Maternal size at birth and the development of hypertension during pregnancy: a test of the Barker hypothesis.

BACKGROUND: Whether individuals who were small at birth are at increased risk of developing cardiovascular disease (the Barker hypothesis) is a topic of great controversy. Although an increased risk has been suggested by several reports, the reports have been criticized for being based on ill-defined populations, for the large numbers of subjects who were unavailable for follow-up, and for inadequate control of socioeconomic status. OBJECTIVE: To determine whether a woman's weight and gestational age at birth predict the development of hypertension during her subsequent pregnancies. DESIGN: Prospective observational study. SUBJECTS: Women born in Copenhagen, Denmark, as subjects in the Danish Perinatal Study (1959-1961) were traced through the Danish Population Register. Information was obtained on their pregnancies from 1974 to 1989. MAIN OUTCOME MEASURES: Onset of hypertension in pregnancy, defined by the presence of a systolic blood pressure of 140 mm Hg or greater or a diastolic blood pressure of 90 mm Hg or greater on 2 visits at or after 140 days' gestation. RESULTS: Hypertension developed in 11.3% of the pregnant women who were small for gestational age at birth, compared with 7.2% of the pregnant women who were not small for gestational age at birth (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.1-2.6), and in 9.4% of the pregnancies in women who were preterm at birth, compared with 7.6% of pregnancies in women who were not preterm at birth (OR, 1.3; 95% CI, 0.8-2.0). After adjustment for adult body mass index, smoking, birth order, and hypertension in the subjects' own mothers, the ORs for small-for-gestational-age women and preterm women to develop hypertension during pregnancy were 1.8 (95% CI, 1.1-2.8) and 1.5 (95% CI, 0.96-2.5), respectively. CONCLUSION: These results support the Barker hypothesis, while addressing many of the methodological criticisms of previous investigations.

Father's effect on infant birth weight.

OBJECTIVE: We sought to determine whether paternal size at birth and during young adulthood influences the birth weight of the offspring. STUDY DESIGN: This historic cohort study followed up girls born in Copenhagen during 1959 to 1961. Their pregnancies in 1974 to 1989 were traced through the Danish Population Register, and the Personal Identification Numbers of the fathers of the children were obtained. Paternal birth weight was obtained from midwifery records and adult stature from military draft records. RESULTS: Compared with fathers who weighed at least 4 kg at birth, fathers who weighed 3 to 3.99 kg at birth had infants who were 109 gm lighter, and fathers who weighed <3 kg had infants who were 176 gm lighter after adjustment for maternal birth weight and adult stature, smoking, and medical and socioeconomic factors. After adjustment, fathers in the lowest quartile of adult body mass index had infants that were 105 gm lighter than those of fathers in the highest quartile. Both paternal birth weight and adult body mass index exhibited significant trends in association with infant birth weight. CONCLUSION: Independently of maternal size, the father's physical stature, particularly his own size at birth, influences the birth weight of his children.

Preterm and small-for-gestational-age birth across generations.

OBJECTIVE: Our purpose was to determine whether women who were themselves small for gestational age at birth are at risk of giving birth to a small-for-gestational-age child and whether women who were themselves preterm at birth are at risk for preterm delivery. STUDY DESIGN: Women born in Copenhagen as subjects in the Danish Perinatal Study (1959 to 1961) were traced through the Danish Population Register. Information was obtained on their pregnancies during 1974 through 1989. RESULTS: A total of 25% of the children of small-for-gestational-age women were small for gestational age compared with 11% of the children of non-small-for-gestational-age women. Eleven percent of the children of preterm women were preterm compared with 7% of the children of women born at term. The adjusted odds ratios were 2.0 (95% confidence interval 1.4 to 3.0) for women who were small for gestational age to have small-for-gestational-age children and 1.5 (95% confidence interval 0.9 to 2.5) for women who were born preterm to have preterm children. Small-for-gestational-age women were not at significantly increased risk of preterm delivery (odds ratio 1.2), and preterm women were not at significantly increased risk of having small-for-gestational-age children (odds ratio 1.3). CONCLUSIONS: Reduced intrauterine growth of the mother is a risk factor for reduced intrauterine growth of her children. However, preterm birth of the mother is not strongly associated with preterm birth of her children.

Delivery of preterm and small for gestational age infants across generations.

Two generations of women were studied to clarify the influence of a woman's own preterm delivery or intrauterine growth retardation on her later risk of delivering preterm or growth-retarded infants. The first generation consists of the cohort of women who gave birth at the National University Hospital (Rigshospitalet) in Copenhagen from 1959 to 1961 and the second, those of their daughters that have delivered themselves. The background of the study and the procedures involved are described. The percentage of data obtained and the preliminary findings concerning the relationship between social and demographic factors and the willingness of subjects to participate are included.

Second generation follow-up of the Danish perinatal study women: study design and factors affecting response.

To study the mother-infant correlation of fetal growth and duration of pregnancy, women who were born as subjects in the Danish Perinatal Study (1959-61) were traced and interviewed, and the pregnancy and birth records of their children were abstracted. The study population consisted of 159 women who were small-for-gestational age (SGA) at birth, 162 who were preterm, 38 who were both preterm and SGA, and 939 term, appropriately-grown control women. Methods for sample selection, measuring gestational age and fetal growth in both generations, locating and interviewing the women, abstracting the records of their children, and obtaining paternal birth and adult stature are described. A total of 84.5% of the selected women were successfully interviewed; the fraction interviewed did not differ by maternal birth status. The medical records of over 98% of pregnancies to the study women were abstracted, making it possible to study various factors associated with completion of an interview. By a variety of measures, women of higher socio-economic status were more likely to be interviewed. Birthweight and adult weights were available for 63 and 73% of the children's fathers.

Polyvinyl chloride dermatitis not caused by phthalates.

Seven cases of contact dermatitis in children due to identification bracelets made of polyvinyl chloride plastic are reported. Patch tests with the bracelets were negative in the five cases tested. It is concluded that the reactions were irritant due to some unknown chemical in the bracelets. The most widely used plasticizers in PVC, phthalates, must have very low sensitizing properties, as only one positive patch test was found in 1532 patch tests with phthalate mix, performed as a joint study by the International Contact Dermatitis Research Group.