Lisbeth B. Knudsen

The Intergenerational Transmission of Fertility in Contemporary Denmark: The Effects of Number of Siblings (Full and Half), Birth Order, and Whether Male or Female

Using the Danish Fertility Database, we investigate intergenerational fertility transmission, including the relationship between the number of children born to those aged 25 and 26 years in 1994 and the number of their full sibs and half-sibs. We find that the fertility behaviour of parents and their children is positively correlated, and that half-sibs and full sibs have broadly similar effects. We do not find, in this complete national population, the strong birth order effects reported in some earlier studies. Nor do we find evidence of a weakening of intergenerational fertility transmission over time, perhaps because the greater flexibility of lifestyles in this post-transitional phase provides the extended social space within which intergenerational continuities can manifest themselves. We show that members of large families are over-represented in subsequent generations - that they have far more kin than those from smaller families - and that intergenerational continuities in fertility behaviour play a substantial role in keeping fertility higher than it would be in the absence of such transmission.

Parent's age and the risk of oral clefts.

Background: Some malformations are clearly associated with older maternal age, but the effect of older age of the father is less certain. The aim of this study is to determine the degree to which maternal age and paternal age independently influence the risk of having a child with oral clefts. Methods: Among the 1,489,014 live births in Denmark during 1973–1996, there were 1920 children with nonsyndromic cleft lip with or without cleft palate and 956 children with nonsyndromic cleft palate. We used logistic regression to assess the impact of parental age on the occurrence of cleft lip with or without cleft palate and cleft palate. Interaction between mothers and fathers age was included in the analysis. Results: Separate analyses of mothers and fathers age showed that older age was associated with increased risk of both cleft lip with or without cleft palate and cleft palate only. In a joint analysis, both maternal and paternal ages were associated with the risk of cleft lip with or without cleft palate, but the contribution of each was dependent on the age of the other parent. In the analysis of cleft palate only, the effect of maternal age disappeared, leaving only paternal age as a risk factor. Conclusion: Both high maternal age and high paternal age were associated with cleft lip with or without cleft palate. Higher paternal age but not maternal age increased the risk of cleft palate only.

Low birth weight and preterm birth after short interpregnancy intervals

OBJECTIVE Our purpose was to study low birth weight and preterm birth after short interpregnancy intervals. STUDY DESIGN Follow-up of a cohort of a register-based random sample of women who had at least two live births in Denmark between 1980 and 1992. Frequency of preterm birth (gestational age <37 weeks) and low birth weight (<2500 gm) were studied as a function of the interpregnancy interval in 10,187 women. RESULTS Short interpregnancy intervals (< or =8 months) were associated with preterm birth but not with low birth weight. The adjusted odds ratios for preterm birth were 3.60 (95% confidence interval 2.04 to 6.35) for intervals up to 4.00 months and 2.28 (1.49 to 3.48) for intervals between 4.01 and 8.00 months compared with deliveries after 24 to 36 months, in which the risk of preterm birth was 3.5%. Risks were higher in women with a previous pregnancy at term. Social status, age, and parity were adjusted for. CONCLUSIONS Short interpregnancy intervals were associated with an increased risk of premature delivery. This risk should be taken into account when planning a new pregnancy.

Freestanding midwifery unit versus obstetric unit: a matched cohort study of outcomes in low-risk women

Objective To compare perinatal and maternal morbidity and birth interventions in low-risk women giving birth in two freestanding midwifery units (FMUs) and two obstetric units (OUs). Design A cohort study with a matched control group. Setting The region of North Jutland, Denmark. Participants 839 low-risk women intending FMU birth and a matched control group of 839 low-risk women intending OU birth were included at the start of care in labour. OU women were individually chosen to match selected obstetric/socio-economic characteristics of FMU women. Analysis was by intention to treat. Main outcome measures Perinatal and maternal morbidity and interventions. Results No significant differences in perinatal morbidity were observed between groups (Apgar scores <7/5, <9/5 or <7/1, admittance to neonatal unit, asphyxia or readmission). Adverse outcomes were rare and occurred in both groups. FMU women were significantly less likely to experience an abnormal fetal heart rate (RR: 0.3, 95% CI 0.2 to 0.5), fetal–pelvic complications (0.2, 0.05 to 0.6), shoulder dystocia (0.3, 0.1 to 0.9), occipital–posterior presentation (0.5, 0.3 to 0.9) and postpartum haemorrhage >500 ml (0.4, 0.3 to 0.6) compared with OU women. Significant reductions were found for the FMU groups use of caesarean section (0.6, 0.3 to 0.9), instrumental delivery (0.4, 0.3 to 0.6), and oxytocin augmentation (0.5, 0.3 to 0.6) and epidural analgesia (0.4, 0.3 to 0.6). Transfer during or <2 h after birth occurred in 14.8% of all FMU births but more frequently in primiparas than in multiparas (36.7% vs 7.2%). Conclusion Comparing FMU and OU groups, there was no increase in perinatal morbidity, but there were significantly reduced incidences of maternal morbidity, birth interventions including caesarean section, and increased likelihood of spontaneous vaginal birth. FMU care may be considered as an adequate alternative to OU care for low-risk women. Pregnant prospective mothers should be given an informed choice of place of birth, including information on transfer.

Danish registers on aspects of reproduction

Introduction: The establishing of three Danish population-based registers, namely the Fertility Database, the Register of Legally Induced Abortions, and the In Vitro Fertilisation register, aimed at providing data for surveying of reproductive outcome. Content: The registers include information on births, abortions, and assisted reproduction as well as selected characteristics of the women (and men) involved. Validity and coverage: Both the validity and coverage of each register are considered of high quality. Conclusion: These registers provide, both individually and in combination, unique opportunities for undertaking detailed and comprehensive research in the field of reproduction.

Induced abortion in the Nordic countries: special emphasis on young women

Background. To analyze the trends in legally induced abortions among women younger than 30 years in the five Nordic countries, Denmark, Finland, Iceland, Norway and Sweden, since the liberalized abortion laws came into force.

Socioeconomic Differences in Fetal and Infant Mortality in Scandinavia

This study demonstrates that socioeconomic differences do exist in all three Scandinavian countries, and these differences have implications for perinatal and infant survival. Using parental education as a proxy for socioeconomic conditions, the association with perinatal survival seems to be stronger in Denmark and Norway than in Sweden. For postneonatal mortality the association is equally strong in the three countries. Data from one of the countries (Norway) demonstrates the joint importance of parental education, and the association with paternal education is equally strong as that with maternal education. If father and mother have the lowest level of education, their offspring has 50 to 80% higher perinatal and infant mortality risks.These observations call for further research into the association between social variables and health in order to tease out causal relationships which might lead to future preventive actions.

Mobile Forms of Belonging

Abstract Mobility is often portrayed as the antithesis of belonging. In this article, we challenge this perspective investigating how mobility and motility influence belonging in everyday life. We develop a perspective on belonging consisting of the dimensions of mobility, people and place and conditioned by the underlying dimensions of time, resources and structures of meaning. Applying this to interview material from a case study in Aalborg, we propose a tentative typology of mobile forms of belonging. It is discussed how different rhythms, conditions of mobility and variations in mobility resources result in different scales of belonging and modes of ‘centering’.

Changing lifestyles and oral clefts occurrence in Denmark

Objective The aim of this project was to assess whether any changes in the birth prevalence of cleft lip with/without cleft palate (CL[P]) occurred in Denmark during the period 1988 through 2001. In this period an official recommendation of a supplementation of folic acid to pregnant women was introduced; furthermore, smoking among pregnant women decreased considerably. Design and Settings There are few places in which ecological studies of oral clefts are possible. Denmark provides a particularly good setting for this kind of study because of a high ascertainment and a centralized registration of subjects with cleft over the last 65 years. Participants Cleft occurrence in Denmark from 1936 to 1987 has previously been reported. Here we extend the study to include all live-born children with oral clefts born in Denmark in 1988 through 2001. Among a total of 992,727 live births, 1332 children with CL(P) were born during this period. Results and Conclusions The birth prevalence of CL(P) in Denmark has previously been found to be constant in the period 1962 through 1987, with a frequency of 1.4 to 1.5 per 1000 live births. This study showed a similar occurrence in 1988 through 2001 (birth prevalence = 1.44 per 1000 live births, 95% confidence interval = 1.37 to 1.52). The introduction of folic acid and the decrease in smoking prevalence among pregnant women do not seem to have reduced the birth prevalence. This may be due to noncompliance with the folic acid recommendation and/or only a weak causal association between folic acid and smoking and occurrence of CL(P).

Pregnancy planning and acceptance among Danish pregnant women

Objective. To study how living conditions influence pregnancy planning and acceptance among Danish women.