Sjögren-Larsson syndrome (SLS) was originally described as a triad of spasticity, mental retardation and congenital ichthyosis. The syndrome reflects an underlying deficiency of microsomal fatty aldehyde dehydrogenase (FALDH). We report on clinical data concerning pregnancy, labor and neonatal period in 15 patients. Pregnancies were uncomplicated, except for preterm rupture of membranes in three pregnancies, and the occurrence of preterm birth. Mean gestational age was 35.3 weeks (S.D. 2.4 weeks), and preterm birth was found in 73% of the children, while all children were born before or in the 38th week of gestation. Birth weight was normal for gestational age in all patients. The neonatal period was free from serious complications, apart from hemolytic disease in two patients. Preterm birth was found in 7% of the healthy siblings, reflecting the normal population. Prematurity and spasticity are intrinsic and concurrent parts of SLS, without causal relation. SLS should be considered in every neonate with congenital ichthyosis, especially if the child is born preterm. A possible explanation for preterm birth in SLS could be the defective inactivation of leukotriene B4 (LTB4), which recently has been demonstrated in patients with SLS.