Studies show that very low birthweight can be an important risk factor for mental problems, disturbed fertility and neuroendocrine dysregulation. In a regional long-term study 56 of 86 adult individuals 27 to 28 years of age with a very low birthweight were compared with normal birthweight controls. Analyses of self-reported mental health, socio-demographic factors, sex hormone levels, and hair cortisol levels showed no significant differences between the groups. However, in order to analyse subgroups with different risk factors from the newborn period or children with a variety of social background factors, larger patient groups are needed.

Aim

To assess mental health outcomes of very low birthweight (VLBW, <1500 g) subjects to adulthood and to examine salivary cortisol and hair cortisol levels and their relation to birth characteristics and mental health.

Methods

A Swedish regional cohort of 56 VLBW subjects and 55 full‐term controls were assessed at the ages 27‐28 with adult self‐reported scales and the mean of 2 days diurnal salivary cortisol and hair cortisol. The cohorts had been assessed at 15 years of age with youth self‐reported scales.

Results

There were no differences between the groups in youth self‐reported scales and adult self‐reported scores. The 24 participating VLBW girls scored lower on youth self‐reported scales externalising and total problem scores than the control girls. In adulthood, the 21 participating VLBW women had significantly higher morning concentrations of salivary cortisol than control women, P = .014. No significant associations were found between cortisol concentrations and adult self‐reported scales internalising, externalising and total scores.

Conclusion

Self‐reported mental health in VLBW subjects was comparable with normal birthweight controls indicating a satisfying transition from adolescence to adulthood. VLBW females had higher morning salivary cortisol concentrations, suggesting a gender difference. We found no correlations between cortisol and mental health.

To date several studies have investigated the intergenerational effect of preterm and small-for-gestational-age births. However, most studies excluded both twin mothers and twin offspring from the analyses. Thus, the objective of this study was to investigate the intergenerational effect of preterm birth and small for gestational age (SGA) among twins and singletons.

A prospective population based register study of mother-first-born offspring pairs recorded in the Swedish Medical Birth Register was performed. The study included 4073 twins and 264,794 singletons born in 1973-1983 and their firstborns born in 1986-2009. Preterm birth was defined as birth <37 weeks of gestation and SGA as < 2 standard deviations of the Swedish standard. Logistic regressions were performed to estimate the intergenerational effect of each birth characteristic. Adjustments were made for maternal grandmothers and mother’s socio-demographic factors in addition to maternal birth- characteristics.

Among mothers born as singletons, being born preterm was associated with an increased risk for delivering a preterm child (adjusted OR 1.39, 95% CI 1.29-1.50) while being born SGA increased the likelihood of a SGA child (adjusted OR 3.04, 95% CI 2.80-3.30) as well as a preterm child (adjusted OR 1.30, 95% CI 1.20-1.40). In twin mothers, the corresponding ORs tended to be lower and the only statistically significant association was between a SGA mother and a SGA child (adjusted OR 2.15, 95% CI 1.40-3.31). A statistically significant interaction between twinning and mother’s size for gestational was identified in a multivariate linear regression analysis indicating that singleton mothers born SGA were associated with a lower birth weight compared to mothers not born SGA.

Preterm birth and SGA appear to be transferred from one generation to the next, although not always reaching statistical significance. These effects seem to be less evident in mothers born as twins compared with those born as singletons.

Background Twinning has been shown to be associated with a reduced reproductive rate compared to singletons. This can partly be explained by the birth-characteristics pertaining to twinning as many twins are born preterm, with low birth weight or small for gestational age. However, the intergenerational reproductive rate may also be due to familial factors such as number of siblings.

Methods This is a register-based study of all men and women born in Sweden between 1973 and 1993 who were living in Sweden at 13 years of age. Data on the study objects’ own births as well as their offspring, parental socio-demographic factors were collected from Swedish population based registers. Hazard ratios for the likelihood of becoming a parent were estimated using Cox’s proportion hazard models. All models were adjusted for socio-demographic and birth characteristics.

Results Adjusting for number of siblings, socio-demographic factors and birth characteristics, twinning was associated with a decreased likelihood of becoming a first-time parent, compared with singletons both for females (HR (95% CI)=0.90 (0.88-0.93) and males (HR (95% CI)=0.96 (0.93-0.99). Having 3 or more siblings increased the chance of becoming a first-time parent among both male twins (HR (95% CI)=1.17 (1.08-1.27)) and singletons (HR (95% CI)=1.16 (1.15-1.18)) compared to having fewer than 3 siblings. This increased likelihood of becoming a parent was also present among female twins (HR (95% CI)=1.18 (1.10-1.26)) and singletons (HR (95% CI)=1.22 (1.21-1.24)).

Conclusions Twins have a decreased likelihood of becoming a parent compared to singletons even when adjusting for number of siblings.

An association between preterm birth and an increased risk of childhood asthma has been demonstrated, but the importance of intrauterine growth retardation on asthma risk is unclear. less thanbrgreater than less thanbrgreater thanUsing data from Swedish health registers, infant characteristics and childhood asthma were studied. Analyses were made using Mantel-Haenszel methodology with adjustment for year of birth, maternal age, parity, smoking in early pregnancy and maternal body mass index. Preterm birth, birth weight and birth weight for gestational week were analysed and childhood asthma was evaluated from prescriptions of anti-asthmatic drugs. Neonatal respiratory problems and treatment for them were studied as mediating factors. less thanbrgreater than less thanbrgreater thanBoth short gestational duration and intrauterine growth retardation appeared to be risk factors and seemed to act separately. The largest effect was seen from short gestational duration. Use of mechanical ventilation in the newborn period and bronchopulmonary dysplasia were strong risk factors. A moderately increased risk was also seen in infants born large for gestational age. less thanbrgreater than less thanbrgreater thanWe conclude that preterm birth is a stronger risk factor for childhood asthma than intrauterine growth disturbances; however, the latter also affects the risk, and is also seen in infants born at term.

Objectives To investigate a proposed association between in vitro fertilisation (IVF) and child asthma. less thanbrgreater than less thanbrgreater thanDesign The risk for asthma after IVF was estimated as ORs using Mantel-Haenszel analysis. less thanbrgreater than less thanbrgreater thanSetting The Swedish Medical Birth Register. less thanbrgreater than less thanbrgreater thanPatients Of the 2 628 728 children born in 1982-2007 and surviving the perinatal period, 31 918 were conceived by IVF. Presence of asthma was defined as at least five prescriptions of antiasthmatic drugs during the period 1 July 2005-31 December 2009 according to the Swedish Prescribed Drug Register (115 767 children, 2323 of whom were born after IVF). less thanbrgreater than less thanbrgreater thanResults A significantly increased risk for asthma, albeit small, was found in children conceived by IVF (aOR 1.28, 95% CI 1.23 to 1.34), increasing the absolute risk from 4.4% to 5.6%. The risk increase for asthma was the same in boys and girls, in singletons and twins, and after caesarean section and vaginal delivery. The risk was higher for preterm than term singletons. For children with a low Apgar score, respiratory diagnoses, mechanical ventilation, continuous positive airway pressure or neonatal sepsis, the effect of IVF on asthma risk was low and statistically non-significant. Adjustment for length of involuntary childlessness eliminated the effect, and removal of infants whose mothers had used antiasthmatics in early pregnancy reduced the risk. less thanbrgreater than less thanbrgreater thanConclusions This study verifies an association between IVF and asthma in children. This can be partly explained by neonatal morbidity and by maternal asthma acting as mediators, but the main risk factor is parental subfertility. The mechanism for this is unclear.

Children born with non-optimal birth characteristics — that is, are small for gestational age and/or preterm — have an increased risk for several long-term effects such as neurological sequelae and chronic disease. The purpose of this study was to examine whether twins exhibited a different outcome, compared with singletons, in terms of hospitalization during adolescence and early adulthood, and to what extent differences remain when considering the divergence in birth characteristics between singletons and twins. Persons born between 1973 and 1983 in Sweden and surviving until age 13 were included and followed until the end of 2006. Data on birth characteristics, parental socio-demographic factors, and hospitalizations were collected from national registers. Adjusting for parental socio-demographic factors, twins had a higher risk of being hospitalized than singletons (odds ratio, OR = 1.17, 95% confidence interval, CI = 1.10–1.25) and more often due to ‘Congenital anomalies’ (OR = 1.18, 95% CI = 1.06–1.28), ‘Infections’ (OR = 1.14; 95% CI = 1.08–1.20), ‘External causes of illness’ (OR = 1.10, 95% CI = 1.06–1.15), and ‘Diseases of the nervous system’ (OR = 1.18, 95% CI = 1.10–1.26). Stratifying for birth characteristics, this difference diminishes, and for some diagnoses non-optimal twins seem to do slightly better than non-optimal singletons. Thus, twins with non-optimal birth characteristics had a lower risk of hospitalization than non-optimal singletons on, for example, ‘Congenital anomalies’ and ‘Diseases of the nervous system’ (OR = 0.86, 95% CI = 0.77–0.96; OR = 0.88, 95% CI = 0.81–0.97, respectively) and Total (any) hospitalization (OR = 0.87, 95% CI = 0.83–0.92). Among those with optimal birth characteristics, twins had an increased hospitalization due to ‘External causes of illness’ (OR = 1.07, 95% CI = 1.02–1.13) compared with optimal singletons. Twins have higher hospitalization rates than singletons. In stratifying for birth characteristics, this difference diminishes, and for some diagnoses, non-optimal twins seem to do less poorly than non-optimal singletons.

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Background: Fetometry dating of gestational age is the gold standard in most developed countries but may have some inborn errors. Dating pregnancies after in vitro fertilization can be used for the evaluation of fetometric studies and for studies of variables which may affect them. less thanbrgreater than less thanbrgreater thanMethods: We compared the actual gestational age of 9543 singleton and 869 twin pregnancies with estimates based on second-trimester fetometry. Mean gestational age, percentage of births classified as preterm, and skewness of the distribution of differences between actual and estimated gestational age were studied. Subanalyses were made of data on singletons for males and females, for infants born to overweight or obese women or to smoking women, for infants judged to be small or large for gestational age, and on twins. less thanbrgreater than less thanbrgreater thanResults: In the majority of cases, good agreement was found between actual and estimated gestational age but in singletons there was an excess of positive differences resulting in a moderate over-estimate of the rate of preterm births (8%), more marked for females (11%) than for males (6%) and increased for infants born to overweight (7%) or obese (16%) mothers. Singleton infants born small for gestational age also showed an excess of positive differences (3%). These differences were less marked for twins. less thanbrgreater than less thanbrgreater thanConclusions: In most IVF pregnancies, routine fetometry correctly predicts gestational age but deviations exist which indicate that ultrasound underestimates the age of fetuses that will be born small for gestational age and when the woman is obese. The differences between actual age and estimates based on fetometry seem to be smaller than those between estimates based on last menstrual period and fetometry.

Background Maternal use of some drugs, notably paracetamol and drugs for gastroesophageal reflux, has been associated with an increased risk of childhood asthma in the child. We wanted to analyze these associations with consideration to the confounding of maternal asthma. Methods Childhood asthma was identified from the Swedish National Prescription Register and maternal drug use during the latter part of pregnancy from antenatal records, computerized in the Swedish Medical Birth Register. Risks were estimated as odds ratios (OR) with 95% confidence intervals, using MantelHaenszel technique with adjustment for year of birth, maternal age, parity, smoking habits, and BMI. Results A statistical association between maternal use of many different drugs, including paracetamol, and childhood asthma existed but was mainly due to concomitant drug use, related to maternal asthma. The only associations that appeared to be true were with drugs for gastroesophageal reflux (adjusted (OR) = 1.32, 95% CI, 1.181.54) and with opiates (adjusted OR = 1.56 (96% CI, 1.052.34). Conclusions Maternal use of paracetamol did not seem to increase the risk of childhood asthma, but the previously described association with drugs for gastroesophageal reflux was supported. The analysis is complicated by the confounding from maternal asthma.