Stein Tore Nilsen

Risk factors and clinical manifestations of pre‐eclampsia

Objective To study associations between established risk factors for pre‐eclampsia and different clinical manifestations of the disease.

Size at birth and gestational age as predictors of adult height and weight

Background: Both birth length and birth weight are associated with height in adulthood and may have independent contributions to adult body size, but the effects of gestational age on these associations have not been fully evaluated. Our objective was to examine the independent contributions of gestational age, and of length and weight at birth, on adult (age 18 years) height and weight, with a special focus on the effects of being born preterm. Methods: In this nationwide cohort study, records of 348,706 male infants included in the Medical Birth Registry of Norway (1967–1979) were linked to the Norwegian Conscripts Service (1984–1999). Complete follow-up information, including deaths, emigration, and disability pension, was obtained for 94%. We analyzed length and weight at birth using standardized (z-scores) values and stratified by gestational age. Results: The positive association between birth length and adult height was stronger than between birth weight and adult weight (R2 = 7–9% compared with <0.1%, respectively). The strongest associations were seen among those born at gestational age 39 to 41 weeks. The effects of birth length on adult height, and of birth weight on adult weight, were considerably less among preterm births than among term births. Length and weight at birth each contributed independently to adult stature and body weight. The increase in adult weight per relative birth weight category was greatest for infants who were both heavy and long at birth. Conclusions: Birth length is perhaps a better predictor of adult height and weight than birth weight, and should be considered as a possible risk factor for adult morbidity and mortality.

Serum Urate as a Predictor of Fetal Outcome in Severe Pre‐Eclampsia

Abstract. Maternal serum urate levels were studied in 50 normal pregnancies and 72 cases of severe pre‐eclampsia. Markedly elevated levels of serum urate were found in severe pre‐eclampsia, compared with normal pregnancy. In severe pre‐eclampsia significantly higher levels were found prior to parturition in cases of growth retardation and perinatal distress, compared with patients whose newborns were of normal size and condition. Particularly high serum urate levels were found early in the third trimester in cases of perinatal death. A slight but significant correlation was found between the weight centile of the newborn and the last maternal urate level before parturition. A rapidly rising urate level reliably predicted perinatal distress. The last maternal serum urate before parturition was correlated with the hemoglobin and erythrocyte volume fraction values in the same blood sample.

Iron supplementation in pregnancy – evidence and controversies

Approximately 20% of women in industrialized countries have iron deficiency in pregnancy. This article focuses on the diagnostic problem of anemia and iron deficiency and discusses different strategies for iron supplementation in pregnancy. S‐ferritin is commonly used to diagnose empty iron stores and is considered useful early in pregnancy as a diagnostic tool. Mean cellular volume (MCV), s‐Fe and erythrocyte distribution width is too unspecific. Serum transferrin receptor (sTfR) is a relatively novel promising indicator of iron deficiency. Iron demands of the pregnant women are discussed as well as the dietary content of iron. Both beneficial and adverse effects of iron supplementation are outlined. It is not documented that supplementation has any substantial effect on birth weight or various complications in pregnancy. However, supplementation corrects the iron store and biochemical parameters of iron deficiency including hemoglobin concentration (Hb) and maintains the maternal iron stores in the puerperium. Recent literature also suggests that iron supply to the pregnant women may have beneficial effects on the iron content of neonates the first year of life.

Blood pressure in early adolescence in the offspring of preeclamptic and normotensive pregnancies

Objective To compare blood pressure (BP) in adolescence (11–12 years) among the offspring of preeclamptic and normotensive pregnancies. Method SBP and DBP of 181 girls and boys born after pregnancies with preeclampsia were measured and compared with the BP of 356 age-matched girls and boys of normotensive pregnancies. The association of preeclampsia with later BP was adjusted for perinatal information, anthropometric factors at follow-up, and maternal BP and BMI. Results In the preeclampsia group, SBP in early adolescence was higher than in the normotensive group (115.3 vs. 113.5 mmHg, P = 0.03), but there was no difference in DBP (66.4 vs. 65.3 mmHg, P = 0.10). After adjustment for maternal body mass and BP, the difference in SBP was largely attenuated. Conclusion The higher SBP among adolescent offspring of preeclamptic pregnancies could be mediated by maternal body mass or BP, factors that are positively associated with the risk of preeclampsia in pregnancy.

Relationship of insulin-like growth factor-I and insulin-like growth factor binding proteins in umbilical cord plasma to preeclampsia and infant birth weight

OBJECTIVE To determine whether preeclampsia influences insulin‐like growth factor‐I (IGF‐I), insulin‐like growth factor binding protein‐1 (IGFBP‐1), and insulin‐like growth factor binding protein‐3 (IGFBP‐3), independent of its effect on birth weight. METHODS Cord blood was collected in 12,804 consecutive deliveries. We identified 258 preeclamptic pregnancies that were subclassified as mild or severe and early or late. For comparison, 609 control pregnancies were selected. Fetal growth was expressed as the ratio between observed and expected birth weight, with adjustment for gestational age at birth. IGF‐I, IGFBP‐1, and IGFBP‐3 were measured in umbilical plasma. The contribution of preeclampsia and birth weight to each measured factor was assessed by multiple linear regression analyses. RESULTS Between mild preeclampsia and controls, there were no differences in IGF‐I, IGFBP‐1, and IGFBP‐3. In severe and early onset preeclampsia, umbilical cord plasma IGF‐I was approximately 50% lower, and IGFBP‐1 was more than twice as high as in controls (both P < .01). At each birth weight level, IGF‐I was lower and IGFBP‐1 was higher in severe or early preeclampsia than among controls of similar weight. Birth weight and preeclampsia were, independent of each other, associated with IGF‐I, whereas birth weight, but not preeclampsia, was associated with IGFBP‐1, after adjustment for gestational age. CONCLUSION Fetal growth restriction caused by severe or early preeclampsia is associated with lower umbilical levels of IGF‐I than low birth weight caused by other conditions. Preeclampsia may contribute to the observed IGF‐I reduction, either as part of the underlying causes of preeclampsia, or as a consequence of the disease.

Maternal Hemoglobin Concentration is Closely Related to Birth Weight in Normal Pregnancies

Abstract. Maternal Hb levels during the third trimester were studied in relation to certain maternal and fetal parameters in 877 apparently normal pregnancies. Low Hb levels at term were closely associated with increased frequency of newborns in the heavy weight‐for‐date group. Conversely, high maternal Hb levels were closely associated with an increased frequency of newborns in the light weight‐for‐date group. The maternal Hb levels both in the early third trimester and at term were significantly higher in mothers of small‐for‐date newborns than in those with newborns of normal weight. In both groups the maternal Hb levels increased significantly during the third trimester of pregnancy. High maternal Hb levels both early and late in the third trimester of pregnancy should be a matter of concern rather than of reassurance.

Males with Low Birthweight Examined at 18 Years of Age

ABSTRACT. An 18 years follow‐up study of 105 males born in 1962/63 with birthweight ≤ 2500 g was made at the military draft board examinations in 1981. The medical and psychological tests were compared to the tests of the total cohort of 35 728 Norwegian conscripts. The early neonatal mortality in the study was 15.2 %, and of those examined at 18 years of age was 6.7 % unfit for military service, compared to 6.2 % in the total cohort. Ten organ systems were analyzed, significantly increased frequency of unfitness being found only for the vision. Intelligence testing was done on 71 of the studied subjects, and the mean was the same as the national average. Children with weight‐for‐date centile < 10 at birth had the same general intelligence at 18 years as the national average. However, the weight and height at adult age were significantly correlated to the weight‐for‐date at birth. The study indicates that those low birthweight children who survived the neonatal period in the beginning of the nineteen‐sixties, were except for stature and minor defects of vision, indistinguishable from those of normal birthweight at the age of eighteen.

Smoking, hemoglobin levels, and birth weights in normal pregnancies

Of 811 otherwise healthy, nonanemic, pregnant Norwegian women, 43% smoked during the third trimester. No significant association existed between smoking habits and hemoglobin levels during the third trimester, but the fairly small number of heavy smokers (greater than 10 cigarettes per day) may have precluded the discovery of subtle true differences. Birth weights were transferred to a weight-for-dates percentile scale, based on the distribution of the total Norwegian birth population over an 11-year period. With a grouping in quartiles according to this scale, a strong correlation between smoking habits and low birth weights emerged, with 47% of newborn infants of heavy smokers falling in the lowest quartile. Levels of hemoglobin were inversely correlated to birth weight quartiles, equally in mothers who smoked and those who did not smoke. However, when birth weights were grouped according to maternal hemoglobin at term, the tobacco-related effect on birth weight appeared only with levels of hemoglobin above 12 gm/dl, being particularly strong for levels above 13 gm/dl. Hemoglobin levels of 9.0 to 11.9 gm/dl appeared to protect from growth retardation the fetuses of nonanemic mothers who smoked. Studying ponderal, or weight-by-length, indices, we found that growth-retarded babies of mothers who smoked tended to be thin, thus indicating that they had been deprived of nutrients.

Boys Born by Forceps and Vacuum Extraction Examined at 18 Years of Age

Abstract. An 18‐year follow‐up study was made of 62 males delivered by forceps and 38 by vacuum extraction in 1962‐63. The obstetrical data are compared with the medical and psychological military draft board examinations. The mortality and morbidity rates were not significantly different from those of the total cohort of Norwegian conscripts, either in the forceps or in the vacuum group. Rotation of the fetal head with Kiellands forceps in midcavity extractions did not adversely affect the late results. A significantly elevated mean intelligence score was found in the forceps group, while the vacuum group did not differ from the national average.