A prospective study of the transient decrease in ovarian cancer risk following childbirth

Epidemiologic evidence shows that the risk of ovarian cancer is decreased following childbirth. We examined the time points when the decreased risk of postpartum maternal ovarian cancer reaches the lowest point and whether the protective effect diminishes over time. A case-control study nested within the Swedish Fertility Register included 10,086 cases of epithelial ovarian cancer recorded in the Swedish Cancer Register from 1961 to 2001. From the Fertility Register, 49,249 eligible subjects matched to the cases by age were selected as controls. The analysis contrasted risk between adjacent parities through logistic regression models that included indicator variables representing each year of age, age at delivery, and time since delivery. Compared with nulliparous women, uniparous women had a transient decrease in maternal ovarian cancer risk at 2 years after delivery (spline-derived odds ratio, 0.71; 95% confidence interval, 0.53-0.95, for those delivered at age 25 years) and maintained a lower risk for 4 years postpartum. Similar transient decreases were observed in biparous women compared with uniparous women and in women with three parities compared with biparous women. The protective effect of childbearing seemed to diminish with time. The transient decrease in postpartum ovarian cancer risk may define the latent period required for pregnancy hormones in clearing out ovarian cells that have undergone early stages of malignant transformation. The period before the risk increases again could indicate the period required for ovarian cancer induction

Hyperemesis gravidarum and subsequent breast cancer risk

Both parity and a young age at first pregnancy are associated with a reduction in breast cancer risk. The hormones involved in this process are not fully investigated. Human chorionic gonadotropin is a placental hormone, which in rats and in human breast cells in vitro has been shown to prevent against breast cancer. Hyperemesis, a severe nausea combined with vomiting during pregnancy, is associated with increased levels of human chorionic gonadotropin. We investigated the possible relationship between hyperemesis and subsequent breast cancer risk in a case–control study based on registry data. Among 13 079 breast cancer cases and 34 348 individually matched controls we found 148 cases and 405 controls who had been hospitalised for hyperemesis. Hyperemesis was not associated with breast cancer risk (adjusted odds ratio 1.05, 95% confidence interval 0.86–1.27), and similar risks were observed regardless of age at diagnosis, number of hospitalisations for hyperemesis or time of follow-up. Our results do not support the hypothesis that human chorionic gonadotropin is responsible for the protective effect of pregnancies upon breast cancer risk

Obstetric and Perinatal Outcomes in Type 1 Diabetic Pregnancies: A large, population-based study

The aim of this epidemiological study was to elucidate whether in recent years, obstetric and perinatal outcomes in pregnancies complicated by type 1 diabetes (T1DM) have improved or not. The objective was also to identify possible risk factors for adverse outcome for the mother, fetus and the newborn. All studies (Ι-ΙV) included in this thesis were based on national data from the Swedish Medical Birth Registry, during the time period 1991-2007. In 5,089 type 1 diabetic pregnancies and 1.2 million controls we found significantly increased risks of all adverse outcomes in women with T1DM: adjusted odds ratios: severe preeclampsia: 4.47 (3.77-5.31), Caesarean delivery: 5.31 (4.97-5.69), stillbirth: 3.34 (2.46- 4.55), perinatal mortality: 3.29 (2.50-4.33), major malformations: 2.50 (2.13-2.94) and large for gestational age: LGA (birth weight ≥ +2 SD): 11.45 (10.61-12.36) (study Ι). The markedly elevated odds of an LGA outcome inspired us to characterize in more detail the distribution of birth size in a large national cohort of T1DM offspring (study ΙΙ n=3,705) and to investigate if disproportionate body composition was associated with increased risk of perinatal complications (study ΙΙΙ n=3,517). Percentiles for birth weight (BW), birth length (BL) and head circumference (HC) were formed based on data from non-diabetic pregnancies and standard deviation scores (SDS) were calculated for BW, BL and HC. The ponderal index (PI: BW in grams/(BL in cm) ³ was used as a proxy for body proportionality and fat mass and we defined disproportionate/overweight LGA as infants with a BW and PI ≥90th percentile for gestational age and gender. The distributions of BW, BL and HC were all unimodal but significantly shifted to the right of the normal reference. The distribution for BW was most markedly shifted to the right. 47% were LGA with a BW ≥90th adjusted percentile. The mean ponderal index (PI) was significantly increased and 46% of LGA infants were disproportionate with a PI ≥90th percentile and thus overweight at birth. A novel and unexpected finding was that fetal macrosomia was more pronounced in preterm and female infants (study ΙΙ). Surprisingly, neonatal outcome was independent of body proportionality in appropriate for gestational age (AGA) and LGA infants. The risk of adverse outcome was significantly increased in LGA compared with AGA infants born at term (study ΙΙΙ). There was a significant interaction between gestational age and body weight with prematurity overriding LGA as a risk factor for neonatal morbidity in moderately preterm infants. In study ΙV, we examined the risk of adverse outcome in relation to pre-pregnancy body mass index in a national cohort of 3,457 T1DM pregnancies compared to 764,498 non-diabetic pregnancies. Maternal overweight/obesity increases the risk of adverse outcome in both women with and without T1DM. Within the T1DM cohort, obesity was associated with increased odds of major malformations adjusted OR: 1.77 (1.18-2.65) and preeclampsia adjusted OR: 1.74 (1.35-2.25). T1DM was a significant effect modifier of the association between BMI and major malformations, preeclampsia, LGA and neonatal overweight. Conclusion: In spite of major improvements in the management of type 1 diabetic pregnancies over the years, the present findings clearly demonstrate that T1DM pregnancies still are associated with significantly increased risk of adverse outcomes. An important observation is the rising incidence of LGA infants, which partly can be attributed to a concomitant increase in maternal BMI. This development is worrying as LGA infants face an excess risk of both perinatal and future complications as compared to normal sized infants. The novel and unexpected finding of a gender difference in fetal macrosomia requires further investigations

Maternal age, education level and migration: Socioeconomic determinants for smoking during pregnancy in a field study from Turkey

WOS: 000279909900003PubMed ID: 20534133Background: Smoking during pregnancy has been associated with socioeconomic determinants and it is recognized as the most important preventable risk factor for an unsuccessful pregnancy outcome. Turkey has national data on the prevalance of smoking during pregnancy; however there is no data on the characteristics of the high-risk population. This is a field study that aims to identify socioeconomic determinants for smoking during pregnancy as well as differentiating the daily and occasional smokers. Method: Cross sectional study was conducted among women with 0-5 year old children living in the area served by Primary Health Care Center (PHCC) in Burhaniye, Turkey. Face-to-face interviews were conducted by the researchers during January-March 2008 at the home of the participants with 83.7% response rate (n = 256). The relation of "smoking during pregnacy" and "daily smoking during pregnancy" with the independent variables was determined with chi(2) tests. Women's age, educational level, number of previous births, place of origin, migration, partner's educational level, poverty, perceived income, social class were evaluated. Statistical significance was achieved when the p value was less than 0.05. The variables in relation with the dependent variables in the chi(2) tests were included in the forward-stepwise logistic analysis. Results: Prevalance of smoking during pregnancy was 22.7%. The majority (74.1%) were daily smokers. Young mothers (< 20), low educated women and migrants were at increased risk for smoking during pregnancy. Low education and being a migrant were risk factors for daily consumption (p < 0.05). Conclusions: Systematic attention should be paid to socioeconomic determinants in smoking for pregnant women, especially in countries like Turkey with high rates of infant and mother mortality and substantial health inequalities. Young mothers (< 20), low educated women and migrants are important groups to focus on

Prenatal X-ray exposure and childhood brain tumours: a population-based case–control study on tumour subtypes

We investigated childhood brain tumours by histological subtype in relation to prenatal X-ray among all children, less than 15 years of age, born in Sweden between 1975 and 1984. For each case, one control was randomly selected from the Medical Birth Register, and exposure data on prenatal X-ray were extracted blindly from antenatal medical records. Additional information on maternal reproductive history was obtained from the Medical Birth Register. We found no overall increased risk for childhood brain tumour after prenatal abdominal X-ray exposure (adjusted odds ratio (OR): 1.02, 95% confidence interval (CI): 0.64–1.62); primitive neuroectodermal tumours had the highest risk estimate (OR: 1.88, 95% CI: 0.92–3.83)

Continuous growth reference from 24th week of gestation to 24 months by gender

<p>Abstract</p> <p>Background</p> <p>Growth charts and child growth assessment have become prime global instruments in child health practice over the 30 years. An updated, continuous growth standard that bridges size at birth values with postnatal growth values can improve child growth screening and monitoring.</p> <p>Methods</p> <p>This novel growth chart was constructed from two sources of information. Size at birth (weight, length and head circumference) reference values were updated based on information of normal deliveries (i.e. singleton live births without severe congenital malformation, with healthy mothers and born vaginally) from the Swedish Medical Birth Registry, 1990–1999 (n = 810393). Weight was evaluated using logarithmic transformation as for postnatal weight. Standard deviations were estimated from data within the empirical mean ± 1.0 SD for each gestational week and gender. These values were smoothed by empirical curve-fitting together with values from our recently published postnatal growth reference including 3650 longitudinally followed children from birth to final height <abbrgrp><abbr bid="B9">9</abbr></abbrgrp>. Timescale and weight axes were made logarithmic in order to magnify the early time part of the graph.</p> <p>Results</p> <p>This study presents the first continuous gender specific growth chart from birth irrespective of gestational age at birth until 2 years of age for weight, length and head circumference. Birth weight at 40 weeks of gestation increased approximately 100 gram and length increased only 1 mm compared with earlier Swedish reference from 1977–81. The curve is now less S-shaped as compared with earlier curves and compared with 4 curves from other countries and with more constant variation over the whole range.</p> <p>Conclusion</p> <p>Our values picture the unrestricted pattern of growth improving the detection of a deviating growth pattern, when the growth of an individual infant is plotted on the charts. Especially for very preterm infants age corrected growth can be more easily evaluated although it must be recognized that the early comparison is with what is estimated as normal growth in uterus. The reference values are useful in child health care systems for population screening, but also in research or in the clinic for evaluating various growth promoting interventions – either nutritional, surgical or therapeutic – that might affect a child in early life.</p

Evidence of space–time clustering of childhood acute lymphoblastic leukaemia in Sweden

We have examined 645 recorded cases of childhood acute lymphatic leukaemia (ALL) in Sweden during 1973–89 to identify space–time clustering by using the close-pair method of Knox. The records included date of birth and of diagnosis as well as addresses at birth and at diagnosis. There was a significant excess of case pairs close in date of birth and place of birth in the 5- to 15-year age group. © 1999 Cancer Research Campaig

The risk factors for unexplained antepartum stillbirths in Scotland, 1994 to 2003

Objective: To determine the factors contributing to unexplained antepartum stillbirth in Scotland. Study Design: A 10-year birth database in Scotland was used to compare the unexplained antepartum stillbirth with other birth outcomes. The sample unit was a pregnant mother with a gestational age of 20 weeks and above and with a fetal birth weight of 200 g and above. Result: Maternal age of 35 years and above, lower deprivation category, inaccessible area of residence, maternal smoking, maternal height of <160 cm and gestational age of above 39 weeks were significantly associated with unexplained antepartum stillbirth. In multivariable analysis only maternal age (adjusted odds ratio (OR): 1.8, confidence interval (CI): 1.1 to 3.0, P=0.02), smoking during pregnancy (adjusted OR: 2.0, CI: 1.1 to 3.5, P=0.02), and maternal height (adjusted OR: 1.4, CI: 1.1 to 1.8, P=0.01), remain significant. Screening of pregnancies based on these three risk factors had 4.2% sensitivity and 99.4% specificity. The prevalence of stillbirth for this population was 0.2%. A positive predictive value of only 1.2% implies that only 1 in 83 women with these three risk factors will have antepartum stillbirth. The remaining 82 will suffer needless anxiety and potentially diagnostic procedures. Conclusion: Advanced maternal age, maternal smoking, and shorter maternal height were associated risk for unexplained antepartum stillbirth but screening based on these factors would be of limited value

Birth characteristics and risk of colorectal cancer: a study among Swedish twins

Type-2 diabetes increases the risk of colorectal cancer, and is also associated with low birth weight. However, we found no evidence of associations between birth characteristics and risk of colorectal cancer (m=248) among Swedish twins