Increased nuchal translucency, normal karyotype and infant development.

OBJECTIVE: To investigate whether chromosomally normal fetuses with a nuchal translucency (NT) ≥ 99th percentile(3.5 mm) in the first trimester have an increased risk of delayed development at 2 years of age. METHODS: The study included children of women from 10 Danish hospitals who had fetal NT either ≥ 99th percentile (Group 1) or <95th percentile (Group 2) in the first trimester. The groups were matched by gender,gestational age at birth and maternal age. There were twice as many children in Group 2 as in Group 1. Follow-up was conducted at 2 years of age, infant development being assessed by the 'Ages and Stages Questionnaire'. The cutoff value for delayed development was defined as the 5th percentile from the first 100 questionnaires from Group 2. RESULTS: In a 1-year period 202 of 33 266 fetuses (0.6%)had NT ≥ 3.5 mm. Of these, 99 (49.0%) were liveborn with normal karyotype and normal ultrasound findings during pregnancy. The response rate to the ASQ was 83.3% in Group 1 and 71.4% in Group 2. A low ASQ score was found in 1.3% (1/80) and 4.4% (6/137)in Groups 1 and 2, respectively (P = 0.265), but no difference was found in the mean ASQ score between the two groups (P = 0.160). CONCLUSION: Fetuses with NT ≥ 99th percentile, normal karyotype and normal ultrasound findings during pregnancy had no increased risk of developmental delay at 2 years of age compared with fetuses with normal NT(<95th percentile).

Fetal growth and congenital malformations.

OBJECTIVES: To ascertain whether the risk for congenital malformations is increased in pregnancies with deviating fetal growth, i.e. in those in which the estimated date of delivery (EDD) was postponed more than 1 week at the second-trimester ultrasound fetometry scan, or those suspected of intrauterine growth restriction at routine ultrasound fetometry in the third trimester. METHODS: The study period was 1994-2003. We used the Swedish Medical Birth Register to identify pregnancies with appropriate data (n = 605 845). A regional ultrasound database consisting of 73 092 pregnancies was used for more detailed data and analysis of the third-trimester fetal growth. The number of congenital malformations was ascertained from three national health registers. RESULTS: We found a moderately increased risk for any malformation in the group of fetuses in which the EDD was postponed > 1 week. The strongest effect was seen for chromosome anomalies and central nervous system malformations, including neural tube defects. In the third trimester, an increased risk for fetal malformations was found in asymmetrically vs. symmetrically growth-restricted fetuses, perhaps more strongly when adjustment of the EDD had been done at the dating scan. CONCLUSIONS: Fetuses in which the EDD differs between that calculated by the last menstrual period and that calculated by second-trimester ultrasound measurement seem to have an increased risk for congenital malformations, including chromosomal anomalies. A targeted ultrasound examination for malformation screening might be recommended for this group. A similar policy might be recommended when intrauterine growth restriction, especially of the asymmetrical type, is suspected later in pregnancy.

Bioaccumulation of PCBs in burbot (Lota lota L.) after delivery in natural food.

Burbot (Lota lota) caught from Lake Päijänne, Central Finland, were exposed under laboratory conditions to four polychlorinated biphenyl (PCB) congeners delivered through diet, and accumulation of congeners to muscle, intestine, gonads, and liver were determined. The selected PCB congeners (PCB18, PCB44, PCB137, and PCB169) were added to intact dead vendace (Coregonus albula) and burbot were fed 5 or 10 contaminated meals (2- and 4-week experiment, respectively). Concentrations of fed congeners were different in the examined tissues. The highest concentrations of all the congeners were found in the livers of burbot. The mean retention efficiencies were 65.0% and 81.7% after 5 and 10 oral doses, respectively. The retention efficiency of the coplanar 169 was lower than those of the other fed congeners. The background organochlorine concentrations of the burbot of this study were compared with the PCB concentrations of burbot caught in the 1970s from Lake Päijänne. These concentrations were compared in order to clarify the PCB load and persistence in a boreal aquatic food web. The total PCB concentration in burbot has not declined during the last decades. The most abundant PCB congeners in the field were PCB138 and PCB153. Residual concentrations of pesticides were also found, especially the DDE, which is a metabolite of DDT.

How to identify twins at low risk of spontaneous preterm delivery.

OBJECTIVE: The aim of this study was to evaluate transvaginal sonographic assessment of cervical length at 23 weeks as a screening test for spontaneous preterm delivery in order to define a cut-off value that could be used to select twin pregnancies at low risk of spontaneous preterm delivery. METHODS: In a prospective multicenter study of 383 twin pregnancies included before 14 + 6 weeks a cervical scan with measurement of the cervical length was performed at 23 weeks' gestation. The results were blinded for the clinicians if the cervical length was > or = 15 mm. The rates of spontaneous delivery at different cut-off levels of cervical length were determined. RESULTS: Eighty-nine percent of the twins had dichorionic placentation and 58% were conceived after assisted reproduction. The rate of spontaneous preterm delivery was 2.3% (1.5% for dichorionic (DC) and 9.1% for (MC) monochorionic twins) before 28 weeks and 18.5% (17.1% for DC and 29.5% for MC twins) before 35 weeks. The screen-positive rate was 5% for a cervical length < or = 20, 7-8% at < or = 25, 16-17% at < or = 30 and 34-48% at < or = 35 mm depending on chorionicity. The false-negative rate (1 - negative predictive value) ranged from 1.2% at 28 weeks to 18.6% at 35 weeks for all twins. Receiver-operating characteristics curves showed that the sensitivity increased with declining gestational age with cut-off levels of highest accuracy at 21 mm for 28 weeks and 29 mm for 33 weeks. CONCLUSIONS: Cervical length measurement at 23 weeks of gestation is a good screening test for predicting twins at low risk of preterm and very preterm delivery, especially in DC twins. The present results suggest that a cut-off of 25 mm should be recommended.

Early amniocentesis and congenital foot deformities.

OBJECTIVE: Several studies have shown an increased risk of congenital foot derformities after early amniocentesis. These studies have comprised amniocenteses performed before 13 completed gestational weeks. In this study, the risk of foot deformities after amniocentesis performed at 12-14 completed gestational weeks was determined. METHODS: 3,469 genetic amniocenteses in singleton pregnancies performed before 15 completed gestational weeks were studied. The intention was to perform the amniocenteses at 12-14 weeks of gestation, but 32 amniocenteses were performed at the gestational age 11 weeks + 5 days or 11 weeks + 6 days. The pregnancies were followed up with regard to fetal loss and leakage of amniotic fluid. After birth, newborns with a diagnosis of foot deformity were identified from the Swedish Medical Birth Registry. The observed number of foot deformities was then compared with the expected number which was calculated stratified for delivery hospital, year of birth, and maternal age. RESULTS: The observed number of foot deformities was significantly higher than the expected: exact odds ratio 1.74 (exact 95% confidence interval 1.06-2.69). The rate of spontaneous abortions after the procedure was 1.8%, and the rate of leakage of amniotic fluid was 1.9%. There was a significant trend for all complications to decrease with increasing gestational age at amniocentesis. CONCLUSION: Women undergoing amniocentesis at 11+5 to 14+6 gestational weeks have an increased risk of giving birth to a child with a congenital foot deformity.

Effects of dissolved organic material on binding and toxicokinetics of pyrene in the waterflea Daphnia magna.

The binding and bioavailability of pyrene was studied in the laboratory in two humic fresh waters and in a reference water without dissolved organic material (DOM), measured as dissolved organic carbon (DOC). The uptake of pyrene by Daphnia magna in short-term (24 h) accumulation experiments was fitted to a first-order rate-kinetic equation to calculate simultaneous uptake and elimination rates. The partition coefficients of pyrene to DOC (KDOC) were 37.1 x 103 in Pielisjoki River (9.4 mg DOC L(-1)), and 34.9 x 103 in Lake Kontiolampi (17.4 mg DOC L(-1)) waters, indicating similar binding affinities of pyrene for both humic waters. The uptake clearance of pyrene (ku) in the DOC-rich Lake Kontiolampi water was 290.4 ml g wet weight(-1) h(-1), which was lower than those in Pielisjoki River and DOC-free waters (395.8 and 346.0 ml g wet weight(-1) h(-1), respectively). Pyrene elimination (ke) was in average 0.2 h(-1) with no significant differences between the waters. The observed bioconcentration factors of pyrene in Pielisjoki River and Lake Kontiolampi waters were 84% and 46% of that in the DOC-free reference water, respectively, thus indicating that a high concentration of DOC is needed to decrease the bioavailability of waterborne pyrene to D. magna.

Atrazine uptake, elimination, and bioconcentration by periphyton communities and Daphnia magna: effects of dissolved organic carbon.

The bioconcentration and toxicokinetics of atrazine in three different periphyton communities and in laboratory reared Daphnia magna were studied in natural and artificial waters with different dissolved organic carbon (DOC) concentrations and qualities. The exposure concentrations were similar to those short-lived peak concentrations found in contaminated waters. Atrazine uptake and elimination were very fast, and the bioconcentration was low both in periphyton and D. magna. The bioconcentration factors in D. magna were approx. 16% of those in periphyton. The uptake and elimination rates were also higher in periphyton than in Daphnia. The periphyton properties affected the bioconcentration of atrazine more than the DOC concentration and water quality. A steady state was reached within a few hours of uptake by the periphyton and within 24 h by D. magna. A residue of atrazine was left in the periphyton and D. magna after an 8-h biphasic depuration with clearly distinct fast and slow phases. In D. magna, atrazine may be eliminated during the normal life span of the organism. These results suggest that DOC has a minor influence on the toxicokinetics of atrazine.

UV-B-Induced acute toxicity of pyrene to the waterflea Daphnia magna in natural freshwaters.

The effects of various water characteristics in natural freshwaters on the acute toxicity of one polycyclic aromatic hydrocarbon (PAH), pyrene, to a pelagic invertebrate Daphnia magna was studied under ultraviolet B (UV-B) radiation and in the dark. Pyrene was photoactivated and was more toxic to D. magna in the presence of UV-B radiation. Dissolved organic material (DOM), measured as dissolved organic carbon (DOC), significantly reduced the photoenhanced toxicity of pyrene. Under UV-B radiation the EC(50) values were lower and in relation to the amount of DOM, ranging from 3.0 to 30.0 microg/L pyrene, whereas in the dark they were between 29.2 and 54.8 microg/L and not related to the amount of DOM in the waters. Although the condition and mortality of the daphnids in the control groups were not affected by UV-B irradiation, the increased toxicity was considered to be either an additive or a synergistic effect of both the photomodified pyrene and the stressing light conditions of UV-B. The measured binding of pyrene to DOM was low, although it was related to the amount of DOC. Despite the relatively high intensity of UV-B used, humic substances in the waters remained undegraded. It was thus concluded that with their brownish-yellowish color, waters rich in humic substances decreased the photomodification of the freely dissolved parent compound simply by diminishing the light penetration in these waters and, by implication, contact with the intact compound. These results suggest that DOM in surface waters plays an important role in protecting against the photoinduced toxicity of PAHs.

Metabolic and hormonal effects of exercise in mild streptozotocin diabetes.

Metabolic and hormonal changes produced by muscular exercise were studied in rats with mild streptozotocin diabetes. In both diabetic and control animals the mean blood glucose increased and liver glycogen decreased during exercise. The postexercise blood glucose level correlated with the liver glycogen content in diabetic rats. A decrease of blood glucose occurred in some diabetic animals, and these also showed a decrease of liver glycogen to very low levels during exercise. During exercise the rise of plasma glycerol was higher in diabetic than in control animals, but changes in circulating free fatty acids, acetone bodies, insulin, corticosterone, lactate, and acid-base equilibrium were similar in the two groups. The results indicate that the only abnormal metabolic response to exercise in rats with mild diabetes is a slight increase of lipid mobilization.