Stefan Johansson

Karolinska Institutet | KI · Department of Medicine, Solna

Background: Preterm birth (<37 completed gestational weeks) has been linked to pulmonary hypertension (PH), but the relationship to severity of preterm birth has not been studied. Objectives: We investigated associations between extremely (<28 weeks), very (28-31 weeks), moderately (32-36 weeks) preterm birth, early-term birth (37-38 weeks) and...

Aim The aim of this study was to investigate how individual markers for birth asphyxia, so-called A-criteria, were associated with the probability of receiving therapeutic hypothermia. Methods This population-based cohort study included 1336 live born singleton term infants with any A-criterion in the Stockholm-Gotland Region, Sweden during 2008 t...

While probiotics are reported to reduce the risks of neonatal morbidities, less is known about probiotics and feeding tolerance. With this retrospective cohort study, we investigate whether introduction of probiotic supplementation as the standard of care was associated with fewer neonatal morbidities and improved feeding tolerance in very preterm...

Introduction Jusqu’à récemment, les études sur le devenir des enfants nés prématurément se sont principalement intéressées aux enfants nés avant 32 semaines d’aménorrhée (SA) alors que ceux nés entre 32 et 36 SA représentent la majorité des enfants nés prématurément. L’objectif de ce travail était d’évaluer le devenir neurologique des enfants nés m...

Background The contribution of adverse consequences of preterm birth to gestational-age-related risk of cerebral palsy (CP) has rarely been studied. We aimed to assess the potential mediating roles of neonatal morbidity on the association between gestational age and risk of CP. Methods In this Swedish population-based study, 1 402 240 singletons b...

Objective: To assess risk for neonatal morbidities among infants born late preterm at 35-36 gestational weeks, early-term (37-38 weeks), and late-term (41 weeks) infants, compared with full-term (39-40 weeks) infants. Study design: This nationwide population-based cohort study included 1,650,450 non-malformed liveborn singleton infants born at 3...

( N Engl J Med . 2020;383:49–57) Neonatal death in preterm infants is associated with a number of factors, including gestational age, sex, and Apgar scores. Yet, as a predictor of neonatal survival, a low Apgar score may reflect biological immaturity in an otherwise healthy infant rather than fetal depression. Moreover, a recent policy statement of...

(Abstracted from N Engl J Med 2020;383:49–57) Preterm birth, defined as birth ≤36 weeks' gestational age (GA), is the main cause of neonatal death, although numerous other factors can affect this risk. For example, studies have shown that very preterm infants (infants born at ≤31 weeks' gestation) have a lower risk of neonatal death if they have a...

Background Gestational age is the major determinant of neonatal death (death within the first 28 days of life) in preterm infants. The joint effect of gestational age and Apgar score on the risk of neonatal death is unknown. Methods Using data from the Swedish Medical Birth Register, we identified 113,300 preterm infants (22 weeks 0 days to 36 wee...

Aim Neonatal jaundice is associated with higher risk of attention deficit hyperactivity disorder (ADHD), but it is unclear if the association is influenced by genetic and other familial factors. In this large population‐based study, we investigated the association between neonatal jaundice and ADHD while adjusting for familial factors. Methods We...

Background: Little is known about the associations between maternal body mass index (BMI) and asphyxia-related morbidity in preterm infants (<37 weeks). We aimed to investigate associations between maternal BMI in early pregnancy and severe asphyxia-related neonatal complications in preterm infants (<37 weeks) and to examine whether possible assoc...

Background: Maternal overweight and obesity are related to risks of pregnancy and delivery complications that, in turn, are associated with newborn infections. We examined the associations between early pregnancy body mass index (BMI; kg/m2) and risk of early-onset neonatal bacterial sepsis (EOS). Methods: We conducted a nationwide population-ba...

Objective: We analyzed associations between maternal bereavement the year before or during pregnancy and total and cause-specific infant mortality (IM). Methods: We studied live singleton births from the Danish (1978-2008) and Swedish Medical Birth Registers (1973-2006) (N=5,114,246). Information on maternal sociodemographic, pregnancy- and heal...

Background Metabolic acidosis, measured in arterial umbilical cord blood at birth, is the most accepted definition of birth asphyxia. The aim of the study was to investigate the rates of metabolic acidosis across the entire range of Apgar score values (0–10) at 1, 5, and 10 min in term infants. Methods In a population-based Swedish cohort of birth...

Background: Risks of neonatal and long-term neurological outcomes are influenced by metabolic acidosis at birth and by reduced Apgar scores, even within the normal range (7-10). Objective: To analyse associations between metabolic acidosis at birth and risks of reduced Apgar scores within the normal range. Methods: In a Swedish cohort of term...

Introduction: Cerebral palsy (CP) is a lifelong disorder with a high rate of comorbidities and complications. We hypothesized that women with CP are at increased risk of adverse pregnancy outcome. Material and methods: In this nationwide population-based cohort study 1997-2011, we examined the outcome of 770 births in women with CP vs. 1,247,408...

Objectives To calculate diagnostic values of the femoral pulse palpation to detect coarctation of the aorta or other left-sided obstructive heart anomalies in newborn infants. Design Population-based cohort study. Setting Stockholm-Gotland County 2008–2012. Patients All singleton live-born infants without chromosomal trisomies, at ≥35 gestationa...

Objective: To investigate whether maternal overweight and obesity increased the risk of fetal acidosis measured in umbilical cord arterial blood after delivery. Study design: Population-based cohort study of 84,785 term (≥37 weeks) infants. Logistic regression was used to estimate risks of fetal acidosis in umbilical cord arterial blood. Fetal a...

We report a nosocomial outbreak with group B streptococci (GBS) in a level two neonatal intensive care unit (NICU) at Sachs' Children and Youth Hospital, Stockholm, Sweden, in 2014. There were five very preterm infants with severe late onset septicemia and 10 further infants were colonised. Pulsed-field gel electrophoresis and multi locus sequence...

Background Birth by cesarean section is associated with increased risks of immune disorders. We tested whether establishment of immune function at birth relates to mode of delivery, taking other maternal and infant characteristics into account. Methods and findings Using a prospectively collected database, we retrieved information on maternal and...

Maternal characteristics of 6,014 singleton live-birth at 35–42 weeks of gestation, and numbers and rates of TREC- and KREC-levels in the lowest quintile. (DOCX)

Risks of a low TREC- and KREC-levels related to maternal characteristics of 6,014 singleton live-births at 35–42 weeks of gestation. (DOCX)

Risks of a low TREC- and KREC-levels related to characteristics of 5,681 singleton infants born at 35–42 weeks of gestation, to mothers without diabetes or hypertensive disease. (DOCX)

(Abstracted from JAMA 2017;317(9):925–936) Prevalence of cerebral palsy (CP) rose between 1998 and 2006, and few preventable risk factors are known for this most common pediatric motor disability. Maternal obesity, a risk factor for neonatal complications such as preterm delivery and asphyxia-related neonatal morbidities, has been suggested to be a...

The ABC of paediatric ECG interpretation In paediatric patients, ECG is used as a tool for investigation of arrhythmias, chest pain, syncope, intoxications and congenital heart abnormalities. Paediatric ECGs differ significantly from adult ECGs, and change gradually during childhood, largely because of the changes that start with the transition of...

( JAMA . 2016;316(4):410–419) Late preterm and early term births occurring either spontaneously or through obstetric interventions such as labor induction or cesarean delivery have raised concerns due to the risks of adverse neonatal and childhood outcomes. Hence guidelines in the United States now recommend avoiding nonmedically indicated elective...

Importance Maternal overweight and obesity are associated with increased risks of preterm delivery, asphyxia-related neonatal complications, and congenital malformations, which in turn are associated with increased risks of cerebral palsy. It is uncertain whether risk of cerebral palsy in offspring increases with maternal overweight and obesity sev...

Objective: The associations between duration of second stage of labor, pushing time and risk of adverse neonatal outcomes are not fully established. Therefore, we aimed to examine such relationships. Study design: A population-based cohort study including 42 539 nulliparous women with singleton infants born in cephalic presentation at ⩾37 gestat...

Objective: The objective of the study was to examine normal variations of umbilical cord arterial pH by gestational age (GA). Study design: Population-based cohort study of 46 199 infants born from 2008 to 2014 in Stockholm, Sweden, with GA 28 to 42 weeks, Apgar score ⩾7 at 5 min, non-instrumental vaginal delivery, and birth weight for GA⩾3rd an...

(Abstracted from JAMA 2016;316(4):410–419) Late-preterm and early-term births occurring spontaneously or through obstetric interventions including labor induction or cesarean delivery are a cause for concern because of consequent risks of adverse neonatal and childhood outcomes. Hence, recommendations in the United States have been to decrease nonm...

Aims/hypothesis: Women with type 1 or type 2 diabetes are at increased risk of pre-eclampsia. Overweight and obesity are associated with an increased risk of pre-eclampsia in women without diabetes. The aim of the study was to investigate the impact of maternal overweight and obesity on the risk of pre-eclampsia in women with type 1 diabetes or ty...

Aim: This study compared obstetric units practicing routine or selective umbilical cord blood gas analysis, with respect to the risk of missing samples in high-risk deliveries and in infants with birth asphyxia. Methods: This was a Swedish population-based cohort study that used register data for 155,235 deliveries of live singleton infants betw...

Background: Gestational age estimation by last menstrual period (LMP) vs. ultrasound (or best obstetric estimate in the US) may result in discrepant classification of preterm vs. term birth. We investigated whether such discrepancies are associated with adverse infant outcomes. Methods: We studied singleton livebirths in the Medical Birth Regist...

Importance Clinicians have been urged to delay the use of obstetric interventions (eg, labor induction, cesarean delivery) until 39 weeks or later in the absence of maternal or fetal indications for intervention. Objective To describe recent trends in late preterm and early term birth rates in 6 high-income countries and assess association with us...

Background and objectives: Data from clinical trials support the use of continuous positive airway pressure (CPAP) for initial respiratory management in preterm infants, but there is concern regarding the potential failure of CPAP support. We aimed to examine the incidence and explore the outcomes of CPAP failure in Australian and New Zealand Neon...

In a population-based case-control study, we investigated whether familial confounding influenced the associations between maternal overweight/obesity and risks of stillbirth and infant mortality by including both population and sister controls. Using nationwide data from the Swedish Medical Birth Register (1992–2011), we included all primiparous w...

Maternal overweight and obesity are associated with increased risks of birth-asphyxia-related outcomes, but the mechanisms are unclear. If a change of exposure (i.e., maternal body mass index [BMI]) over time influences risks, this would be consistent with a causal relationship between maternal BMI and offspring risks. Our objective was to investig...

Maternal inter-pregnancy weight change and risk of low Apgar score (0–6) at 5 min, meconium aspiration and neonatal seizures: live singleton term infants of mothers without obesity-related pregnancy complications in second pregnancy. (DOCX)

Checklist of items that should be included in reports of observational studies. (DOC)

Maternal inter-pregnancy weight change and risk of low Apgar score, neonatal seizures, and meconium aspiration in second offspring: mothers with BMI 18.5–24.9 kg/m2 in second pregnancies with live singleton term infants at second birth, Sweden 1992–2012. (DOCX)

Characteristics of women with and without data on inter-pregnancy weight change. (DOCX)

Analysis plan. (DOCX)

Background: As a result of antenatal screening, abortion of fetuses with Down syndrome has become increasingly common. Little is known about the cardiovascular phenotype in infants with Down syndrome born today. Methods: Population-based cohort study based on national health registers including 2588 infants with Down syndrome, live-born in Swede...

Aim: This study examined maternal and pregnancy risk factors for haemolytic and non-haemolytic neonatal jaundice in a large population-based cohort study. Methods: We conducted a cohort study of 1,019,220 singleton live births from the Swedish medical birth register from 1987-2002, using information on neonatal jaundice and maternal and pregnanc...

To investigate associations between maternal overweight and obesity and infant mortality outcomes, including cause-specific mortality. Population based cohort study. 1 857 822 live single births in Sweden 1992-2010. Associations between maternal body mass index (BMI) in early pregnancy and risks of infant, neonatal, and postneonatal mortality, over...

Background: The optimal timing of pharmacological treatment for patent ductus arteriosus (PDA) in extremely preterm infants is unknown. Objective: To investigate whether timing of pharmacological PDA treatment is associated with a risk of secondary PDA surgery or death before 3 months of age, or bronchopulmonary dysplasia (BPD) in extremely pret...

Although the risks of adverse pregnancy outcomes associated with anti-D antibodies are well-recognized, much less is known concerning alloimmunization with other red blood cell antibodies detected during routine maternal screening. To date, most reports of adverse pregnancy outcomes associated with non-anti-D antibodies have been from small case st...

Background: Maternal overweight and obesity increase risks of pregnancy and delivery complications and neonatal mortality, but the mechanisms are unclear. The objective of the study was to investigate associations between maternal body mass index (BMI) in early pregnancy and severe asphyxia-related outcomes in infants delivered at term (≥37 weeks)...

To investigate potential violations of patient confidentiality or other breaches of medical ethics committed by physicians and medical students active on the social networking site Twitter. Population-based cross-sectional observational study. The social networking site Twitter (Swedish-speaking users, n=298819). Physicians and medical students (Sw...

Preterm birth is a leading cause of infant mortality, morbidity, and long-term disability, and these risks increase with decreasing gestational age. Obesity increases the risk of preterm delivery, but the associations between overweight and obesity and subtypes of preterm delivery are not clear. To study the associations between early pregnancy bod...

Rationale and Objectives: Serum cholesterol (S-Chol) levels have been reported to affect blood pressure at young age and hypercholesterolemia might promote the development of hypertension (HBP) probably by activating tissue renin-angiotenin system (RAS). The aim of the present study was to assess the rate of developement of stable HBP over a period...

Introduction In humans, pregnancy normally lasts nine months, ending with term birth after approximately 40 gestational weeks. Preterm birth is arbitrarily defined as delivery before 37 weeks, and could be further classified as moderately, very or extremely preterm, occurring at 32-36, 28-31, and ≤ 27 weeks, respectively. Historically, there has be...

We examined whether an association between preterm birth and risk of autistic disorders could be explained by pregnancy complications or neonatal morbidity. This Swedish, population-based, case-control study included 1216 case subjects with autistic disorders who were born between 1987 and 2002 and 6080 control subjects who were matched with respec...

Delivery by C-section (CS) has been associated with increased risk for allergy, diabetes and leukaemia. Whereas the underlying cause is unknown, epigenetic change of the genome has been suggested as a candidate molecular mechanism for perinatal contributions to later disease risk. We hypothesized that mode of delivery affects epigenetic activity in...

We investigated whether infections with Parvovirus B19 and Herpes viruses in early pregnancy increase risks of second trimester miscarriage or delivery before 32 gestational weeks. Blood samples taken in early pregnancy were analyzed for Parvovirus B19 or Herpes viruses. Viremia was found in blood samples of 11 (4.7%) women with second trimester mi...

Low birth weight has been associated with an increased risk of type 2 diabetes in adulthood. Poor fetal nutrition has been suggested to explain this association. Our objective was to determine whether genetic factors contribute to the association between low birth weight and subsequent risk of type 2 diabetes. We retrieved information from original...

Background: Low birth weight has been associated with an increased risk of type 2 diabetes in adulthood. Poor fetal nutrition has been suggested to explain this association. Our objective was to determine whether genetic factors contribute to the association between low birth weight and subsequent risk of type 2 diabetes. Methods: We retrieved info...

Impaired renal development during foetal life is a proposed mechanism for adult hypertension in people born small. Whether preterm birth contributes to such adverse development is still unclear. We investigated the selective contributions from foetal growth restriction or preterm birth to renal function and volume in children with low birth weight....

Studies have found associations between low birth weight and increased risks of cardiovascular diseases in adulthood. However, these associations could be due to confounding by genetic or socioeconomic factors. We performed a study on Swedish like-sexed twins with known zygosity who were born from 1926 to 1958. First, to obtain an overall effect of...

Low birth weight is associated with cardiovascular disease. The underlying mechanisms are unknown. We hypothesized that perinatal stress alters autonomic regulation of the cardiovascular system. In this study, catecholamines, heart rate (HR) and blood pressure (BP) were measured in healthy children with low birth weight. This clinical study include...

We sought to study whether the association between being born small for gestational age and risk for low intellectual performance was modified by gestational age. A population-based cohort study was conducted of 352,125 boys who were born between 28 and 43 completed weeks of gestation from 1973 to 1981 in Sweden. Risk for low intellectual performan...

Survivors of preterm birth constitute a new generation of young adults, but little is known about their long-term health. We investigated the association between gestational age (GA) and risk of high blood pressure (HBP) in young Swedish men and whether GA modified the risk of HBP; ie, whether HBP was related to being born small for gestational age...

Background: Low birth weight due to fetal growth restriction is an established risk factor for hypertension later in life, but the effect of preterm birth is less well studied.

To elucidate the role of level of care in combination with other perinatal risk factors for infant death in very preterm deliveries. Population-based cohort study. Sweden, 1992-1998. Singleton infants (2285) born at 24 to 31 completed weeks of gestation to primiparous women. Infant mortality. The rate of infant mortality increased from 5% among inf...

Unlabelled: The increased body water in pregnant women and the birth-related activation of water-sparing systems contribute to a high risk of perinatal water intoxication if the mother drinks too much water during labour. This study reports on four newborn term infants and one mother presenting with life-threatening symptoms due to hyponatraemia f...

An analysis was made of the incidence and treatment regimen of symptomatic patent ductus arteriosus (PDA) in 95 preterm infants treated 1997-1999 in a level three intensive care unit in Stockholm. 47 infants (49 percent) had PDA. Of these 17 infants were managed conservatively (fluid restriction and diuretics), 13 were treated with indomethacin, 10...

Guidelines for the clinical investigation of young children with stridor and sleep apnea are presented. Clinical examination and flexible videolaryngoscopy performed in local anaesthesia are the most important diagnostic tools for this group of children. If the impairment is severe or an objective evaluation is needed the child should also undergo...

Utredning och behandling av luft- vägsproblematik hos spädbarn är ett av många områden där synsätten har för- ändrats. Uppfattningen att vanliga sym- tom som ljudlig andning och andnings- uppehåll inte behöver ha negativa kon- sekvenser för ett barns hälsotillstånd har ifrågasatts och ersatts av ett mer ak- tivt förhållningssätt. Den ökade uppmärks...