metabolism of visceral fat,62 higher blood pressure63 and decreased insulin sensitivity.64 In contrast to animal studies, the adverse effects of ACS in humans appear to be less prominent. A long-term follow-up in adult subjects has found that those exposed antenatally to synthetic GCs compared with placebo had similar blood 17 pressure, adiposity, blood lipids, fasting insulin concentrations, glucose tolerance and morning cortisol concentrations.65 Results from human observational studies have been a bit conflicting, with some showing no association between ACS exposure and later risk factors for cardiometabolic disease,66,67 while others have showed a small increase in blood pressure,68 slight decrease in renal clearance66, impaired β -cell function and evidence of increased aortic stiffness.69 In addition, two observational studies demonstrated increased stress reactivity in term-born children exposed antenatally to glucocorticoids.70,71 1.2.4.3 Neurodevelopmental outcome It is well known that survivors of preterm birth face an increased risk of impaired neurological function. Major neurological disabilities such as cerebral palsy (CP), hearing and visual impairment are often used as markers for quality of care but cognitive difficulties and behavioral problems are also important outcome measures. Neurodevelopmental disability (NDD) is often categorized into mild, moderate or severe depending on the status of hearing, vision, IQ and Gross Motor Function Classification System (GMCFS). The incidence of NDD varies greatly between countries. A recent meta-analysis including studies from eight developed countries showed that the proportion of moderate to severe NDD among survivors of preterm birth ranged from 43% in infants born at 22 weeks of gestation to 24% in infants born at 25 weeks of gestation. 72 In the Swedish EXPRESS-cohort born before 27 weeks of gestation, the incidence of moderate to severe NDD at 6.5 years of age was 34%.73 Major neurological disabilities are often identified early in life whereas milder deficits affecting behavioral, intellectual and educational outcome may become obvious with increasing age. These more subtle cognitive dysfunctions reported in children born preterm include lower intelligence, visual motor problems, deficient memory, delayed language skills, executive dysfunctions and social and emotional difficulties. 74 Increased prevalence of learning disabilities, ADHD and autism spectrum disorders have also been reported.75 In animal studies, exposure to ACS has been associated with reduced brain mass,76,77 delayed myelination, decreased maturation of the retina and peripheral nerves78,79 and impaired programmed apoptosis.80 Some of these effects persisted into adulthood,81 raising concerns that ACS treatment could contribute to adverse long-term neurodevelopment in individuals born preterm. However, in human studies, the outcomes after ACS exposure are much more reassuring. In RCTs, there are no significant correlation between ACS and adverse effects on later cognitive ability or neurosensory disability, including cerebral palsy. 82,83 84,85 Other results in human studies are contradictive. For example, several studies have suggested adverse effects on emotional regulation after ACS exposure, 86,87 whereas in longer term follow-up of clinical trials there have been no correlation to clinically significant disturbances in early childhood behavior, executive function or adult psychiatric illness.84,88,89 18 1.2.4.4 Pulmonary outcome The most severe pulmonary complication after preterm birth is the development of bronchopulmonary dysplasia (BPD). BPD is often defined by the need of supplemental oxygen at 36 weeks postmenstrual age and is graded into mild, moderate or severe depending on how much oxygen needed. The risk of developing BPD increases with decreasing GA, prolonged mechanical ventilation and oxygen therapy. BPD is a combined restrictive and obstructive disease where the restrictive component tends to normalize during the first years whereas the obstructive component tends to predominate later in life with asthma-like symptoms.90,91 Severe cases will be dependent on supplemental oxygen for several months to years. Individuals being born preterm but with no or only mild BPD also have an increased risk of respiratory symptoms and decreased lung function later in life than the general population.92-94 Although ACS has many beneficial effect on the fetal lung, some experimental studies in rats exposed to ACS have shown a correlation to larger and fewer alveolar air spaces in adulthood,95,96 raising concern that later lung growth may be impaired also in humans. However, in clinical studies, ACS exposure did not affect spirometric measures of lung volume or expiratory flow in childhood and adulthood.97 98 1.2.5 Repeat courses of ACS Although the beneficial effects of ACS on the fetus are very well described, many studies have suggested a transient effect from ACS. 9,11,99 It seems like the maximum benefit from ACS on the fetus occurs 24 hours to 7 days after a complete course has been given. After 7 days the positive effects have diminished. This suggests that timing of ACS administration is crucial. Diagnosing actual preterm labour has been proved to be difficult, with 30-80% of women with symptoms suggesting