Antonius L.M. Mulder

Functional outcomes and participation in young adulthood for very preterm and very low birth weight infants: the Dutch Project on Preterm and Small for Gestational Age Infants at 19 years of age.

OBJECTIVE. Young adults who were born very preterm or with a very low birth weight remain at risk for physical and neurodevelopmental problems and lower academic achievement scores. Data, however, are scarce, hospital based, mostly done in small populations, and need additional confirmation. METHODS. Infants who were born at <32 weeks of gestation and/or with a birth weight of <1500 g in the Netherlands in 1983 (Project on Preterm and Small for Gestational Age Infants) were reexamined at age 19. Outcomes were adjusted for nonrespondents using multiple imputation and categorized into none, mild, moderate, or severe problems. RESULTS. Of 959 surviving young adults, 74% were assessed and/or completed the questionnaires. Moderate or severe problems were present in 4.3% for cognition, 1.8% for hearing, 1.9% for vision, and 8.1% for neuromotor functioning. Using the Health Utility Index and the London Handicap Scale, we found 2.0% and 4.5%, respectively, of the young adults to have ≥3 affected areas in activities and participation. Special education or lesser level was completed by 24%, and 7.6% neither had a paid job nor followed any education. Overall, 31.7% had ≥1 moderate or severe problems in the assessed areas. CONCLUSIONS. A total of 12.6% of young adults who were born very preterm and/or with a very low birth weight had moderate or severe problems in cognitive or neurosensory functioning. Compared with the general Dutch population, twice as many young adults who were born very preterm and/or with a very low birth weight were poorly educated, and 3 times as many were neither employed nor in school at age 19.

Induction of Labor versus Expectant Management in Women with Preterm Prelabor Rupture of Membranes between 34 and 37 Weeks: A Randomized Controlled Trial

In a randomized controlled trial David van der Ham and colleagues investigate induction of labor versus expectant management for women with preterm prelabor rupture of membranes.

Endothelial vasodilatation in newborns is related to body size and maternal hypertension.

Objective The fetal response to an adverse intrauterine environment – reflected in low birth weight – is thought to cause an increased risk for adult hypertension. A possible mechanism by which fetal adaptive responses contribute to hypertension is an adverse effect on endothelial function. Identifying individuals with endothelial dysfunction as early as possible may assist in understanding the inverse association between birth weight and hypertension. The present study aimed to identify determinants of endothelial vasodilatation in the first week of life. Methods One hundred and four term newborns were studied in the first week after birth with regard to maximum vasodilatation in response to acetylcholine (endothelium-dependent) and nitroprusside (endothelium-independent) in the vasculature of the forearm skin, by use of a laser-Doppler device and iontophoresis. Bivariable and multivariable linear regression with various familial, gestational and neonatal potential covariates were used for the analysis. Results In the bivariable analysis, maximum perfusion after administration of acetylcholine was positively associated with birth weight, length, head circumference and maternal education level, but negatively associated with maternal hypertension during pregnancy. In the multivariable analysis, head circumference [b = 11.9 perfusion units/z-score, P = 0.02] and hypertension during pregnancy (b = −25.3 perfusion units from nonhypertensive to hypertensive, P = 0.02) remained significantly associated. Maximum perfusion after administration of nitroprusside was not related to any of the anthropometric measures; it was, however, related to gestational age (b = −11.1 perfusion units/week, P = 0.009). Conclusion This study showed that body size, head circumference in particular, is positively associated with endothelial vasodilatation in newborns, whereas hypertension during pregnancy is inversely associated with endothelial vasodilatation.

Determinants of infant growth in four age windows: a twin study

OBJECTIVE To identify determinants of growth during infancy. STUDY DESIGN The sample included 424 twin pairs from the East Flanders Prospective Twin Survey. Multilevel regression analysis was performed and intrapair growth correlations were calculated. The main outcome measure was growth, measured in g/kg/d (0-1 month) or in change in weight z-score (0-6, 6-12 and 12-24 months). RESULTS Growth during infancy was associated with birth weight and gestational age. One z-score increase in birth weight resulted in -1.77 g/kg/d less growth from 0-1 month (P < .0001). The effect size decreased with age until -0.02 (P = .70) z-scores less growth from 12 to 24 months. Corresponding numbers for one z-score increase in gestational age decreased from 0.78 (P = .001) to 0.06 (P = .40). From 12 to 24 months, paternal height had a significant positive effect. The difference in growth similarity within the twin pair between monozygotic and dizygotic twins increased from non-significant from 0 to 1 month (P = .49) to a monozygotic:dizygotic ratio approximating 2:1 from 12 to 24 months (P = .002). CONCLUSION From 0 to 1 month, environmental factors are most important for growth, whereas genetic factors become more important over time. This is a first step in identifying age windows for future counseling and interventions on the effects of accelerated growth.

Economic analysis comparing induction of labor and expectant management in women with preterm prelabor rupture of membranes between 34 and 37 weeks (PPROMEXIL trial)

To compare the costs of induction of labor and expectant management in women with preterm prelabor rupture of membranes (PPROM).

Clinical practice: neonatal resuscitation. A Dutch consensus

The updated Dutch guidelines on Neonatal Resuscitation assimilate the latest evidence in neonatal resuscitation. Important changes with regard to the 2004 guidelines and controversial issues concerning neonatal resuscitation are reviewed, and recommendations for daily practice are provided and argued in the context of the ILCOR 2005 consensus.

Influence of Growth During Infancy on Endothelium-Dependent Vasodilatation at the Age of 6 Months

Low birth weight and accelerated infant growth are associated with cardiovascular disease in adulthood. Endothelial dysfunction is regarded as a precursor of atherosclerosis and is also related to infant growth. We aimed to examine whether an association between infant growth and endothelial function is already present during discrete periods of growth during the first 6 months of life in healthy term infants. A cohort of 104 newborns was studied in the first week after birth and reexamined at the age of 6 months. Maximum vasodilatation in response to acetylcholine (endothelium dependent) and nitroprusside (endothelium independent) was measured in the vasculature of the forearm skin, using laser Doppler flowmetry and iontophoresis. Growth was calculated as difference in Z scores for weight, length, weight-for-length, and head circumference. Multivariable multilevel linear regression was used for the analysis. Growth from 0 to 1 month (calculated as difference in weight) was the only window in the first 6 months of life that was significantly and inversely associated with endothelium-dependent vasodilatation at 6 months (b=−11.72 perfusion units per Z score, P=0.01 in multivariable analysis). Birth size was not important when considered simultaneously with infant growth. Maximum endothelium-independent vasodilatation was not associated with birth size or growth parameters. We conclude that growth in the first month of life is inversely associated with endothelium-dependent vasodilatation at the age of 6 months in healthy term infants, regardless of birth size.

Using vaginal Group B Streptococcus colonisation in women with preterm premature rupture of membranes to guide the decision for immediate delivery: a secondary analysis of the PPROMEXIL trials

To investigate whether vaginal Group B Streptococcus (GBS) colonisation or other baseline characteristics of women with preterm premature rupture of membranes (PPROM) can help in identifying subgroups of women who would benefit from immediate delivery.

Changes in genetic and environmental effects on growth during infancy.

BACKGROUND Accelerated infant growth is a possible explanation for the relation between birth weight and adult diseases. OBJECTIVE The aim of this study was to estimate the heritability of infant growth and to examine whether the genetic contribution changes with increasing or decreasing birth weight and gestational age. DESIGN Growth (change in weight z score) was analyzed in 522 infants from the East Flanders Prospective Twin Survey for age windows of 0-1, 1-6, 6-12, and 12-24 mo. Structural equation modeling was performed to estimate the relative importance of additive genetic, shared environmental, and unique environmental sources of variance. RESULTS We showed no genetic contribution to growth in the 0-1-mo growth period. However, at later ages, the heritability of growth was high at 94% (95% CI: 90%, 96%) from 1 to 6 mo, 85% (95% CI: 80%, 89%) from 6 to 12 mo, and 86% (95% CI: 77%, 91%) in the 12-24-mo growth period. Nevertheless, in the last age window, a model without genetic factors was also statistically plausible. From 0 to 1 mo, the genetic contribution to growth was low in the average birth weight range but higher at both extremes of birth weight. The genetic contribution from 0 to 1 mo increased with increasing gestational age from 36 wk of gestation onward. CONCLUSIONS This study shows that genetic factors are not important in early infant growth (0-1 mo), whereas heritability is high after 1 mo. Because many (nutritional) interventions are aimed at influencing early postnatal growth, to target long-term health, these interventions may be most successful if implemented in the first month of postnatal growth.

Genetic, maternal and placental factors in the association between birth weight and physical fitness: a longitudinal twin study.

Background Adult cardiorespiratory fitness and muscle strength are related to all-cause and cardiovascular mortality. Both are possibly related to birth weight, but it is unclear what the importance is of genetic, maternal and placental factors in these associations. Design Peak oxygen uptake and measures of strength, flexibility and balance were obtained yearly during adolescence (10–18 years) in 114 twin pairs in the Leuven Longitudinal Twin Study. Their birth weights had been collected prospectively within the East Flanders Prospective Twin Survey. Results We identified linear associations between birth weight and adolescent vertical jump (b = 1.96 cm per kg birth weight, P = 0.02), arm pull (b = 1.85 kg per kg birth weight P = 0.03) and flamingo balance (b = −1.82 attempts to stand one minute per kg birth weight, P = 0.03). Maximum oxygen uptake appeared to have a U-shaped association with birth weight (the smallest and largest children had the lowest uptake, P = 0.01), but this association was no longer significant after adjustment for parental BMI. Using the individual twin’s deviation from his own twin pair’s average birth weight, we found positive associations between birth weight and adolescent vertical jump (b = 3.49, P = 0.0007) and arm pull (b = 3.44, P = 0.02). Δ scores were calculated within the twin pairs as first born twin minus second born twin. Δ birth weight was associated with Δ vertical jump within MZ twin pairs only (b = 2.63, P = 0.009), which indicates importance of placental factors. Conclusions We found evidence for an association between adolescent physical performance (strength, balance and possibly peak oxygen uptake) and birth weight. The associations with vertical jump and arm pull were likely based on individual, more specifically placental (in the case of vertical jump) factors. Our results should be viewed as hypothesis-generating and need confirmation, but potentially support preventive strategies to optimize birth weight, for example via placental function, to target later fitness and health.