OBJECTIVE:To examine the maternal and foetal risks of adverse pregnancy outcome in relation to maternal obesity, expressed as body mass index (BMI, kg=m 2 ) in a large unselected geographical population. DESIGN: Retrospective analysis of data from a validated maternity database system which includes all but one of the maternity units in the North West Thames Region. A comparison of pregnancy outcomes was made on the basis of maternal BMI at booking. SUBJECTS: A total of 287 213 completed singleton pregnancies were studied including 176 923 (61.6%) normal weight (BMI 20 -24.9), 79 014 (27.5%) moderately obese ) and 31 276 (10.9%) very obese (BMI ! 30) women. MEASUREMENTS: Ante-natal complications, intervention in labour, maternal morbidity and neonatal outcome were examined and data presented as raw frequencies and adjusted odds ratios with 99% confidence intervals following logistic regression analysis to account for confounding variables. RESULTS: Compared to women with normal BMI, the following outcomes were significantly more common in obese pregnant women (odds ratio (99% confidence interval) for BMI 25 -30 and BMI ! 30 respectively): gestational diabetes mellitus (1.68 (1.53 -1.84), 3.6 (3.25 -3.98)); proteinuric pre-eclampsia (1.44 (1.28 -1.62), 2.14 (1.85 -2.47)); induction of labour (2.14 (1.85 -2.47), 1.70 (1.64 -1.76)); delivery by emergency caesarian section (1.30 (1.25 -1.34), 1.83 (1.74 -1.93)); postpartum haemorrhage (1.16 (1.12 -1.21), 1.39 (1.32 -1.46)); genital tract infection (1.24 (1.09 -1.41), 1.30 (1.07 -1.56)); urinary tract infection (1.17 (1.04 -1.33), 1.39 (1.18 -1.63)); wound infection (1.27 (1.09 -1.48), 2.24 (1.91 -2.64)); birthweight above the 90th centile (1.57 (1.50 -1.64), 2.36 (2.23 -2.50)), and intrauterine death (1.10 (0.94 -1.28), 1.40 (1.14 -1.71)). However, delivery before 32 weeks' gestation (0.73 (0.65 -0.82), 0.81 (0.69 -0.95)) and breastfeeding at discharge (0.86 (0.84 -0.88), 0.58 (0.56 -0.60)) were significantly less likely in the overweight groups. In all cases, increasing maternal BMI was associated with increased magnitude of risk. CONCLUSION: Maternal obesity carries significant risks for the mother and foetus. The risk increases with the degree of obesity and persists after accounting for other confounding demographic factors. The basis of many of the complications is likely to be related to the altered metabolic state associated with morbid obesity.

The obstetric risks of adverse outcome during pregnancy in women aged > or =35 years were quantified using a retrospective analysis of data from 385 120 singleton pregnancies in the North West Thames Region, UK, between 1988 and 1997. A comparison of pregnancy outcome was made on the basis of maternal age at delivery: 18-34 years (n = 336 462), 35-40 years (n = 41 327) and women aged > 40 years (n = 7331). Women aged <18 years (n = 5246) were excluded from the study. Data are presented as percentages of 18-34 year old women, 35-40 year old and > 40 year old women, with adjusted odds ratios (OR) according to age group. Pregnant women aged 35-40 years were at increased risk of: gestational diabetes, OR = 2.63 [99% confidence interval (CI) 2.40-2.89]; placenta praevia = 1.93 (1.58-2.35); breech presentation = 1.37 (1.28-1.47); operative vaginal delivery = 1.5 (1.43-1.57); elective Caesarean section = 1.77 (1.68-1.87); emergency Caesarean section = 1.59 (1.52-1.67); postpartum haemorrhage = 1.14 (1.09-1.19); delivery before 32 weeks gestation = 1.41 (1.24-1.61); birthweight below the 5th centile = 1.28 (1.20-1. 36); and stillbirth = 1.41 (1.17-1.70). Women aged >40 years had higher OR for the same risks. Pregnant women aged >/=35 years are at increased risk of complications in pregnancy compared with younger women.

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Background: Our aim was to identify and compare modifiable risk factors associated with adverse pregnancy outcomes in women with type 1 and type 2 diabetes and to identify effective maternity clinics. Methods:We included 17,375 pregnancies in 15,290 women with diabetes in a populationbased cohort study across 172 maternity clinics in England, Wales and the Isle of Man.Obstetric complications (preterm delivery, large birthweight) and adverse pregnancy outcomes (congenital anomaly, stillbirth, neonatal death) were obtained for pregnancies completed between 01 January 2014 and 31 December 2018. We assessed associations between modifiable (glycaemia, obesity, clinic) and non-modifiable risk factors (age, deprivation, ethnicity) with pregnancy outcomes.Results: Of 17,375 pregnancies, 8,690 (50.0%) were in women with type 1 and 8,685 (50.0%) in women with type 2 diabetes. The rates of preterm delivery (42.5% type 1, 23.4% type 2), and large birthweight (52.2% type 1, 26.2% type 2) were higher in type 1 diabetes (p<0.001).The prevalence of congenital anomaly (44.8/1000 type 1, 40.5/1000 type 2; p=0.175), and stillbirth (10.4/1000 type 1, 13.5/1000 type 2; p=0.072) did not differ but neonatal death rates (7.4/1000 type 1, 11.2/1000 type 2; p=0.013) were higher in type 2 diabetes. Independent risk factors for perinatal death were third trimester HbA1c > 48mmol/mol (OR 3.06, 95% CI 2.16 to 4.33), living in the highest deprivation quintile (OR 2.29 95% CI 1.16 to 4.52) and having type 2 diabetes (OR 1.65 95% CI 1.18 to 2.31). Variations in glycaemia and large birthweight were associated with maternal characteristics (diabetes duration, deprivation, BMI) without substantial differences between clinics.Interpretation: Our data highlight persistent adverse pregnancy outcomes in type 1 and type 2 diabetes. Maternal glycaemia and obesity are the key modifiable risk factors. No clinics were achieving appreciably better outcomes, suggesting that healthcare system changes are needed

Pregnant women less than 18 years old were more likely to deliver preterm than older women. In most other respects they have less maternal and perinatal morbidity and were more likely to have normal vaginal deliveries.

Objective To determine the maternal and fetal risk of adverse outcome during pregnancy in relation to low maternal body mass index in an unselected population. Design Retrospective analysis.Methods Information for the years between 1988 and 1997 was extracted from a validated maternity database, including all but one of the maternity units in the North West Thames Region; 215,105 completed singleton pregnancies were studied. Comparison of pregnancy outcome was made on the basis of maternal body mass index at booking. There were 176,923 with a normal weight body mass index ( 20 , 25). There were 38,182 with an underweight body mass index (, 20). Comparisons included antenatal complications (e.g. gestational diabetes, pre-eclampsia); intervention in labour, maternal morbidities (e.g. infection, postpartum haemorrhage, pulmonary thromboembolism); and neonatal outcome (admitted to special care baby unit at 24 hour of age, gestation at delivery, birthweight, stillbirth). Data are presented as percentages of outcomes in the normal and underweight groups with adjusted odds ratios and con®dence intervals according to body mass index group. Results In the underweight group only antenatal anaemia, preterm delivery and birthweight below the 5th centile were more frequent than in women of normal body mass index. The prevalence of certain complications, including development of gestational diabetes mellitus, pre-eclampsia, obstetric intervention and postpartum haemorrhage, were signi®cantly lower in those with low body mass index.Conclusion Low maternal body mass index is associated with increased prevalence of some pregnancy complications, notably preterm delivery and low birthweight, but overall the outcome is favourable and several adverse outcomes are less common in this group of women.

Segmented polyurethane multiblock polymers containing polydimethylsiloxane and polyether soft segments form tough and easily processed thermoplastic elastomers. Two commercially available examples, Elast-Eon E2A (denoted as E2A) and PurSil 35 (denoted as P35), were evaluated for molecular and mechanical stability after immersion in buffered water for up to 52 weeks at temperatures ranging from 37 to 85 °C. Dynamic mechanical spectroscopy experiments, performed in tension and shear, were used to characterize the linear viscoelastic properties of compression-molded (dry) specimens. Small-angle X-ray scattering measurements indicated a disorganized microphase-separated morphology for all test conditions. Upon aging in phosphate buffered saline, samples of E2A and P35 were analyzed by size exclusion chromatography (SEC) and tensile testing as a function of time and temperature. The absolute molar mass of each material prior to aging in water was determined by SEC using a multiangle light scattering detector. Aging at 85 °C and 52 weeks lead to a 67% and 50% reduction in molar mass from the original values for E2A and P35, respectively. We attribute the reduction in molar mass to hydrolysis of the polymer backbone and have evaluated the data using a pseudo-zero-order kinetics analysis. The temperature dependence of the extracted rate data is consistent with an activated (i.e., Arrhenius) process, and thus all the molar mass reduction data can be reduced to a single master curve. Concomitant with the reduction in molar mass, E2A and P35 transformed with aging from strain-hardening to strain-softening materials, characterized by substantially reduced tensile strength (stress at failure) and ultimate elongation (strain at failure) relative to the original properties.

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