To investigate whether advanced maternal age is associated with preterm birth, irrespective of parity.
Population-based registry study.
Swedish Medical Birth Register.
First, second, and third live singleton births to women aged 20 years or older in Sweden, from 1990 to 2011 (n = 2 009 068).
Logistic regression analysis was used in each parity group to estimate risks of very and moderately preterm births to women at 20-24, 25-29, 30-34, 35-39, and 40 years or older, using 25-29 years as the reference group. Odds ratios (ORs) were adjusted for year of birth, education, country of birth, smoking, body mass index, and history of preterm birth. Age-related risks of spontaneous and medically indicated preterm births were also investigated.
Very preterm (22-31 weeks of gestation) and moderately preterm (32-36 weeks) births.
Risks of very preterm birth increased with maternal age, irrespective of parity: adjusted ORs in first, second, and third births ranged from 1.18 to 1.28 at 30-34 years, from 1.59 to 1.70 at 35-39 years, and from 1.97 to 2.40 at =40 years. In moderately preterm births, age-related associations were weaker, but were statistically significant from 35-39 years in all parity groups. Advanced maternal age increased the risks of both spontaneous and medically indicated preterm births.
Advanced maternal age is associated with an increased risk of preterm birth, irrespective of parity, especially very preterm birth. Women aged 35 years and older, expecting their first, second, or third births, should be regarded as a risk group for very preterm birth.
Women aged 35 years and older should be regarded as a risk group for very preterm birth, irrespective of parity.
Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver disease in the world, but little is known about its potential association with pregnancy outcomes. We aimed to investigate pregnancy outcomes in NAFLD.
The Swedish Medical Birth Register (MBR) was used to identify births between 1992 and 2011 (N = 1 960 416). By linkage with the National Patient Register, we identified women with a diagnosis of NAFLD. The MBR was then used to identify outcomes: gestational diabetes, pre-eclampsia, Caesarean section, Apgar score
Department of Women's and Children's Health, Division of Reproductive and Perinatal Health Care, and the Department of Clinical Science and Education, Södersjukhuset (KI SÖS), Karolinska Institutet, Stockholm, and the Centre for Clinical Research, Dalarna, Falun, Sweden; and the Center for Evidence Based Practice, Faculty of Health Sciences, Bergen University College, and the Department of Clinical Science, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway.
To investigate the association between advanced maternal age and adverse pregnancy outcomes and to compare the risks related to advanced maternal age with those related to smoking and being overweight or obese.
A population-based register study including all nulliparous women aged 25 years and older with singleton pregnancies at 22 weeks of gestation or greater who gave birth in Sweden and Norway from 1990 to 2010; 955,804 women were analyzed. In each national sample, adjusted odds ratios (ORs) of very preterm birth, moderately preterm birth, small for gestational age, low Apgar score, fetal death, and neonatal death in women aged 30-34 years (n=319,057), 35-39 years (n=94,789), and 40 years or older (n=15,413) were compared with those of women aged 25-29 years (n=526,545). In the Swedish sample, the number of additional cases of each outcome associated with maternal age 30 years or older, smoking, and overweight or obesity, respectively, was estimated in relation to a low-risk group of nonsmokers of normal weight and aged 25-29 years.
The adjusted OR of all outcomes increased by maternal age in a similar way in Sweden and Norway; and the risk of fetal death was increased even in the 30- to 34-year-old age group (Sweden n=826, adjusted OR 1.24, 95% confidence interval [CI] 1.13-1.37; Norway n=472, adjusted OR 1.26, 95% CI 1.12-1.41). Maternal age 30 years or older was associated with the same number of additional cases of fetal deaths (n=251) as overweight or obesity (n=251).
For the individual woman, the absolute risk for each of the outcomes was small, but for society, it may be significant as a result of the large number of women who give birth after the age of 30 years.
To assess the risk factors for preterm birth in twin pregnancies, particularly monochorionicity.
A cohort study of 767 sets of twins, each twin weighing more than 500 g, born between January 1, 1992, and December 31, 2001, at St. Joseph's Health Care in London, Ontario. Statistical analysis was performed using forward stepwise logistic regression models, with gestational age at birth less than 28 or 32 weeks as the outcome.
Polyhydramnios and chorioamnionitis were significant risk factors for preterm birth prior to 28 or 32 weeks' gestation. Monochorionicity was a risk factor for preterm birth prior to 32 weeks' gestation. Past term birth and maternal age over 30 years were associated with reduced risk for preterm birth.
Monochorionic placentation is a significant risk factor for preterm twin birth.
Is the perinatal health of first-born children affected by the mother's previous induced abortion(s) (IAs)?
Prior IAs, particularly repeat IAs, are correlated with an increased risk of some health problems at first birth; even in a country with good health care quality.
A positive association between IA and risk of preterm birth or a dose-response effect has been found in some previous studies. Limited information and conflicting results on other infant outcomes are available.
Nationwide register-based study including 300 858 first-time mothers during 1996-2008 in Finland.
All the first-time mothers with a singleton birth (obtained from the Medical Birth Register) in the period 1996-2008 (n = 300 858) were linked to the Abortion Register for the period 1983-2008.
Of the first-time mothers, 10.3% (n = 31 083) had one, 1.5% had two and 0.3% had three or more IAs. Most IAs were surgical (88%) performed before 12 weeks (91%) and carried out for social reasons (97%). After adjustment, perinatal deaths and very preterm birth (
To assess the existing evidence of associations between assisted conception and cerebral palsy (CP), autism spectrum disorders (ASD), and developmental delay.
Forty-one studies identified in a systematical PubMed and Excerpta Medica Database (EMBASE) search for articles published from January 1, 1996, to April 1, 2008.
Studies written in English comparing children born after assisted conception with children born after natural conception assessing CP, ASD, and developmental delay, based on original data with a follow-up of 1 year or more. Main Exposures In vitro fertilization (IVF) with or without intracytoplasmic sperm injection or ovulation induction with or without subsequent intrauterine insemination.
Cerebral palsy, ASD, and developmental delay.
Nine CP studies showed that children born after IVF had an increased risk of CP associated with preterm delivery. In our meta-analysis including 19 462 children exposed to IVF, we estimated a crude odds ratio of 2.18 (95% confidence interval, 1.71-2.77). Eight ASD studies and 30 studies on developmental delay showed inconsistent results. No studies assessed the risk of CP, ASD, or developmental delay in children born after ovulation induction exclusively.
Methodological problems were revealed in the identified studies, and the gaps in our knowledge about the long-term outcomes of children born after assisted conception are considerable, including a lack of information on the long-term consequences of ovulation induction. Possible associations with ASD and developmental delay need assessment in larger studies. Studies on assisted conception and CP from countries outside of Scandinavia are needed, including detailed information on time to pregnancy, underlying cause of infertility, and type of IVF treatment.
OBJECTIVE: The risk of adverse foetal outcomes was investigated in offspring to men with coeliac disease (CD) diagnosed prior to infant birth and in offspring to men who did not receive a diagnosis of CD until after the delivery. MATERIAL AND METHODS: A cohort study was based on national registry data restricted to women aged 15-44 years with singleton live-born infants, with linkage between the Swedish national birth registry (1973-2001) and the national inpatient registry (1964-2001). A total of 1059 offspring to men who had received a diagnosis of CD were included: 554 offspring to men diagnosed prior to birth and 505 offspring to men diagnosed after infant birth. RESULTS: Undiagnosed CD in the father was associated with an increased risk of caesarean section (adjusted odds ratio (AOR)=1.83; 95% confidence interval (CI) for AOR=1.13-2.95; p=0.014) but was otherwise not linked to adverse pregnancy outcome: (intrauterine growth retardation (OR=1.37; 95% CI=0.91-2.07), low birth-weight (OR=1.41; 95% CI=0.93-2.12), very low birth-weight (OR=1.21; 95% CI=0.39-3.77), preterm birth (OR=1.10; 95% CI=0.74-1.62), and very preterm (OR=0.62; 95% CI=0.09-4.40)). A paternal diagnosis of CD made before infant birth was not associated with adverse foetal outcome. CONCLUSIONS: CD in the father is not a risk factor for unfavourable foetal outcome. The increased risk for caesarean section in offspring to men with undiagnosed CD in this study may be due to multiple comparisons.
Nathalie Auger is with the Institut national de santé publique du Québec, Montreal, Canada; the Research Centre of the University of Montreal Hospital Centre, Montreal; and the Department of Social and Preventive Medicine, University of Montreal. Anne V. Hansen and Laust Mortensen are with the Section of Social Medicine, University of Copenhagen, Copenhagen, Denmark.
We sought evidence to support the hypothesis that advancing maternal age is potentially causing a rise in preterm birth (PTB) rates in high-income countries.
We assessed maternal age-specific trends in PTB using all singleton live births in Denmark (n = 1 674 308) and Quebec (n = 2 291 253) from 1981 to 2008. We decomposed the country-specific contributions of age-specific PTB rates and maternal age distribution to overall PTB rates over time.
PTB rates increased from 4.4% to 5.0% in Denmark and from 5.1% to 6.0% in Quebec. Rates increased the most in women aged 20 to 29 years, whereas rates decreased or remained stable in women aged 35 years and older. The overall increase over time was driven by age-specific PTB rates, although the contribution of younger women was countered by fewer births at this age in both Denmark and Quebec.
PTB rates increased among women aged 20 to 29 years, but their contribution to the overall PTB rates was offset by older maternal age over time. Women aged 20 to 29 years should be targeted to reduce PTB rates, as potential for prevention may be greater in this age group.
To investigate the association between cone depth of the loop electrosurgical excision procedure (LEEP) of the cervix and subsequent risk of spontaneous preterm delivery.
The study included all deliveries in Denmark over a 9-year period, 1997-2005, with information obtained from various public health registries. Of the 552,678 singleton deliveries included in the study, 19,049 were preterm and 8,180 were subsequent to LEEP. Of the 8,180 deliveries with prior LEEP, 273 were subsequent to two or more LEEPs. Of the deliveries subsequent to only one LEEP, we extracted information about cone depth on 3,605 deliveries, of which 223 were preterm (6.2%). Logistic regression analyses were used to evaluate association between cone characteristics and the subsequent risk of preterm delivery, with simultaneous adjustment for potential confounders.
Increasing cone depth was associated with a significant increase in the risk of preterm delivery, with an estimated 6% increase in risk per each additional millimeter of tissue excised (odds ratio 1.06, 95% confidence interval 1.03-1.09). Severity of the cone histology and time since LEEP were not associated with the risk of preterm delivery. Having had two or more LEEPs increased the risk almost fourfold for subsequent preterm delivery when compared with no LEEP before delivery, and almost doubled the risk when compared with one LEEP before delivery.
Increasing cone depth of LEEP is directly associated with an increasing risk of preterm delivery, even after adjustment for several confounding factors.
Socio-economic disparities in preterm delivery have often been attributed to socially patterned smoking habits. However, most existing studies have used methods that potentially give biased estimates of the mediating effect of smoking. We used a contemporary mediation approach to study to which extent smoking during pregnancy mediates educational disparities in preterm delivery.
We performed a comparative analysis of data from three large birth cohort studies: the Danish National Birth Cohort (DNBC), the Dutch Generation R Study, and the Norwegian Mother and Child Cohort Study (MoBa). Risk of preterm delivery by maternal education is reported as risk differences and decomposed into a part explained by smoking and a part explained by other pathways.
Proportions of preterm singleton deliveries were 4.8%-4.9% in all three cohorts. Total effects of maternal education were 2.0 (95% confidence interval [CI] 1.4, 2.5), 3.2 (95% CI 0.8, 5.2) and 2.0 (95% CI 0.9, 3.0) excess preterm deliveries per 100 singleton deliveries in DNBC, Generation R and MoBa when comparing primary/lower secondary education to an academic degree or equivalent. Smoking mediated, respectively, 22%, 10% and 19% of the excess risk in the DNBC, Generation R and MoBa cohorts. Adjustment for potential misclassification of smoking only increased mediated proportions slightly.
Smoking during pregnancy explains part of educational disparities in preterm delivery, but the mediated proportion depends on the educational gradient in smoking, emphasising that educational disparities in preterm birth may be mediated by different risk factors in different countries.