Aiming to show that delayed ovulation may induce MZ twinning, follicular maturation was induced in the rabbit by a small quantity of Pregnant Mare Serum Gonadotropin (16 UI four times): coitus, which induces ovulation in the rabbit, was delayed 60 hours after the last injection. From the 387 blastocysts obtained after this treatment, 6 (1.5%) were pairs of MZ twins, twinning being otherwise exceptional in the rabbit. Other anomalies were shown by the embryos, apparently related to a deficient quality of the eggs: high embryonic mortality (62% vs. 27% in controls) and chromosomal anomalies (20%) such as trisomies, triploidies, and chimaeras. The relation between MZ twinning, chromosomal anomalies, and embryonic mortality induced by delayed ovulation, could be connected and related to the poor perinatal conditions frequently observed in human MZ twins.
Diabetes, whether or not it is insulin deficient, is frequently associated with vascular complications during pregnancy. It is accepted nowadays that the uterine artery velocity waveform is predictive concerning pregnancy-induced hypertension (PIH) and its complications. It thus seemed interesting to analyse the predictivity of vascular complications of diabetes by using uterine artery velocity waveforms. We have thus explored 37 diabetic patients [group 1: insulin-deficient diabetes (IDD), n = 10; group 2: gestational IDD, n = 6; and gestational non-IDD, n = 21). We have found vascular complications for 10 patients, divided between all 2 groups: 2 preeclampsia, 2 fetal suffering before any labour, 2 cases of intra-uterine growth retardation (including a trisomy 18) and 5 PIH. The uterine artery velocimetry measurement has been found to be pathological 5 times, and always in patients who later developed vascular complications. Among this selected population and excluding the trisomy 18, the sensitivity is of 44.5%, the specificity of 100%, the positive predictive value of 100%, and the negative predictive value of 84.3 %. If these results are confirmed, this examination could be an excellent marker of the vascular risk and thus would have its place during systematic survey of pregnancies complicated by diabetes.
A total of 116 cases of multiple pregnancy has been observed in a 5-year period. MZ twin pregnancies appear to be significantly increased in the maternal age group 31-35. Also significant is the higher frequency of abnormal cycles in MZ twin pregnancies. Family incidence of twins is more significant in mothers of DZ as compared to MZ twins.
Statistical studies have shown a significant correlation between maternal pregestational weight and duration of pregnancy (i.e., a low weight may cause a shortening of pregnancy). Duration of pregnancy is further correlated to the weight gain (i.e., it is shortened by an insufficient gain). This phenomenon is observed in thin women, but not in women of heavy weight before the pregnancy.The studies of weight losses obtained through hypocaloric or sodium-free diets or diuretics, show that a sudden weight loss may cause a shortening of pregnancy duration. This is verified in patients with normal or insufficient weight gain and starting with a normal or small weight, but not in overweight patients or with an important weight gain.This study demonstrates the dangers of excessive measures toward prevention of toxemia. The decision of compulsive weight loss in mothers with multiple pregnancy must be well thought and carefully applied, for excessive measures could reduce the duration of pregnancy and thus increase the risks of perinatal death.
The effects of smoking by pregnant women on the progress of their pregnancy and the development of the fetus have been the subject of many studies [6,10,9,12]. The aims of the present work are to observe the effect of smoking on the mother's gain in weight during pregnancy and to contribute towards an answer in the present-day debate on the mechanism whereby smoking affectsthebirthweight of the child.
l Selection of the casesThe subjects of the present study were a group under study of 105 smokers and a control group of 100 non-smokers.
Curriculum
The study group.105 cases were selected from the total number of women attending the prenatal clinic regularly and the resulting births that took place at the Antoine Beclere Maternity Hospital in 1974. The women in the group smoked at least 10 cigarettes a day throughout their pregnancy. This was ascertained at the first attendance at the pre-natal clinic and was confirmed at the following attendances. Those patients who stopped smoking during pregnancy were eliminated from the study.
.2 The control group.This consisted of 100 women who did not smoke during pregnancy and who were chosen at random from the total number of non-smokers. The twin pregnancies were eliminated.
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