Pre-eclampsia and childhood asthma

Studies of pre-eclampsia and childhood asthma are conflicting, and none have performed a formal mediation analysis of preterm birth.We examined the association between pre-eclampsia and asthma at 7 years using national registries, including all births in Norway from 1999 to 2006 (n=406 907), and a subsample of children in the Norwegian Mother and Child Cohort Study (MoBa) (n=45 028) using log-linear regression. We performed a mediation analysis of preterm birth, and a sibling comparison to evaluate unobserved confounding.There was a positive association between pre-eclampsia and asthma in the registry study, with an adjusted relative risk of 1.31 (95% CI 1.22–1.41), but not in MoBa, which had an adjusted relative risk of 1.19 (95% CI 0.99–1.44). The odds ratios for the direct effect not mediated through preterm birth and the indirect effect in the registry linkage were 1.19 (95% CI 1.10–1.29) and 1.12 (95% CI 1.11–1.14), respectively. The sibling comparison indicated no association between pre-eclampsia and asthma (adjusted OR 1.07, 95% CI 0.87–1.33).In this large study, which used different datasets and analytic approaches, there was little evidence for an association between pre-eclampsia and childhood asthma. The association was weak and largely explained by pre-term birth and confounders shared by siblings.</jats:p

Prediction of gestational age based on genome-wide differentially methylated regions

BACKGROUND: We explored the association between gestational age and cord blood DNA methylation at birth and whether DNA methylation could be effective in predicting gestational age due to limitations with the presently used methods. We used data from the Norwegian Mother and Child Birth Cohort study (MoBa) with Illumina HumanMethylation450 data measured for 1753 newborns in two batches: MoBa 1, n = 1068; and MoBa 2, n = 685. Gestational age was computed using both ultrasound and the last menstrual period. We evaluated associations between DNA methylation and gestational age and developed a statistical model for predicting gestational age using MoBa 1 for training and MoBa 2 for predictions. The prediction model was additionally used to compare ultrasound and last menstrual period-based gestational age predictions. Furthermore, both CpGs and associated genes detected in the training models were compared to those detected in a published prediction model for chronological age. RESULTS: There were 5474 CpGs associated with ultrasound gestational age after adjustment for a set of covariates, including estimated cell type proportions, and Bonferroni-correction for multiple testing. Our model predicted ultrasound gestational age more accurately than it predicted last menstrual period gestational age. CONCLUSIONS: DNA methylation at birth appears to be a good predictor of gestational age. Ultrasound gestational age is more strongly associated with methylation than last menstrual period gestational age. The CpGs linked with our gestational age prediction model, and their associated genes, differed substantially from the corresponding CpGs and genes associated with a chronological age prediction model. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13059-016-1063-4) contains supplementary material, which is available to authorized users

Association between interpregnancy interval and adverse birth outcomes in women with a previous stillbirth:an international cohort study

Background: WHO recommends that women wait at least 2 years after a livebirth and at least 6 months after a miscarriage or induced abortion before conceiving again, to reduce the risk of adverse birth outcomes in the subsequent pregnancy. No recommendation exists for the optimal interval after a stillbirth. We investigated the association between interpregnancy interval after stillbirth and birth outcomes in the subsequent pregnancy. Methods: In this international cohort study, we used data from birth records from Finland (1987–2016), Norway (1980–2015), and Western Australia (1980–2015). Consecutive singleton pregnancies in women whose most recent pregnancy had ended in stillbirth of at least 22 weeks' gestation were included in the analysis. Interpregnancy interval was defined as the time between the end of pregnancy (delivery date) and the start of the next pregnancy (delivery date of next pregnancy minus gestational age at birth). We calculated odds ratios (ORs) for stillbirth, preterm birth, and small-for-gestational-age birth by interpregnancy interval by country, adjusted for maternal age, parity, decade of delivery, and gestational length of the previous pregnancy. A fixed-effects meta-analysis was used to estimate pooled ORs. Findings: We identified 14 452 births in women who had a stillbirth in the previous pregnancy; median interpregnancy interval after stillbirth was 9 months (IQR 4–19). 9109 (63%) women conceived within 12 months of the stillbirth. Of the 14 452 births, 228 (2%) were stillbirths, 2532 (18%) were preterm births, and 1284 (9%) were small-for-gestational-age births. Compared with an interpregnancy interval of 24–59 months, intervals shorter than 12 months were not associated with increased odds of subsequent stillbirth (pooled adjusted OR 1·09 [95% CI 0·63–1·91] for <6 months; 0·90 [0·47–1·71] for 6–11 months), preterm birth (0·91 [0·75–1·11] for <6 months; 0·91 [0·74–1·11] for 6–11 months), or small-for-gestational-age birth (0·66 [0·51–0·85] for <6 months; 0·64 [0·48–0·84] for 6–11 months). Further, we noted no difference in the association between interpregnancy interval and birth outcomes by gestational length of the previous stillbirth. Interpretation: Conception within 12 months of a stillbirth was common and was not associated with increased risk of adverse outcomes in the subsequent pregnancy. These findings could be used when counselling women who are planning future pregnancies after a stillbirth and for informing future recommendations for pregnancy spacing in a high-income setting. Funding: National Health and Medical Research Council (Australia), and Research Council of Norway

Maternal pre-pregnancy BMI and reproductive health in adult sons : a study in the Danish National Birth Cohort

STUDY QUESTION: Is maternal pre-pregnancy BMI associated with semen quality, testes volume, and reproductive hormone levels in sons? SUMMARY ANSWER: Maternal pre-pregnancy BMI was associated with an altered reproductive hormone profile in young adult sons, characterized by higher levels of oestradiol, LH, and free androgen index (FAI) and lower levels of sex hormone-binding globulin (SHBG) in sons born of mothers with pre-pregnancy overweight and obesity. WHAT IS KNOWN ALREADY: Evidence suggests that maternal pre-pregnancy BMI may influence reproductive health later in life. Only one pilot study has investigated the association between maternal pre-pregnancy BMI and reproductive health outcomes in sons, suggesting that a high BMI was associated with impaired reproductive function in the adult sons. STUDY DESIGN, SIZE, DURATION: A population-based follow-up study of 1058 young men from the Fetal Programming of Semen Quality (FEPOS) cohort nested within the Danish National Birth Cohort (DNBC), 1998–2019, was carried out. PARTICIPANTS/MATERIALS, SETTING, METHODS: In total, 1058 adult sons (median age 19 years, 2months), born 1998–2000 by mothers included in the DNBC, participated in FEPOS. At a clinical examination, they provided a semen and blood sample, measured their testes volume, and had height and weight measured. Maternal pre-pregnancy BMI was obtained by self-report in early pregnancy. Semen characteristics, testes volume, and reproductive hormone levels were analysed according to maternal pre-pregnancy BMI categories and as restricted cubic splines using negative binomial and ordinary least square regression models. Mediation analyses examined potential mediation by the sons’ birthweight, pubertal timing, fat mass, and BMI. Additional analyses investigated the role of paternal BMI in the potential associations between maternal BMI and reproductive health outcomes. MAIN RESULTS AND THE ROLE OF CHANCE: We found no consistent associations between maternal pre-pregnancy BMI and semen characteristics or testes volume. Sons of mothers with higher pre-pregnancy BMI had higher oestradiol and lower SHBG levels, both in a dose-dependent manner. Sons of mothers with pre-pregnancy obesity (30 kg/m2) had higher LH levels and a higher FAI than sons born by mothers with normal pre-pregnancy BMI (18.5–24.9 kg/m2 ). The mediation analyses suggested that the effect of maternal pre-pregnancy BMI on higher levels of oestrogen, LH, and FAI was partly mediated by the sons’ birthweight, in addition to adult fat mass and BMI measured at the clinical examination, whereas most of the effect on lower levels of SHBG was primarily mediated by the sons’ own fat mass and BMI. Paternal BMI was not a strong confounder of the associations in this study. LIMITATIONS, REASONS FOR CAUTION: This study was based in a population-based cohort with a low prevalence of overweight and obesity in both mothers and adult sons. Some men (10%) had blood for reproductive hormone assessment drawn in the evening. While several potential confounding factors were accounted for, this study's inherent risk of residual and unmeasured confounding precludes provision of causal estimates. Therefore, caution should be given when interpreting the causal effect of maternal BMI on sons’ reproductive health. WIDER IMPLICATIONS OF THE FINDINGS: Given the widespread occurrence of overweight and obesity among pregnant women, it is imperative to thoroughly examine the potential consequences for reproductive hormone levels in adult sons. The potential effects of maternal pre-pregnancy obesity on sons’ reproductive hormone profile may potentially be partly avoided by the prevention of overweight and obesity in the sons.Peer reviewe

Viny weeds of the Eastern Caribbean

There are at least forty-two viny weed species found in the Eastern Caribbean, belonging to twelve botanical families. The Convolvulaceae has fifteen species from five genera, and the Fabaceae has twelve species from ten genera. These viny weeds are known by a variety of vernacular names, though two, including a very striking common weed, appear to have no recognized and accepted names. A simple key is presented, but it does not claim to be inclusive of all viny species. Simple brief descriptions are given