Possible interplay between vitamin C deficiency and prolactin in pregnant women with premature rupture of membranes: facts and hypothesis

The precise etiologic mechanisms involved in the premature rupture of membranes (PROM) during pregnancy, the main cause of preterm delivery worldwide, are unknown. Previous studies have shown that: (a) the rupture of chorioamniotic membranes is related to an imbalance between synthesis and degradation of collagen induced by the overexpression/activity of various matrix metalloproteinases (MMP); (b) during human labor and delivery the expression of prolactin receptors (PRL-R) increases in chorioamniotic membranes, decidua and placenta; (c) prolactin (PRL) can influence the synthesis of prostaglandins, the expression of some MMP (MMP-2, MMP-9 and decysin) and tissue inhibitors of MMP in general; (d) vitamin C deficiency induces the expression/activity of extracellular MMP and is considered a risk factor for PROM; and (e) vitamin C potentiates the dopamine-mediated inhibition of PRL in rats. The present hypothesis proposes that a decreased hypothalamic dopaminergic tone-and thus an increased synthesis/release of pituitary PRL - is induced by vitamin C deficiency below a critical threshold (<18 microg/10(8) leukocytes) and that both factors, in turn, would cause upregulation of the expression/activity of several MMP. The increased PRL concentrations (acting like a Th1-type cytokine) along with the overexpression of other proinflammatory cytokines would induce a premature switch from a favorable Th2-type immune response to a noxious Th1-type immune response in the intrauterine environment. This change, in conjunction with the upregulation of MMP-2 and MMP-9, would cause a premature imbalance between synthesis/degradation of collagen in chorioamniotic membranes (an "anticipation" of the normal parturition cascade?), which favors extracellular matrix degradation, proposed as the most relevant event in the genesis of PROM. This hypothesis represents a new dimension in the study of the etiology of PROM.

Collagen synthesis during pregnancy, vitamin C availability, and risk of premature rupture of fetal membranes

OBJECTIVE

To examine the relationship between plasma and leukocyte concentration of ascorbic acid and collagen type I propeptide C during pregnancy and subsequent premature rupture of membranes (PROM).

METHODS

Fifteen women with PROM and 26 controls were compared for plasma and leukocyte concentration of vitamin C and for Pro-C during pregnancy.

RESULTS

A statistically significant difference in maternal leukocyte ascorbic acid concentration was found between the two groups at week 28 of gestation (P50 was 16.90 for PROM group vs. 21.46 for control group; P>0.05). Increased risk for PROM (odds ratio, 10.99; 95% confidence interval, 2.40-49.91) was found with elevated concentrations of Pro-C at week 16 of gestation.

CONCLUSIONS

A higher rate of collagen synthesis early in pregnancy was demonstrated in PROM cases. However, no correlation with ascorbic acid availability was found. This study supports the findings of others that collagen metabolism disturbances are associated with PROM.

[HIV-1 virus transmission through maternal milk]

Human immunodeficiency virus type 1 (HIV-1) may be vertically transmitted during the pre, peri or postpartum period. Postnatal transmission as well as an increased risk of vertical transmission with breastfeeding has been shown for HIV-1 in several reports. Breastfeeding was here analyzed as a risk of HIV-1 transmission in a group of infants born to HIV-1 infected mothers. Among the 215 children studied in our population a significant difference was detected between those who were breastfed vs those who were bottle fed and finally became infected (p < 0.000000, R.R. = 4.29). We also report the case of a postnatal infection in a baby born to an HIV-1 seropositive father and a seronegative mother. Due to the risk of infection of the mother she had been thoroughly controlled when pregnant and after delivery. Mother and child were negative when retested at delivery, and at 10 months post-partum. At the age of 32 months the child attended the outpatient clinic with generalized lymphadenopathy and right parotitis. HIV-1 infection was then confirmed in both mother and child. At that time it was discovered that the baby had been breastfed up to the age of 24 months. This is the first reported child in Argentina whose infection may undoubtedly be attributed to breastfeeding.

Depression and body fat deposition in Mexican pregnant adolescents

BACKGROUND

The objective of this study was to assess the effect of maternal depressive symptomatology on fat deposition in a group of pregnant adolescents.

METHODS

A case-control study was performed with 85 pregnant women (45 adolescents and 40 adults) who attended a prenatal care course at a teaching hospital in Mexico City. During the second and third trimesters of gestation, a test proposed by Zung was applied to measure depressive symptoms. Weight and skinfolds (i.e., triceps, biceps, suprailiac, subscapular, and thigh) were measured in all women beginning at week 20 of gestation through 4 weeks postpartum. Monthly evaluations were performed.

RESULTS

At the 28th week of gestation, nearly 40% of pregnant adolescents showed scores above the cut-off points in the depression test, while among the adults this proportion corresponded to 15%. In the adolescents, depression status was related to self-esteem. Percentage of body fat in adult women tended to be relatively constant, while in adolescents a tendency toward increased body fat was found. In adolescents, depressive symptomatology and especially lack of self-esteem and weight gain during pregnancy were the variables that better predicted the fat-increment pattern during gestation, while in adults no variable was found that predicted fat deposition.

CONCLUSIONS

Depression status is a risk factor for excessive fat deposition during pregnancy in Mexican adolescents.

[Serum retinol in urban Mexican women during the perinatal period]

OBJECTIVE

To establish the prevalence of vitamin A deficiency during pregnancy and lactation in a group of urban Mexican women.

MATERIAL AND METHODS

A group of pregnant women who attended a prenatal care program were invited to participate. Subjects had no added pathologies and were less than 20 weeks pregnant. Evaluations were performed 3 times during pregnancy until 24 weeks post-partum. Vitamin A levels were determined in serum by high performance liquid chromatography (HPLC). The cut-off point to consider retinol deficiency was < 1.05 mumol/L.

RESULTS

During the 3 gestational evaluations, vitamin A levels were 2.34 +/- 0.70, 2.41 +/- 1.03 and 1.86 +/- 0.66 mumol/L, respectively, which shows a significant decrease. However, only 1/30 was situated below the accepted cut-off point to consider risk of deficiency, and none for deficiency. During post-partum, concentrations remained relatively constant, approximately 2.10 mumol/L. Lactation had no impact on serum retinol levels, while weight loss did.

CONCLUSIONS

No cases of vitamin A deficiency were found in the studied population during the perinatal period. Maternal weight loss affects post-partum retinol levels.

[Development and evaluation of food supplements for the education, health, and nutrition program]

OBJECTIVE

To develop and evaluate nutritional supplements destined to a program of social assistance.

MATERIAL AND METHODS

In the design of the nutritional supplements a series of criteria were considered including nutrient composition, physicochemical properties and feasibility of production and utilization. Final products were initially evaluated to determine the level of acceptance in 40 children, 52 pregnant women and 62 lactating women in Mexico City. A community trial was also carried out to determine acceptance and consumption in 108 children and 128 women from a rural community in the state of Morelos.

RESULTS

The specific formulation and technical processes of production of the nutritional supplements are presented. Products proved to be widely accepted, with average scores of 4.11-4.29 for the children's beverage, and 3.98-4.15 for a more viscous pap (range of scores was 1 to 5). Products for women received average scores from 4.75 to 5.70 in pregnant and from 4.8 to 5.4 in lactating women (range of scores from 1 to 7). In the community trial, supplements were very well accepted. Average consumption was > 75% among children and > 98% among women. Mean energy intake from supplements was 244 Kcal/day for women, and for children, 168 Kcal/day with the pap and 147 Kcal/day with the beverage. Consumption was consistent in all cases along the study.

CONCLUSIONS

Nine nutritional supplements were developed and evaluated which comply with the necessary nutritional, physicochemical and hygienic characteristics for the target population, besides being relatively simple to prepare, and widely well accepted and consumed.

[Non-pregnant women's nutrition and its impact in life quality]

Emphasis is made in the nutrition aspects related to women at reproductive age that are not pregnant or lactating and that includes the variations that happen throughout the menstrual cycle, fluctuations in energy expenditure, body composition and mood. Nutrition role in some premenstrual syndrome alterations as premenstrual stress (serotonin, magnesium, calcium and vitamin E), anemia, gynecological cancers (antioxidants, alcohol, folic acid, lipids, fiber and phytosterols) and osteoporosis (exercise and diet) are also described, as well as the impact on nutrition of the use of contraceptive methods (hormonal and intrauterine devices). Practical recommendations directed toward the evaluation and management of the main nutrition needs of adult women are included.

[Clinical nutrition training in medical schools of Mexico]

OBJECTIVE

To describe the efforts carried out to strengthen nutrition education in Mexican medical schools. Emphasis was placed on the status previous to the program implementation, the design of a new basic curriculum, and the description of the main program strategies implemented.

METHODS

a) Analysis of available medical curricula; b) Application of a questionnaire to the school deans; c) Assessment of knowledge of nutrition of advanced medical students; d) Design of a basic curriculum of clinical nutrition; e) Edition of a textbook; f) Design and implementation of program strategies to strengthen nutrition education.

RESULTS

Clinical nutrition was not a topic included in most curricula analyzed and, when present, it was incorporated to related clinical subjects. Usually, emphasis was placed on basic topics of nutrition while clinical and applied subjects were considered less frequently. Lack of a specialized faculty and weakness of teaching infrastructure were some problems identified. A basic curriculum adaptable to different contexts was designed, and a textbook on clinical nutrition was edited and published. Training and formation of nutrition specialists were among the key programs implemented.

Modulation of 72-kilodalton type IV collagenase (Matrix metalloproteinase-2) by ascorbic acid in cultured human amnion-derived cells

Extensive research has been done to investigate the effects of nutrients on placental and fetal development. It is now evident that environmental factors such as diet may exert a profound effect on gene expression during pregnancy. A low intake of vitamin C during pregnancy has been linked to a higher risk of premature rupture of the membranes (PROM) because of its well-known role in collagen biosynthesis. Here we report a new effect of ascorbic acid acting as a modulator of the 72-kDa type IV collagenase (matrix metalloproteinase-2; MMP-2). MMP-2 expression/activity is down-regulated by vitamin C in human amnion cultured cells. The regulatory effect is exerted at the transcriptional level and is specific for MMP-2. Matrix metalloproteinases are implicated in tissue remodeling, and our results allow us to suggest a molecular mechanism that relates poor availability of vitamin C during pregnancy and the development of PROM.

Counselling following diagnosis of a fetal abnormality: comparison of different clinical specialists in Mexico

Most geneticists agree that counselling should be nondirective, and studies report that genetic counselling by geneticists is performed largely in a neutral style. However, couples at risk of having a child with a genetic condition may seek the advice of other physicians. The purpose of the present study was to describe the answers of four groups of specialists from Mexico City (internists, pediatricians, obstetricians, and neurologists) regarding how they would counsel a couple when prenatal diagnosis has shown that a fetus is affected by one of 17 different genetic disorders and to analyze the role of several variables in the development of their opinion. Our results show that physicians in these specialties are more likely to counsel directively than neutrally. Other variables did not influence the directiveness. With respect to direction of influence, internists, pediatricians, and neurologists are more likely to counsel terminating affected pregnancies than are obstetricians (P = 0.0002). Similarly, clinicians older than 37 years of age and those reporting that religion is not important to them counsel terminating affected pregnancies (P = 0.005 and P = 0.003, respectively). Physicians' gender and clinical experience with genetic diseases did not show statistically significant differences. Strong consensus among specialists was reached only on terminating pregnancies in anencephaly. A lowered and moderate consensus (51-75% agreement) was reached on continuing pregnancies with cleft lip and plate. A moderate measure of consensus for nondirective counselling was found among obstetricians regarding 14 of the 17 diseases in the study, whereas neurologists expressed a moderate measure of consensus on counselling the termination of pregnancies when the fetus was affected by neurological disorders. Hence, the approach to counselling was related in part to the fetal condition and in part to the clinician's specialty and age and the self-reported importance of religion. The data presented herein may not be representative of all Mexican physicians within the selected specialties; however, it is important to gather their opinions because they are involved in the care and treatment of genetic diseases and may have an important influence on the demand and availability of prenatal diagnosis and abortion.

Attitudes of Mexican physicians toward induced abortion

The objective of this study was to analyze physicians' attitudes towards induced abortion with normal fetuses and fetuses known to have an abnormality in various degrees. A total of 193 physicians (internists, pediatricians, gynecologists and neurologists) answered a self-administered questionnaire. The questions were about voluntary abortion; voluntary abortion with malformed fetus; abortion because the fetus has anencephaly; and two questions were asked for the use of prenatal diagnosis and abortion in case of the fetus being the physician's child. The majority of physicians were male, over 35 years, religious and did not have experience with genetic diseases. Few physicians approved abortion of a normal pregnancy, 6 out of 10 agreed if the fetus was malformed, and this number increased to 8 or 9 out of 10 in cases of severe or lethal genetic disease. Gynecologists and neurologists were less in agreement with abortion when pregnancy is normal than the internists and pediatricians (7% vs. 20%). In general the physicians did not have consistent answers. Agreement for abortion was influenced by religious values.

HIV-1 and hepatitis B virus infections in adolescents lodged in security institutes of Buenos Aires

The goal of this study was to determine the prevalence of human immunodeficiency virus type 1 (HIV-1) and hepatitis B virus (HBV) infections in street youth lodged in security institutes, from February 1992 to March 1995, to correlate these infections with nontherapeutic drug use, and to compare these results with a previous study done in a similar population. A total of 1460 white adolescents, 276 females and 1184 males, were enrolled (mean age 16.6 years). Prevalence of HIV-1 was 4.58% and of HBV was 6.78%. The prevalence of dual HIV-1/HBV infection was 1.91%; the prevalence of HBV infection was significantly higher in HIV-positive subjects (p < 0.0000000, chi 2 = 136.17, OR = 13.37) than in those not infected with HIV-1. Prevalences were higher in males. Intravenous drug addiction proved to be a significant risk factor for both viruses (HIV-1, p < 0.0000000, chi 2 = 171.34, OR = 16.84; HBV, p = 0.000044, chi 2 = 16.67, OR = 3.17); 6.43% of the total population were intravenous drug users. Comparison of the current results with our previous study (1989-1992) showed that the prevalence of HIV-1, HBV, and concurrent HIV/HBV as well as intravenous drug addiction has decreased significantly in our current cohort (chi 2 = 134.85, p < 0.0000000; chi 2 = 126.62, p < 0.0000000; chi 2 = 110.05, p < 0.0000000; and chi 2 = 158.3, p < 0.0000000) respectively. Progress appears to have been made in the fight against acquired immunodeficiency syndrome (AIDS), and promising results have been obtained. However, if further viral spread is to be avoided, the emphasis on prevention should be energetically maintained.

Parity and the prevalence of overweight

OBJECTIVE

To assess the association between previous term pregnancies and the prevalence of overweight in a group of urban women, controlling for the influence of age.

METHODS

One thousand twelve women, living in middle and low socioeconomic areas of Mexico City, were interviewed at home and their reproductive histories studied. Height and weight were measured in a clinical setting using controlled procedures. Overweight (BMI > 25) was the dependent variable used to calculate odds ratios and to perform a multiple logistic regression analysis.

RESULTS

Age and parity were significantly associated with the prevalence of overweight. Controlling for age, two or more previous pregnancies significantly increased the magnitude of the association.

CONCLUSION

During the reproductive years parity seems to increase the risk of overweight in low and middle socioeconomic level urban women.

Weight gain during pregnancy in adolescents: evaluation of a non-nutritional intervention

The goal of the present work is to report the impact of psychological support, given during pregnancy to a group of adolescents, on maternal weight gain and their infants' birth weight. A total of 54 clinically healthy pregnant women of middle educational level were studied in Mexico City, beginning on the 20th week of pregnancy throughout the end of it. Before pregnancy there were no significant intergroup differences in height, age at menarche or expected weight for height; the groups were adolescents without psychological support (group I), adolescents with support (group II), and adults (group III). The median weight gains were 8.2, 11.0 and 12.2 kg for groups I, II and III respectively. Our results suggest that in favorable socioeconomic conditions, psychological support can be a non-nutritional intervention which can promote an adequate weight gain during pregnancy in adolescents, probably by diminishing their anxiety level.

Incidence of premature rupture of membranes in pregnant women with low leukocyte levels of vitamin C

The present study was undertaken to explore the association between vitamin C nutritional status in pregnant women with premature rupture of the chorioamniotic membranes (PRM). A case-control cross-sectional study was carried out in 10 women with PRM and 19 women without PRM. The women were evaluated in the first hours postpartum while hospitalized: 10 ml of blood were obtained from each woman to determine vitamin C expressed as micrograms/10(8) leucocytes or microgram/mg of leucocyte protein. Data on fruit and vegetable consumption was collected by a frequency dietary survey and the hospital clinical records were reviewed to obtain their obstetric history and data on the presence of infection during pregnancy, in placenta and/or in fetal membranes. Low vitamin C levels were considered at a cut-off point equal or less than 26.33 micrograms/10(8) leucocytic cells and 3.15 micrograms/mg leucocyte protein. An association was found between low vitamin C levels and cases with PRM. No difference was found in the frequency of consumption of fruit and vegetables between the two groups. Infections were more frequently found in the PRM group, when the women had low levels of vitamin C, and when both risk factors were present simultaneously the proportion of PRM cases identified was greater than 0.75.

[Knowledge on nutrition among medical residents]

We evaluated the knowledge on nutrition of physicians undertaking their residency in gynecology, pediatrics or internal medicine. A group of nutrition students was also evaluated for comparison. We used a "don't know-false-true" type of examination. The mean grades of the physicians were lower than those considered minimum for approval, whereas the mean grades of the nutrition students were near the minimum for approval.

Biotin deficiency in protein-energy malnutrition

Several of the clinical and biochemical manifestations of biotin deficiency also occur in severe protein-energy malnutrition (PEM). Average plasma biotin concentrations were lower in 16 malnourished children (10 with marasmus, 3 with kwashiorkor and 3 with marasmic kwashiorkor) than in 31 controls. Lymphocyte mitochondrial carboxylase activities were studied in 11 controls and in 10 patients with PEM; on the average, they were lower in the patients. Their activation indices (the ratio of enzyme activity in cells incubated with biotin to activity in cells incubated without the vitamin) were higher in PEM. All these differences were statistically significant. None of these parameters were age-dependent in a range between 3 and 72 months. Carboxylase activities and plasma biotin levels increased to normal during nutritional recovery in two malnourished patients who were further studied. These results suggest that there is biotin deficiency in severe PEM. Urinary biotin concentrations, expressed per g of creatinine, were higher in the patients than in the controls; this may have been caused by increased renal clearance or by the reduced creatinine excretion which occurs in malnourished individuals. It will be important in future studies to determine the relative contribution of biotin deficiency to the malnourished phenotype.

Placentas of small-for-dates infants: a small controlled series from Mexico City, Mexico

Thirty-five placentas of small-for-dates infants were compared with control placentas of normally grown infants. They were small by weight, area, and volume and tended to have a marginal cord insertion; marginal cord insertion was associated with a thick cord, and central insertion, with a thin cord. When the two groups were compared, the first showed increased fibrinoid deposits and atherosis, more severe fetal abnormalities, and abnormal nutrition in the mother, together with a high incidence of preeclampsia. In the mothers of both groups, peak diastolic blood pressure was lower than that in the control group; additional factors leading to a probable reduction in placental blood flow were different in the two groups.

[Social aspects of energy and protein consumption in a group of pregnant women]

This paper presents the results of a dietary survey (weighed intake/24 hr) carried out in 64 pregnant women living in Huamantla, Tlaxcala, Mexico and its proximities, during November 1973. The primary objective of the study was to identify social indicators with predictive value in relation to food consumption patterns, in order to detect groups at risk of having an inadequate intake. A subgroup of the women (15 cases) had adequate levels of energy and protein intake (E/P intake) when compared to the recommendations established by FAO/OMS, 1973, although they consumed a diet with relatively few variations which was also low in fat content. Family organization was the socioanthropological variable which had the greatest relationship with E/P intake. The extended families presented a better E/P ratio than the nuclear families. Interestingly, the per capita expenditure did not show a significant association with nutritional indicators. These data suggest, therefore, that in the population studied the E/P ratio is more closely associated with family organization than with its income level.