An analysis of intra-uterine growth retardation in rural Malawi

OBJECTIVE: (1) To describe the sex-specific, birth weight distribution by gestational age of babies born in a malaria endemic, rural area with high maternal HIV prevalence; (2) to assess the contribution of maternal health, nutritional status and obstetric history on intra-uterine growth retardation (IUGR) and prematurity. METHODS: Information was collected on all women attending antenatal services in two hospitals in Chikwawa District, Malawi, and at delivery if at the hospital facilities. Newborns were weighed and gestational age was assessed through post-natal examination (modified Ballard). Sex-specific growth curves were calculated using the LMS method and compared with international reference curves. RESULTS: A total of 1423 live-born singleton babies were enrolled; 14.9% had a birth weight <2500 g, 17.3% were premature (<37 weeks) and 20.3% had IUGR. A fall-off in Malawian growth percentile values occurred between 34 and 37 weeks gestation. Significantly associated with increased IUGR risk were primiparity relative risk (RR) 1.9; 95% CI 1.4--2.6), short maternal stature (RR 1.6; 95% CI 1.0--2.4), anaemia (Hb<8 g/dl) at first antenatal visit (RR 1.6; 95% CI 1.2--2.2) and malaria at delivery (RR 1.4; 95% CI 1.0--1.9). Prematurity risk was associated with primiparity (RR 1.7; 95% CI 1.3--2.4), number of antenatal visits (RR 2.2; 95% CI 1.6--2.9) and arm circumference <23 cm (RR 1.9; 95% CI 1.4--2.5). HIV infection was not associated with IUGR or prematurity. CONCLUSION: The birth-weight-for-gestational-age, sex-specific growth curves should facilitate improved growth monitoring of newborns in African areas where low birth weight and IUGR are common. The prevention of IUGR requires improved malaria control, possibly until late in pregnancy, and reduction of anaemia.     

Exposure to pesticides and cryptorchidism: geographical evidence of a possible association.

Synthetic hormone-disrupting chemicals may play a role in the increased frequency of cryptorchidism observed in some studies. We used a spatial ecological design to search for variations in orchidopexy rates in the province of Granada in Spain and to search for relationships between these differences and geographical variations in exposure to pesticides. Orchidopexy rates were estimated for the period from 1980 to 1991 in all municipalities and health care districts served by the University of Granada Hospital. A random sample of males of the same age (1-16 years) admitted for any reason during the same period was used to estimate inpatient control rates. Each municipality was assigned to one of four levels of pesticide use. We used Poisson homogeneity tests to detect significant differences in rates of orchidopexy between districts and between levels of pesticide use. Poisson and logistic regression models were also used to estimate the strength of association between orchidopexy and level of pesticide use. Orchidopexy rates tended to be higher in districts near the Mediterranean coast where intensive farming is widespread. The city of Granada, where the reference hospital is located, also had higher figures both for orchidopexy and inpatient control rates. Regression models showed that the strength of association between orchidopexy and level of pesticide use tended to increase with higher levels of use, with the exception of level 0 (mainly in the city of Granada). Our results are compatible with a hypothetical association between exposure to hormone-disruptive chemicals and the induction of cryptorchidism. Several methodological limitations in the design make it necessary to evaluate the results with caution.     

Smoking during pregnancy: foetal growth retardation and other risks for the newborn

In spite of the well-known effect of tobacco on embryo growth retardation, of the higher perinatal mortality of the offspring of smoking mothers, and of the dependence of perinatal mortality risk on small birth weight, it has consistently been found that small infants of smoking mothers have lower mortality rates than small infants of non-smoking mothers. This problem was studied on the perinatal database of a hospital, using adverse outcomes (death or Apgar score <7 at the 10th minute of life) as endpoints rather than perinatal or foetal mortality. A stochastic model constructed to account for cause-effect relations demonstrated that tobacco influences weight and mortality by independent pathways. Furthermore, this model shed some light on the non-tobacco determinants of small birth weight and neonatal morbidity. The method undertaken, based on the use of latent variables, had the advantage of analysing the prevalence, consequences and interactions of some risk factors without identifying them.     

抗坏血酸对细菌脂多糖引起发育毒性保护作用

目的研究抗坏血酸（AA）对细菌脂多糖（LPS）引起宫内胎儿死亡（IUFD）、生长发育迟缓（IUGR）和骨骼发育迟缓的保护作用。方法实验1：LPS组小鼠于妊娠第15～17d经腹腔注射LPS，LPS＋AA组在LPS处理前和／或处理后经腹腔注射给予AA，对照组给予等容量的生理盐水或从。所有孕鼠于妊娠第18d处死。实验2：LPS组小鼠于妊娠第16d注射LPS，LPS＋AA组在LPS处理前和／或处理后经腹腔注射给予AA，对照组给予等容量的生理盐水或AA。LPS处理后6h处死孕鼠。结果LPS＋AA预处理组平均每窝死胎数明显低于单纯LPS处理组，LPS＋从后和预＋后处理组平均每窝死胎数与单纯LPS组比较差异无统计学意义；AA预、后和预＋后处理均显著抑制LPS引起IUGR和枕骨骨化不全。从预和后处理均显著抑制LPS引起母肝、胎肝和胎盘组织脂质过氧化。但从预处理的作用强于后处理。结论从预处理通过抑制LPS引起的氧化应激，预防LPS引起IUFD、IUGR和骨骼发育迟缓；AA后处理和预＋后处理对抗LPS引起IUGR和骨骼发育迟缓，但对LPS引起的IUFD无明显保护作用。     

The association of waterborne chloroform with intrauterine growth retardation.

The potential reproductive effects of long-term, low-dose exposure to chloroform have received little attention despite the known, acute toxicity of high exposures and the wide-spread occurrence of low concentrations in drinking water. We studied the association of waterborne chloroform with low birthweight (less than 2,500 gm), prematurity (less than 37 weeks gestation), and intrauterine growth retardation (less than 5th percentile of weight for gestational age). Cases were not mutually exclusive, but each outcome was analyzed independently. Birth certificates from January 1, 1989, to June 30, 1990, were used to identify cases and randomly selected controls. All were live, singleton infants born to non-Hispanic, white women from Iowa towns with 1,000-5,000 inhabitants. Exposures to chloroform and other trihalomethanes were ecologic variables based on maternal residence and a 1987 municipal water survey. After adjustment for maternal age, parity, adequacy of prenatal care, marital status, education, and maternal smoking by multiple logistic regression, residence in municipalities where chloroform concentrations were greater than or equal to 10 micrograms/liter was associated with an increased risk for intrauterine growth retardation (odds ratio = 1.8, 95% confidence interval = 1.1-2.9). The major limitations of this study involve the ascertainment and classification of exposures to trihalomethanes, including such issues as the imprecision of using aggregate municipal measures for classifying exposure at the level of the individual, the potential misclassification due to residential mobility, and the fluctuation of trihalomethane levels.     

Persistent pesticides in human breast milk and cryptorchidism

INTRODUCTION: Prenatal exposure to some pesticides can adversely affect male reproductive health in animals. We investigated a possible human association between maternal exposure to 27 organochlorine compounds used as pesticides and cryptorchidism among male children. DESIGN: Within a prospective birth cohort, we performed a case-control study; 62 milk samples from mothers of cryptorchid boys and 68 from mothers of healthy boys were selected. Milk was collected as individual pools between 1 and 3 months postpartum and analyzed for 27 organochlorine pesticides. RESULTS: Eight organochlorine pesticides were measurable in all samples (medians; nanograms per gram lipid) for cases/controls: 1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene (p,p -DDE) : 97.3/83.8; beta-hexachlorocyclohexane (beta-HCH) : 13.6/12.3; hexachlorobenzene (HCB) : 10.6/8.8; alpha-endosulfan: 7.0/6.7; oxychlordane: 4.5/4.1; 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (p,p -DDT) : 4.6/4.0; dieldrin: 4.1/3.1 ; cis-heptachloroepoxide (cis-HE) : 2.5/2.2. Five compounds [octachlorostyrene (OCS); pentachlorobenzene, 1,1-dichloro-2,2-bis(4-chlorophenyl) ethane(p,p -DDD) ; o,p -DDT ; mirex] were measurable in most samples (detection rates 90.8-99.2%) but in lower concentrations. For methoxychlor, cis-chlordane, pentachloroanisole (PCA), gamma-HCH, 1,1-dichloro-2-(2-chlorophenyl) -2,2(4-chlorophenyl) ethane, trans-chlordane, alpha-HCH, and o,p -DDE, both concentrations and detection rates were low (26.5-71.5%). Heptachlor, HCH (lc delta, epsilon), aldrin, beta-endosulfan and trans-heptachloroepoxide were detected at negligible concentrations and low detection rates and were not analyzed further. Seventeen of 21 organochlorine pesticides [p,p -DDT, p,p-DDE, p,p-DDD, o,p-DDT, HCH (alpha, beta, gamma), HCB, PCA, alpha-endosulfan, cis-HE, chlordane (cis-, trans-) oxychlordane, methoxychlor, OCS, and dieldrin] were measured in higher median concentrations in case milk than in control milk. Apart from trans-chlordane (p = 0.012), there were no significant differences between cryptorchid and healthy boys for individual chemicals. However, combined statistical analysis of the eight most abundant persistent pesticides showed that pesticide levels in breast milk were significantly higher in boys with cryptorchidism (p = 0.032). CONCLUSION: The association between congenital cryptorchidism and some persistent pesticides in breast milk as a proxy for maternal exposure suggests that testicular descent in the fetus may be adversely affected.     

Relation between concentration of lead, zinc and lysozyme in placentas of women with intrauterine foetal growth retardation

Intrauterine foetal growth retardation (IUGR) implies increased risk of morbidity and mortality of the newborn. Aetiology of intrauterine retardation is probably multifactorial and may include maternal infection, malnutrition, placental dysfunction, hypertension, toxaemia, smoking, professional and environmental exposure. The work concentrates on the lead, zinc and lysozyme levels in blood and placental tissues of 50 females in the IUGR group and 43 females from a control group. Statistically significant differences in zinc and lead levels between the compared group were found. The IUGR group had lower zinc and higher lead levels. A significant negative correlation of zinc and lead levels was observed. We found a statistically significant relationship between lead levels in placental tissues and the age of the pregnant women. Higher age is associated with higher lead levels in placental tissue, whereas zinc levels decrease. In placental tissues of pregnant females of the IUGR group higher lysozyme levels were found. On the basis of the discussed results the authors recommend zinc supplementation during the pregnancy.     

Diarrhea and growth retardation

We have used a 38‐year data set from an Aboriginal community in Queensland, Australia to test whether diarrheal disease (D&V) leads to growth retardation. During this period the community has passed from the high‐birth‐rate/high‐death‐rate situation of developing countries to the “western” pattern. In children aged from birth to five years episodes of D&V were not associated with significant decrease in weight growth either in the “developing” or the “developed” period. D&V explained less than 1% of the variability in weight gain. The 1982–83 cohort showed that D&V accounted for only 4% of the variation in height and 1% of the variation in weight at 5 years. Frequent D&V and delayed growth are more likely to be due to common preceding factors rather than D&V causing delayed growth.     

Intra-uterine growth retardation: etiologic factors and management

OBJECTIVE: The aim of this study is to define the etiologic factors, the diagnostic proceduresand obstetrical rules to be observed during a pregnancy in relation with low birth weight. PATIENTS AND METHODS: This is a retrospective study of 124 cases, carried out at the military hospital of Tunis, between January 1st 1999 and December 31 st 2001. RESULTS: The frequency of intra-uterine growth retardation (IVGR) was 2.1%. 46.8% of the patients were primiparous. The mean age of the patients was 30 years. 25.8% of the patients developed toxemia. The etiology was predominantly renovascular-syndromes, urinary infections, and idiopathic hypotrophy. The positive diagnosis was suggesred by the measure of the uterine height in 96% and was confirmed by sonogaphy in all cases. The ombilical Doppler was pathological in 17.76% of the cases. A corticosteroid administration for pulmonary maturation was prescribed in 28% of the cases. Obstetrical common rule was fetal extraction: 42.7% of the patients were delivered by cesarean. CONCLUSION: There is a real need to insist on the importance of early detection of fetal hypotrophy and of better management of the women at risk.     

The effect of s-triazine-type pesticides and chlorinated hydrocarbons on lactate dehydrogenase

The effect of pesticides on nontarget organisms was studied by following their effect on enzymes from these organisms in vitro. s-Triazines substituted in positions 2, 4, and 6 behaved as inhibitors of plant and animal lactate dehydrogenase, acting competitively with respect to the coenzyme. The inhibition constants were of the order of 10(-3) M and the structure of the substituents exerted no pronounced effect on the inhibition type and the value of the inhibition constant. Polycyclic chlorinated hydrocarbons were found to be much stronger inhibitors, with inhibition constants of the order of 10(-5) M. These substances inhibit the reaction catalyzed by lactate dehydrogenase not only by reaction with the enzyme, but also by a probable direct reaction with the coenzyme.