Morten Hedegaard

Psychological distress in pregnancy and preterm delivery.

OBJECTIVE--To investigate if psychological distress during pregnancy is associated with increased risk of preterm delivery. DESIGN--Prospective, population based, follow up study with repeated measures of psychological distress (general health questionnaire), based on the use of questionnaires. SETTING--Antenatal care clinic and delivery ward, Aarhus University Hospital, Denmark. SUBJECTS--8719 women with singleton pregnancies attending antenatal care for the initial visit between 1 August 1989 and 30 September 1991; 5872 women (67%) completed all questionnaires. MAIN OUTCOME MEASURE--Preterm delivery. Estimation of gestational age at delivery was mainly based on early ultrasound measurements. RESULTS--In 197 cases (3.6%) the woman delivered prematurely (less than 259 days). A dose-response relation between psychological distress in the 30th week of pregnancy and risk of preterm delivery was found, but distress measured in the 16th week was not related to preterm delivery. Control of confounding was secured by the use of multivariate logistic regression models. Relative risk for preterm delivery was 1.22 (95% confidence interval 0.84 to 1.79) for moderate distress and 1.75 (1.20 to 2.54) for high distress in comparison to low distress. CONCLUSIONS--Psychological distress later in pregnancy is associated with an increased risk of preterm delivery. Future interventional studies should focus on ways of lowering psychological distress in late pregnancy.

Do stressful life events affect duration of gestation and risk of preterm delivery

&NA; The present study was designed to test the relation between stressful life events experienced during pregnancy and the risk of preterm delivery and shortened duration of pregnancy. We collected data prospectively in a general population sample, including repeated questionnaire measures of exposure to stressful life events during pregnancy. Between August 1989 and September 1991, 8,719 Danish‐speaking women with singleton pregnancies attended antenatal care. Of these women, 5,873 (67%) completed all questionnaires. When indicating an event, the woman was asked to rate the amount of stress induced by this event. Measurement of gestational duration was primarily based on early ultrasound scan. When we evaluated life events independently of the individuals appraisal, we found no association with duration of gestation or risk of preterm delivery. In contrast, life events assessed by the subject as highly stressful were associated with shorter mean duration of gestation and increased risk of preterm delivery. This association was observed primarily with events experienced between the 16th and 30th week of gestation. Women who had one or more highly stressful life events had a risk of preterm delivery 1.76 times greater than those without stressful events (95% confidence interval = 1.15‐2.71). We found no evidence for a buffering effect of social support. (Epidemiology 1996;7:339‐345)

Stress and salivary cortisol during pregnancy.

The purpose of this study was to determine whether exposure to stressful life events was associated with changes in levels of circulating cortisol during pregnancy in a population of 603 pregnant women. The participating pregnant women filled out a questionnaire and collected a morning and evening sample of saliva in early pregnancy (median 14th gestational week) and in late pregnancy (median and 30th gestational week). They were asked to report the number of life events experienced during first and second trimester, respectively, and were asked to rate the intensity of the experienced events. Complications related to the pregnancy such as vaginal bleeding and suspected growth retardation were registered and the women were asked about concerns about their pregnancy. The salivary samples were analyzed for cortisol and the levels were higher in late than in early pregnancy. In late pregnancy women exposed to more than one life event or were concerned about pregnancy complications during second trimester had a higher evening cortisol level, whereas morning values were unaffected. After adjustment for smoking women who experienced more than one very stressful life event had 27% higher evening cortisol concentrations (95% confidence intervals: 1-59%). Women with worries about pregnancy complications had 27% (95% confidence intervals: 2-57%) higher levels. In early pregnancy women reporting stressful life events did not have higher evening cortisol levels, but tended to have a blunted morning HPA response. In conclusion, we found differences in the associations between chronic stress in early and late pregnancy and cortisol levels indicating that the response to chronic stress is dependent on the stage of the pregnancy.

Gestational Age and Birth Weight in Relation to School Performance of 10-Year-Old Children: A Follow-up Study of Children Born After 32 Completed Weeks

BACKGROUND. Children born extremely premature (<28 weeks) or with a very low birth weight (<1500 g) have a poorer school performance than children born at term with a normal birth weight. Much less is known about children of higher gestational ages and birth weights. We studied gestational age after 32 completed weeks and birth weight in relation to the childs school performance at the age of 10 years. METHODS. We performed a follow-up study of 5319 children born between January 1990 and June 1992. We got the information on birth weight and gestational age from birth registration forms; when the children were between 9 and 11 years of age, we gathered information about their school performance (reading, spelling, and arithmetic) from questionnaires completed by the parents and the childrens primary school teachers. RESULTS. The association between birth weight and reading, as well as spelling and arithmetic disabilities, showed a graded relationship, with children who weighed <2500 g having the highest risks. Even children who weighed between 3000 and 3499 g had an increased risk of all 3 learning disabilities compared with children who weighed between 3500 and 4000 g. This association persisted after adjustment for potential cofounders and when the analyses were restricted to children born at term (39–40 weeks of gestation), suggesting that the association could not be explained by a low gestational age. Compared with children born at term, reading and spelling difficulties were more often found among children born at gestational age 33 to 36 weeks and 37 to 38 weeks, whereas there was no relation between gestational age and arithmetic difficulties. CONCLUSIONS. Gestational age and birth weight were associated with school performance in the 10-year-old child and the association extended into the reference range of both birth weight and gestational age.

Bias in studies of preterm and postterm delivery due to ultrasound assessment of gestational age.

Ultrasound measurement of fetal dimensions is widely used for estimating gestational age. A little-discussed limitation of this method is that variations in fetal size at a given stage of pregnancy are converted to differences in gestational age. Factors that affect pregnancy duration often affect fetal size also. We explore how the effect of such factors may he biased when gestational age is determined by ultrasound. We selected 3,606 women with singleton pregnancies (1989–1991) who had an early ultrasound measurement of fetal biparietal diameter (BPD) and a good-quality history of last menstrual period (LMP). Using the two measures of gestational age, we estimated risk of preterm and postterm delivery for female babies vs males and for smoking women vs nonsmoking women. There was a 13% excess of preterm delivery among female babies when gestational age was determined by ultrasound, but no excess when gestational age was defined by LMP. For postterm delivery, female babies had a 19% lower risk with ultrasound-defined age, but no deficit with LMP-defined age. We found a similar bias with ultrasound in the analysis of maternal smoking. Thus, factors that reduce fetal size inflate the risk of preterm delivery and deflate the risk of postterm delivery when gestational age is based on ultrasound measurement of the fetus. This bias can distort the relative risk of preterm or postterm delivery by 10–20%. (Epidemiology 1995; 6:533–537)

Smoking during pregnancy and preterm birth.

Objective To evaluate the association between smoking during pregnancy and preterm birth.

Several genetic and environmental factors influence cord blood IgE concentration

Cord blood samples were collected from a birth cohort of 2631 infants to elucidate the association between genetic and environmental factors and fetal production of IgE. The cord blood IgE values were treated both as a continuous and as a dichotomous variable in the statistical analyses. Multivariate analysis was used to control for confounding factors. Infants with single and biparental atopic heritage had higher IgE concentrations in cord plasma than children of parents without atopy. Multiple logistic regression analysis revealed a significant association to maternal allergic eczema or perennial rhinitis. The cord blood IgE concentration varied with month of birth with peaks in late autumn. This seasonal variation was not related to parental atopic disease. Boys had significantly higher levels of IgE and more often elevated IgE values (≥0.5 kU/1) than girls. Alcohol and caffeine consumption by the mothers during pregnancy were both significantly associated with elevated IgE concentration. There was also a relation between mothers prepregnant weight and elevated CB‐IgE levels. No significant association was observed between maternal smoking and cord plasma IgE levels. The fact that many factors presumably not related to child allergy seem to influence the regulation of fetal IgE production, could explain the questionable value of cord blood IgE in predicting allergy in childhood.

Standing at work and preterm delivery

Objective Guidelines in some European countries and the United States suggest that pregnant women should avoid prolonged standing and heavy lifting in the workplace during the second and third trimester of pregnancy. However, results from epidemiological studies on this topic are ambiguous. The aim of this study was to evaluate the influence of standing and walking at work in the second trimester on preterm delivery in a population with a low frequency of other workplace hazards.

Maternal consumption of coffee during pregnancy and stillbirth and infant death in first year of life: prospective study

Abstract Objective: To study the association between coffee consumption during pregnancy and the risk of stillbirth and infant death in the first year of life. Design: Prospective follow up study. Setting: Aarhus University Hospital, Denmark, 1989-96. Participants: 18 478 singleton pregnancies in women with valid information about coffee consumption during pregnancy. Main outcome measures: Stillbirth (delivery of a dead fetus at ≥28 weeks gestation) and infant death (death of a liveborn infant during the first year of life). Results: Pregnant women who drank eight or more cups of coffee per day during pregnancy had an increased risk of stillbirth compared with women who did not drink coffee (odds ratio=3.0, 95% confidence interval 1.5 to 5.9). After adjustment for smoking habits and alcohol intake during pregnancy, the relative risk of stillbirth decreased slightly. Adjustment for parity, maternal age, marital status, years of education, occupational status, and body mass index did not substantially change the estimates of association. There was no significant association between coffee consumption and death in the first year of life after adjustment for smoking habits during pregnancy. Conclusion: Drinking coffee during pregnancy is associated with an increased risk of stillbirth but not with infant death. What is already known on this topic Results from studies in monkeys suggest that high daily doses of caffeine in pregnancy increase the risk of stillbirth, but evidence from studies in humans has been lacking What this study adds Pregnant women who drank eight or more cups of coffee a day had more than twice the risk of stillbirth compared with women who did not drink coffee during pregnancy

Episiotomy and perineal lesions in spontaneous vaginal deliveries

Objective To evaluate the influence of mediolateral episiotomy on the perineal state after spontaneous, singleton vaginal deliveries with fetus in the occiput anterior position.