Risk of adverse pregnancy outcomes in twin- and singleton-born women: An inter-generational cohort study.

OBJECTIVE: To compare the risk of adverse pregnancy outcomes between twin-born and singleton-born women. We also evaluated whether in utero exposure to pre-eclampsia or preterm delivery affected adverse pregnancy outcomes in women's own pregnancies. DESIGN: Population-based cohort study. SETTING: Medical Birth Registry of Norway 1967-2020. POPULATION: 9184 twin-born and 492 894 singleton-born women during 1967-2005, with their later pregnancies registered during 1981-2020. METHODS: Data from an individual's birth were linked to their later pregnancies. We used generalised linear models with log link binomial distribution to obtain exponentiated regression coefficients that estimated relative risks (RRs) with 95% confidence intervals (CIs) for associations between twin- or singleton-born women and later adverse pregnancy outcomes. MAIN OUTCOME MEASURES: Pre-eclampsia, preterm delivery or perinatal loss in twin-born compared with singleton-born women. RESULTS: There was no increased risk for adverse outcomes in twin-born compared with singleton-born women: adjusted RRs for pre-eclampsia were 1.00 (95% CI 0.93-1.09), for preterm delivery 0.96 (95% CI 0.90-1.02) and for perinatal loss 1.00 (95% CI 0.84-1.18). Compared with singleton-born women exposed to pre-eclampsia in utero, twin-born women exposed to pre-eclampsia had lower risk of adverse outcomes in their own pregnancies; the aRR for pre-eclampsia was 0.73 (95% CI 0.58-0.91) and for preterm delivery was 0.71 (95% CI 0.56-0.90). Compared with preterm singleton-born women, preterm twin-born women did not differ in terms of risk of pre-eclampsia (aRR 1.05, 95% CI 0.92-1.21) or perinatal loss (aRR 0.99, 95% CI 0.71-1.37) and had reduced risk of preterm delivery (RR 0.83, 95% CI 0.74-0.94). CONCLUSIONS: Twin-born women did not differ from singleton-born women in terms of risk of adverse pregnancy outcomes. Twin-born women exposed to pre-eclampsia in utero, had a lower risk of pre-eclampsia and preterm delivery compared with singleton-born women exposed to pre-eclampsia.

Long-term cardiovascular mortality in women with twin pregnancies by lifetime reproductive history.

BACKGROUND: Women with one lifetime singleton pregnancy have increased risk of cardiovascular disease (CVD) mortality compared with women who continue reproduction particularly if the pregnancy had complications. Women with twins have higher risk of pregnancy complications, but CVD mortality risk in women with twin pregnancies has not been fully described. OBJECTIVES: We estimated risk of long-term CVD mortality in women with naturally conceived twins compared to women with singleton pregnancies, accounting for lifetime number of pregnancies and pregnancy complications. METHODS: Using linked data from the Medical Birth Registry of Norway and the Norwegian Cause of Death Registry, we identified 974,892 women with first pregnancy registered between 1967 and 2013, followed to 2020. Adjusted hazard ratios (aHR) with 95% confidence intervals (CI) for maternal CVD mortality were estimated by Cox regression for various reproductive history (exposure categories): (1) Only one twin pregnancy, (2) Only one singleton pregnancy, (3) Only two singleton pregnancies, (4) A first twin pregnancy and continued reproduction, (5) A first singleton pregnancy and twins in later reproduction and (6) Three singleton pregnancies (the referent group). Exposure categories were also stratified by pregnancy complications (pre-eclampsia, preterm delivery or perinatal loss). RESULTS: Women with one lifetime pregnancy, twin or singleton, had increased risk of CVD mortality (adjusted hazard [HR] 1.72, 95% confidence interval [CI] 1.21, 2.43 and aHR 1.92, 95% CI 1.78, 2.07, respectively), compared with the referent of three singleton pregnancies. The hazard ratios for CVD mortality among women with one lifetime pregnancy with any complication were 2.36 (95% CI 1.49, 3.71) and 3.56 (95% CI 3.12, 4.06) for twins and singletons, respectively. CONCLUSIONS: Women with only one pregnancy, twin or singleton, had increased long-term CVD mortality, however highest in women with singletons. In addition, twin mothers who continued reproduction had similar CVD mortality compared to women with three singleton pregnancies.

Birthweight of the subsequent singleton pregnancy following a first twin or singleton pregnancy.

INTRODUCTION: Birthweight is an important pregnancy indicator strongly associated with infant, child, and later adult life health. Previous studies have found that second-born babies are, on average, heavier than first-born babies, indicating an independent effect of parity on birthweight. Existing data are mostly based on singleton pregnancies and do not consider higher order pregnancies. We aimed to compare birthweight in singleton pregnancies following a first twin pregnancy relative to a first singleton pregnancy. MATERIAL AND METHODS: This was a prospective registry-based cohort study using maternally linked offspring with first and subsequent pregnancies registered in the Medical Birth Registry of Norway between 1967 and 2020. We studied offspring birthweights of 778 975 women, of which 4849 had twins and 774 126 had singletons in their first pregnancy. Associations between twin or singleton status of the first pregnancy and birthweight (grams) in subsequent singleton pregnancies were evaluated by linear regression adjusted for maternal age at first delivery, year of first pregnancy, maternal education, and country of birth. We used plots to visualize the distribution of birthweight in the first and subsequent pregnancies. RESULTS: Mean combined birthweight of first-born twins was more than 1000 g larger than mean birthweight of first-born singletons. When comparing mean birthweight of a subsequent singleton baby following first-born twins with those following first-born singletons, the adjusted difference was just 21 g (95% confidence interval 5-37 g). CONCLUSIONS: Birthweights of the subsequent singleton baby were similar for women with a first twin or a first singleton pregnancy. Although first twin pregnancies contribute a greater combined total offspring birthweight including more extensive uterine expansion, this does not explain the general parity effect seen in birthweight. The physiological reasons for increased birthweight with parity remain to be established.

Interventions to prevent injuries in construction workers.

BACKGROUND: Construction workers are frequently exposed to various types of injury-inducing hazards. There are a number of injury prevention interventions, yet their effectiveness is uncertain. OBJECTIVES: To assess the effects of interventions for preventing injuries in construction workers. SEARCH METHODS: We searched the Cochrane Injuries Group's specialised register, CENTRAL (issue 3), MEDLINE, Embase and PsycINFO up to April 2017. The searches were not restricted by language or publication status. We also handsearched the reference lists of relevant papers and reviews. SELECTION CRITERIA: Randomised controlled trials, controlled before-after (CBA) studies and interrupted time-series (ITS) of all types of interventions for preventing fatal and non-fatal injuries among workers at construction sites. DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies, extracted data and assessed their risk of bias. For ITS studies, we re-analysed the studies and used an initial effect, measured as the change in injury rate in the year after the intervention, as well as a sustained effect, measured as the change in time trend before and after the intervention. MAIN RESULTS: Seventeen studies (14 ITS and 3 CBA studies) met the inclusion criteria in this updated version of the review. The ITS studies evaluated the effects of: introducing or changing regulations that laid down safety and health requirements for the construction sites (nine studies), a safety campaign (two studies), a drug-free workplace programme (one study), a training programme (one study), and safety inspections (one study) on fatal and non-fatal occupational injuries. One CBA study evaluated the introduction of occupational health services such as risk assessment and health surveillance, one evaluated a training programme and one evaluated the effect of a subsidy for upgrading to safer scaffoldings. The overall risk of bias of most of the included studies was high, as it was uncertain for the ITS studies whether the intervention was independent from other changes and thus could be regarded as the main reason of change in the outcome. Therefore, we rated the quality of the evidence as very low for all comparisons.Compulsory interventionsRegulatory interventions at national or branch level may or may not have an initial effect (effect size (ES) of -0.33; 95% confidence interval (CI) -2.08 to 1.41) and may or may not have a sustained effect (ES -0.03; 95% CI -0.30 to 0.24) on fatal and non-fatal injuries (9 ITS studies) due to highly inconsistent results (I² = 98%). Inspections may or may not have an effect on non-fatal injuries (ES 0.07; 95% CI -2.83 to 2.97; 1 ITS study).Educational interventionsSafety training interventions may result in no significant reduction of non-fatal injuries (1 ITS study and 1 CBA study).Informational interventionsWe found no studies that had evaluated informational interventions alone such as campaigns for risk communication.Persuasive interventionsWe found no studies that had evaluated persuasive interventions alone such as peer feedback on workplace actions to increase acceptance of safe working methods.Facilitative interventionsMonetary subsidies to companies may lead to a greater decrease in non-fatal injuries from falls to a lower level than no subsidies (risk ratio (RR) at follow-up: 0.93; 95% CI 0.30 to 2.91 from RR 3.89 at baseline; 1 CBA study).Multifaceted interventionsA safety campaign intervention may result in an initial (ES -1.82; 95% CI -2.90 to -0.74) and sustained (ES -1.30; 95% CI -1.79 to -0.81) decrease in injuries at the company level (1 ITS study), but not at the regional level (1 ITS study). A multifaceted drug-free workplace programme at the company level may reduce non-fatal injuries in the year following implementation by -7.6 per 100 person-years (95% CI -11.2 to -4.0) and in the years thereafter by -2.0 per 100 person-years (95% CI -3.5 to -0.5) (1 ITS study). Introducing occupational health services may result in no decrease in fatal or non-fatal injuries (one CBA study). AUTHORS' CONCLUSIONS: The vast majority of interventions to adopt safety measures recommended by standard texts on safety, consultants and safety courses have not been adequately evaluated. There is very low-quality evidence that introducing regulations as such may or may not result in a decrease in fatal and non-fatal injuries. There is also very low-quality evidence that regionally oriented safety campaigns, training, inspections or the introduction of occupational health services may not reduce non-fatal injuries in construction companies. There is very low-quality evidence that company-oriented safety interventions such as a multifaceted safety campaign, a multifaceted drug workplace programme and subsidies for replacement of scaffoldings may reduce non-fatal injuries among construction workers. More studies, preferably cluster-randomised controlled trials, are needed to evaluate different strategies to increase the employers' and workers' adherence to the safety measures prescribed by regulation.

Incidence of sharps injuries in surgical units, a meta-analysis and meta-regression.

BACKGROUND: Sharps injuries occur often among surgical staff, but they vary considerably. METHODS: We searched PubMed and Embase for studies assessing the incidence of sharps injuries. We combined the incidence rates of similar studies in a random effects meta-analysis and explored heterogeneity with meta-regression. RESULTS: We located 45 studies of which 11 were randomized control trials, 15 were follow-up studies, and 19 were cross-sectional studies. We categorized injuries as self-reported, glove perforations, or administrative injuries. We calculated the population at risk as person-years and as person-operations (po). Meta-analysis of the incidence rate based on the best outcome measure resulted in 13.2 injuries per 100 time-units (95% confidence interval [CI], 4.7-37.1; I2 = 100%). Per 100 person-years, the injury rate was 88.2 (95% CI, 61.3-126.9; 21 studies) for self-reported injuries, 40.0 for perforations (95% CI, 19.2-83.5; 15 studies), and 5.8 for administrative injuries (95% CI, 2.7-12.2; 5 studies). Per 100 po, the respective figures were 2.1 (95% CI, 0.8-5.0; 4 studies), 11.1 (95% CI, 6.6-18.9, 15 studies), and 0.1 (95% CI, 0.05-0.21). I2 values were all above 90%. Meta-regression indicated lower incidence rates in studies that used perforations per po. CONCLUSIONS: A surgeon will have a sharps injury in about 1 in 10 operations . Reporting of sharps injuries in surgical staff should be standardized per 100 po and be assessed in prospective follow-up studies.