A statewide database of vital records and hospital discharge summaries of obstetric and neonatal admissions for Washington State in 1987-95 was linked to the birth certificates of mothers born in the state. A total of 46,000 births to mothers of four racial/ethnic groups were studied: Whites, African-Americans, Native Americans and Hispanics. For all four groups inverse associations were found between maternal birthweight and infant low birthweight and preterm birth. The birthweight distribution of African-American mothers was displaced markedly downwards compared with the Whites; this difference in maternal birthweight is offered as a partial explanation of the greater prevalence of suboptimal pregnancy outcomes in the former. In contrast, the maternal birthweight distributions of Whites, Native Americans and Hispanics are similar; differences in pregnancy outcomes are probably more related to maternal preconceptional and postnatal factors in these groups as well as differences in pregnancy-related factors. Mothers' birthweight may have clinical value in identifying high-risk pregnancies.

Intrauterine growth retardation and low birthweight have been associated with an increased risk of insulin resistance and type II diabetes later in life. We hypothesised that maternal low birthweight is associated with an increased risk of gestational diabetes mellitus (GDM). Study subjects comprised women giving birth in Washington State between 1987 and 1995. Information for 21,528 births to non-Hispanic white women, 6359 to African-American women, 7456 to Native American women and 6496 to Hispanic women was available for analysis. All information was derived from statewide computerised vital records and hospital discharge summaries of obstetric and neonatal admissions with linkage to birth certificates of mothers. Maternal birthweight was collected from subjects' birth certificates. Information from both the birth certificates and the obstetric and neonatal admissions database was used to determine whether subjects developed GDM. Poisson regression models were estimated to calculate unadjusted and adjusted risk ratios (RRs) and 95% confidence intervals (CIs) for GDM by categories of maternal birthweight. The cumulative incidence of GDM among non-Hispanic white, African-American, Native American and Hispanic women was 2.8, 2.6, 2.7 and 3.0% respectively. After adjusting for maternal age, parity, cigarette smoking, history of chronic hypertension and participation in the Medicaid programme, non-Hispanic white women with a birthweight < 2000 g were 1.7 times more likely to have had their pregnancy complicated by GDM (RR = 1.7; 95% CI 0.8, 3.3) than those with a birthweight 3000-3999 g. The corresponding adjusted RRs for African-American, Native American, and Hispanic women were 2.8 [95% CI 1.2, 6.1], 3.1 [95% CI 1.2, 8.2] and 2.4 [95% CI 0.9, 6.0] respectively. Among African-American women, those with a birthweight > or = 4000 g also experienced a twofold increased risk of GDM (RR = 2.1; 95% CI 1.0, 4.1). This association of high birthweight and increased GDM risk was not found among women in the other three racial/ethnic groups. These findings suggest that individuals with low birthweight constitute a group at increased risk for GDM.

SUMMARYHeat stress during pregnancy in sheep is associated with respiratory alkalosis in both the mother and fetus, and, if prolonged, fetal growth is retarded. In seven pregnant sheep at 130-137 days gestation we used 15 ,um diameter radioactive microspheres to determine the effect of raising the environmental temperature from 20 to 43°C for 8 h on uteroplacental blood flows and the distribution of cardiac output in the ewe and fetus. Fetal cardiac output increased slightly from 47.0 + 3.2 (mean + S.E.M.) to 54.0 + 3-6 ml min-' (100 g tissue)-', fetal arterial pressure and heart rate were unchanged, and total vascular conductance in the fetus increased significantly from 12397 + 1111 to 14732 + 1569 ml min-kg-mmHg-' (P <0.01). Tissue blood flows (in ml min-' (100 g)-1) increased significantly (P < 0.05) in the fetal body (e.g. nasal mucosa, torso and foreleg skin, adrenal, thyroid and thymus glands, brown and omental fats, heart, urinary bladder and carcass) and the fetal brain (e.g. cerebellum, cerebral grey matter, cervical spinal cord and pituitary gland). These regional vasodilatations occurred despite a significant fall (P < 0-01) in fetal arterial 02 saturation (55.2 + 1-8 vs. 38-6 ± 2.4 %), Po2 (18.1 + 0-7 vs. 13.5 + 0.8 mmHg) and PCO2 (51.0 + 1-8 vs. 36-1 + 2-3 mmHg); under normothermic conditions hypoxia is associated with peripheral vasoconstriction. Because hypocapnia would also be expected to cause cerebral vasoconstriction it is suggested that during hyperthermia, hypoxia-and hypocapnia-induced vasoconstrictions are reduced by the release of vasodilator substances, or a decrease of sympathoadrenal effector responses. Blood flow to the fetal and maternal sides of the placenta did not change during the heat stress, suggesting that perfusion-dependent transfer of heat from fetus to mother across the placenta does not increase under hyperthermic conditions.

Girth welds were produced using a manual CTAW procedure in solid and clad stainless steel line pipe. Corrosion behavior in CO2 and NaC1 solution simulating wet gas was evaluated.Girth Welding Line Pipe Made from Stainless Steel Either Solid or Internally Clad -- Phase II. See also L51498.