Prevention of preterm births: a perinatal study in Haguenau, France

A reduction in preterm births has been observed in Haguenau (Eastern France) during a 12-year intervention study with a program for prevention of preterm deliveries. The Perinatal Study of Haguenau was an observation tool used in a stable population, and it allowed measurement of the way women have progressively responded to the new proposals in prenatal care. It also allowed measurement of the results of the interventions: low birth weight (less than 2,500 g) and preterm birth rates (less than 37 weeks of gestation) among single live births. The total duration of the study was divided into three periods of four years (1971 through 1974, 1975 through 1978, and 1979 through 1982), for which the numbers of single live births are 5,763, 4,957, and 5,919, respectively. For the same periods, the low-birth-weight rates, 4.6%, 4.0%, and 3.8%, respectively, showed a significant decrease (P less than .001). Following a similar pattern, the rates of preterm birth were 5.4%, 4.1%, and 3.7% (a significant reduction with P less than .001). These improvements in pregnancy outcome do not disappear after standardization of mother's age, high blood pressure, or social class distribution. These findings, which concur with the results of others, enhance the hypothesis of a direct relationship between a prevention program and a reduction in preterm birth rates.

Multicentred controlled trial of cervical cerclage in women at moderate risk of preterm delivery

A total of 506 women at moderate risk of preterm delivery were randomly allocated to either cervical cerclage or a control group. Significantly more women in the group allocated to cerclage were admitted to hospital for reasons other than the operation and more received oral tocolytic drugs. There were also more caesarean sections and more preterm deliveries in the women allocated to cerclage although the differences between the two groups were small and not statistically significant.

Prematurity and occupational activity during pregnancy

The aim of this study was to determine the elements of fatigue in occupations which constitute possible risk factors for the course of a pregnancy, and, in particular, that could cause premature birth. In 1977-1978, a total of 3437 women in France were surveyed after giving birth in two maternity hospitals. One hospital was located in Lyon (a large city) and the other in Haguenau (a small town). Among 1928 working women, it was found that certain occupational categories are more prone to risk of prematurity than others. The authors carried out an analytical breakdown of the job into its diverse components which led them to define five sources of fatigue and to construct an index capable of detecting the strenuous working conditions. There is a significant relationship between the prematurity rate and the number of high fatigue scores observed in the job. When the number of scores varies from 0 to 5 the rate of premature births increases from 2.3% to 11.1%. This relationship remains significant after controlling for confounding factors.

Maternal factors associated with small-for-dateness among twins

The maternal risk factors that correlate with small-for-dateness among twins have been analyzed using a sample of 659 twins pairs and a matched sample of singletons. Non-marital status, job involvement, and the previous delivery of a low-birth weight (less than 2,500g) infant present a negative interaction with twinning, as low gestational age-adjusted birth weight does not correlate significantly with these risk factors among twin gestations, while it does among singleton gestations. On the other hand, the effects of parity, habitual maternal weight, smoking during pregnancy, and twinning are additive on gestational age-adjusted birth weight. Indeed, the decrease in adjusted birth weight associated with these risk factors is of the same magnitude among twins and singletons and is statistically significant in both cases. These findings suggest that exposure of twin pregnancies to these latter risk factors, and particularly to smoking during pregnancy, can lead to the delivery of newborns with extremely low birth weights.

Twinning following oral contraceptive discontinuation

The characteristics of 673 mothers of twins were compared to those of a matched sample of mothers of singletons. Both groups of mothers were interviewed just after delivery, and births in each group were matched for time and place. Of the characteristics studied, the use of oral contraceptives (OC) displayed a significant negative association with dizygotic twinning, with an estimated relative risk of 0.55 (95% confidence limits: 0.39/0.78). Among other maternal trails significantly associated with dizygotic twinning, ony age, parity and weight were possible confounders as far as the relationship between OC use and dizygotic twinning was concerned. Adjustment for these 3 characteristics left this relationship unaltered. These findings are compatible with the existence of the a direct relationship between OC use and a reduction in dizygotic twinning. Review of the available evidence concerning reproductive capacities following OC discontinuation suggests that the higher incidence of chromosomic abnormalities among spontaneous abortuses of OC users or their lower fertility could explain a reduction of dizygotic twinning rate after OC discontinuation. It is concluded that examination of te time and place variations in OC use and dizygotic twinning would help to clarify the nature of their relationship.

Comparison of two successive policies of cervical cerclage for the prevention of pre-term birth

The percentage of women receiving cervical cerclage increased from 5% to 18% between two periods at Haguenau maternity hospital, according to a new policy for the prevention of pre-term birth. A parallel reduction of premature deliveries by about a half was observed in the relevant group of women. This suggests that cerclage might be employed on another basis than is currently the case, and that a randomized trial is urgently needed to define its indications more precisely.

[Analysis of the geographical variations of twinning rate in France. An indirect approach to study spontaneous abortions (author's transl)]

The hypothesis of the existence of spatial variations of spontaneous abortion rates has two logical consequences on dizygotic twinning rates: they must be heterogeneously distributed and show a positive correlation with natality. French data available on dizygotic twinning rates from 1950 to 1974 are in agreement with both implications. Although alternative explanations are possible, these findings do reinforce the relevance of dizygotic twinning rate variations as a tool for the assessment of reproduction failures.

[Organic micropollution of drinking water]

This work is about organic micropollution of waters sampled at the flowing in and out of three treatment stations. Micropollutants are obtained by chloroformic extraction. It is shown that the extracts have biological effects which can be measured by in vitro and in vivo assays. The treatments reduce the total amount of extractible substances but they induce modifications in their chemical composition and their biological activity. These observations allow to precise how the problem of an eventual health effect of organic micropollution could be approached.

Spontaneous abortions in sibship of children with congenital malformation or malignant disease

Parents of 751 children affected by cancer/leukemia, congenital heart disease, strawberry nevus or mental retardation have been investigated with respect to their reproductive history and their exposure to risk factors for spontaneous abortion. Differences between the four groups were established for the number of children in the sibship, the proportion of multigravidae and the spontaneous abortion rate among these women. The greatest differences were observed in the two groups of malformed children compared with the other two groups, being as marked in those with a severe malformation (heart defect) as in those with a benign one (strawberry nevus). Taking known risk factors for spontaneous abortion into account did not explain the observed differences. An etiological hypothesis is put forward which takes account of the high proportion of quantitative abnormalities of the karyotype associated with congenital heart disease and spontaneous abortion.

[Water hardness and cardiovascular mortality. Discussion of evidence from geographical pathology (author's transl)]

The existence of a significant negative correlation between hardness of drinking water and mortality rates from cardiovascular disease has been established by numerous authors. The intensity of this relationship varies according to the country concerned, the size of the areas studied, and the confounding factors taken into consideration. Nevertheless, the problem concerning the interpretation of the correlation has not yet been resolved. In particular the methodological problem resulting from the contiguity of the geographic units has been generally neglected. It is shown that these difficulties weaken the conviction that the relationship is a causal one.

[Sero-epidemiology of infections due to cytomegalovirus by indirect hemagglutination technic]

Applied to cytomegalovirus, the technique of indirect hemagglutination offers a good sensitivity and reliable specificity for serological testings. Improvements in the standardization are however still required. Sero-epidemiological studies performed in different groups of children and carried out with this method led to the following results: mother-child contagium, early infection in young infants, and influence of socio-economical and ethnical factors. Studies performed on pregnant women showed that the risk of infection decreased after the first pregnancy.

[Effects of spontaneous abortions on the frequency of births of twins]

The frequency of spontaneous abortion of one zygote after double ovulation-fertilization makes it possible to explain some of the main features of the dizygotic twinning rate, namely the sharp decrease of this rate at higher maternal ages after its regular increase up to 35 years, and also the secular tendancy of this rate to decrease, observed in many countries. The consequences of these findings are discussed, in particular those which are related to the etiology of spontaneous abortion and mongolism, and to the frequency of multiple ovulation.

Retrospective and prospective epidemiological studies of 1500 karyotyped spontaneous human abortions

Epidemiologic studies, retrospective and prospective, were done on 1500 abortions collected from 1966-1972. No secular or seasonal variations were observed. From the analysis of the relative frequencies of the different types of chromsome anomalies it is estimated that 1 out of every 2 conceptions has a chromosome anomaly. Maternal-age influence was found only for the autosomal trisomy group, mainly D and G trisomies. No effect of oral contraceptives were discovered. An increased frequency of chromosome anomalies occurred after ovulation-inducing therapy and after occupational exposure of the father to irradiation. No variations in the fertility rate and in the frequency of congenital malformations in births following abortions was noted. The incidence of recurring abortion was mainly influenced by the reproductive history of the couple before the karyotyped abortion.

Individual correction of birth weight for parental stature with special reference to small-for-date and large-for-date infants

The aim of the present paper is to determine how parental stature measurements should be used to "correct" birth weight in order to improve the diagnosis of small or big-for dateness. A first approach, based on the pattern of coefficients of correlation between maternal and paternal weight and height, and birth weight (Tab. I), may be criticized for two reasons: 1) it does not take into account the possible variations of this pattern of correlations from one subcategory (for instance of age) of the sample to another and ii) it makes no difference between "genetic" and "environmental" components of parental influence on birth weight. A second approach takes into account the variations of parental stature measurements, of birth weight and of the pattern of correlations according to mother's age (Tabs. II and III). Briefly: The correlation between birth weight and mother's weight increases, the correlation between birth weight and father's weight decreases when mother's age increases (except for mother's older than 34), and these coefficents have the same value in the youngest group (mothers less than 21). These observations are consistent with the hypothesis of the predominance of the "genetic" component in the youngest group, which leads to the establishment of the coefficients to apply to each parental stature measurement by means of a multiple regression analysis carried out on this only group (Tab. IV). For the whole population, the correction must finally be calculated using the weights of parents at 20 years (or, if unknown, an approximate value). The correction is about ten grams per kilogram of mother's and eight grams per kilogramm of father's weight deviations from the mean values of the population to which they belong.