhood were more than additive. Attributable fractions in the population for prone and side sleeping were 18.5% and 26.0%. CONCLUSIONS: Both prone and side sleeping increased the risk of SIDS. The risk was increased further in low birth weight infants, preterm infants, and infants at the age of 13 to 24 weeks, suggesting that SIDS may be triggered by nonsupine sleeping in infants with prenatal risk factors during a vulnerable period of postnatal development.