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

Vitamin C Levels in Pregnant Women and the Efficacy of Vitamin C Supplements in Preventing Premature Rupture of Membranes: A Systematic Review and Meta-Analysis

Background

Premature rupture of membranes (PROM) is defined as the leakage of amniotic fluid before the onset of labor and delivery contractions. Some studies found that women who experienced PROM had significantly lower vitamin C blood levels than those who did not, while others found no significant differences. Previous systematic reviews and meta-analyses on the efficacy of vitamin C in the prevention of PROM had conflicting results.

Aims

Conduct a systematic review and meta-analysis to determine if there was a significant difference in vitamin C blood levels in women who had PROM versus the control group who did not and to determine if vitamin C supplements could help prevent it.

Study Design

Systematic review and meta-analysis.

Methods

We registered our protocol with PROSPERO (CRD42022371644). We searched PubMed/MEDLINE, Web of Science, and Scopus through February 15, 2024. Additionally, backward and forward citation searches were conducted. Studies were selected based on predetermined inclusion and exclusion criteria. Meta-Essentials: Workbooks for Meta-Analysis (version 1.5) was used for analysis.

Results

Twenty-five studies (26 reports) met all eligibility criteria, with 18 studies (18 reports) assessing vitamin C levels and seven studies (eight reports) evaluating efficacy. Women with PROM, whether preterm or term, had significantly lower vitamin C levels [Hedges’ g, -1.48; 95% confidence interval (CI): -2.82, -0.14; p = 0.020; I2 = 94.08%) and specifically preterm PROM after removing the outlying study [Hedges’ g, -1.29; 95% CI: -1.85, -0.73; p < 0.001; I2 = 87.35%). Vitamin C supplementation significantly reduced the risk of preterm or term PROM [risk ratio (RR), 0.57; 95% CI: 0.39, 0.81; p < 0.001; I2 = 12.17%), particularly for preterm PROM (RR, 0.67; 95% CI: 0.45, 0.99; p = 0.001; I2 = 0.00%). There were no significant differences in vitamin C levels between women with term PROM and controls, and there were no differences in the risk of developing term PROM between women taking vitamin C supplements and controls. Results were not robust in all sensitivity analyses.

Conclusion

Women with PROM, particularly those who developed it preterm, appear to have significantly lower vitamin C levels, and vitamin C supplementation appears to be effective in reducing the risk of PROM, particularly preterm PROM. More high-quality studies with low risk of bias, more homogenous, and larger samples are needed to confirm these findings.

The relationship between the latency period, infection markers, and oxidant and antioxidant states in women with preterm premature rupture of membranes

BACKGROUND

A major cause of perinatal morbidity and mortality has been reported to be preterm premature rupture of membranes (PPROM). Our objective was to evaluate oxidant-antioxidant balance, infection parameters, time interval between rupture of membranes and delivery (latency period), and the relationship among all these parameters.

METHODS

Seventy-five cases with PPROM between 24 and 34 gestational weeks were included in the study. A control group of 41 women who gave birth at term were considered as the control group. The relationship among maternal plasma total oxidative stress (TOS), malondialdehyde (MDA), total antioxidant status (TAS), leukocyte counts, CRP, vitamin C and E levels, gestational week, neonatal birthweight, and latency period was evaluated.

RESULTS

In cases with PPROM, rupture occurred at an average of 29.4 gestational weeks and premature babies were born at an average of 31.6 gestational weeks. The mortality rate of babies born to PPROM women was 18.7% (14/75) died at or following birth. In the PPROM group, TOS, MDA, and leukocyte counts were found to be significantly higher compared to the control group (p < 0.001). Besides, a significant negative correlation was detected among the latency period, TOS, CRP, and leukocyte counts (p < 0.05).

CONCLUSIONS

Appropriate treatment protocols that strengthen antioxidant defense systems and taking into consideration the signs of infection can decrease the incidence of PPROM and/or mortality rates of babies born to PPROM women.

Ascorbic Acid concentration and preterm premature rupture of membranes

INTRODUCTION

Preterm premature rupture of membranes (PPROM) complicates 1-5 % of all pregnancies and is the major contributory factor for perinatal morbidity and mortality. Micronutrient deficiency (vitamin C) is associated with increased risk of PPROM. This study was conducted to establish the association between maternal plasma vitamin C concentration in women with PPROM and women without PPROM and to study the difference in maternal morbidity, neonatal morbidity, and mortality.

METHODS

A prospective study was conducted where 40 women (20 in each study and control group) with singleton pregnancies between 28 and 37 weeks gestation were recruited. Women with anemia, diabetes, UTI, RTI, vaginal infection, bleeding, h/o PPROM in previous pregnancy, polyhydramnios, and smoker were excluded from the study. Maternal plasma vitamin C levels were measured.

RESULTS

Ascorbic acid levels were low in women with PPROM 0.41 ± 0.08 versus 0.84 ± 0.19 mg/dl. There is a linear decline in plasma vitamin C levels as the pregnancy advances. Inverse relationship was observed between duration of rupture of membranes and vitamin C levels. There was a significant difference in maternal morbidity, neonatal morbidity, and mortality.

CONCLUSION

Ascorbic acid concentration was low in women with PPROM. Thus, vitamin C supplementation should be made mandatory along with iron and calcium to antenatal women to avoid the complications of PPROM.

Preparation and characterization of nanoliposomes entrapping medium-chain fatty acids and vitamin C by lyophilization

The complex nanoliposomes encapsulating both a hydrophilic drug vitamin C (vit C) and hydrophobic drug medium-chain fatty acids (MCFAs) was prepared by combining double emulsion method with dynamic high pressure microfluidization. The complex nanoliposomes was further freeze-dried under −86 °C for 48 h with sucrose at the sucrose/lipids ratio of 2:1(w/w) in order to enhance its stability. The freeze-dried complex nanoliposomes under the suitable conditions exhibited high entrapment efficiency of MCFAs (44.26 ± 3.34)%, relatively high entrapment efficiency of vit C (62.25 ± 3.43)%, low average size diameter (110.4 ± 7.28) nm and good storage stability at 4 °C for 60 days with slight changes in mean particle diameter and drug entrapment efficiencies. The results of transmission electron microscopy of freeze-dried complex nanoliposomes also showed that the freeze-dried samples with sucrose were stable without great increase in their particle sizes and without destroying their spherical shape. The results indicated that sucrose presented well protection effects in MCFAs-vit C complex nanoliposomes, suggesting the possibility of further usage in commercial liposomes.

The role of vitamin C in prevention of preterm premature rupture of membranes

BACKGROUND

Preterm premature rupture of membranes (PPROM) is one of the most important complications of the pregnancy and cause perinatal morbidity and mortality. History of PPROM is a risk factor of recurrent PPROM. Vitamin C plays an important role in collagen metabolism and increases resistance maintenance of the chorioamniotic membranes.

OBJECTIVES

The aim of this study is to evaluate the role of vitamin C supplementation in prevention of PPROM in women with a positive history of PPROM.

PATIENTS AND METHODS

This clinical trial study was performed on 170 pregnant women with the history of PPROM, with singleton pregnancy and gestational age 14 weeks in Imam-Reza Hospital, Mashhad University of Medical Sciences during 2008 to 2010. They were randomly divided into two groups. The case patients received 100 mg vitamin C daily from 14th weeks of gestation. PPROM occurrence was compared between two groups as an indicator of the protective effect of vitamin C supplements.

RESULTS

PPROM occurred in 44.7% of controls and 31.8% of cases (P &lt; 0.05). PROM occurred in 34.1% of controls and 18.8% of cases (P &lt; 0.05). Pregnancy was terminated at term gestation in 21.2% of controls and 49.4% of cases (P &lt; 0.05). Rupture of membranes was significantly decreased in the case group.

CONCLUSIONS

Vitamin C supplementations after 14th weeks of gestation can prevent from PPROM in women with the history of PPROM.

Bacterial vaginosis diagnosed at the first antenatal visit better predicts preterm labour than diagnosis later in pregnancy

This study was conducted as part of a double-blind randomised placebo-controlled trial, the aim of which was to determine whether vitamin C could reduce the recurrence risk of pre-term labour. In this study, women with a history of pre-term labour in a preceding pregnancy were randomised to receive either 250 mg vitamin C or a matching placebo twice daily until 34 weeks' gestation. They attended a dedicated pre-term labour clinic every 2 weeks. All women were screened for bacterial vaginosis (BV) at each visit. It was first determined that vitamin C did not have any effect on the presence of BV. Women who were diagnosed with BV before 20 weeks' gestation were at higher risk of delivering pre-term than those who developed BV after 20 weeks.

Invited commentary: disaggregating preterm birth to determine etiology

Identifying the causes of preterm birth has been problematic, in part because of heterogeneous pathways leading to the same event, early delivery. If a risk factor affects only a subset of cases, then studies that address the aggregate outcome will generate diluted measures of association. McElrath et al. (Am J Epidemiol. 2008;168(9):980-989) examined an array of potential influences on very early preterm birth (<28 weeks' gestation) and divided cases on the basis of proximal causes. Through factor analysis, they found empirical support for dividing preterm cases into 2 groups: intrauterine inflammation (preterm labor, preterm membrane rupture, placental abruption, and cervical insufficiency) and abnormal placentation (preeclampsia and intrauterine growth restriction). Replication of this classification in less extreme preterm births is needed, requiring large numbers of preterm births that have been characterized in detail. Nonetheless, this division is worthy of study by using previously collected data to determine whether, in fact, stronger associations are found for these subsets than for preterm birth in the aggregate. Ultimately, the test of the approach is in improving our understanding of etiology, ideally generating stronger, more consistent associations with preterm birth subsets than have been found for preterm birth in the aggregate.

Ehlers-Danlos-like dermal abnormalities in women with recurrent preterm premature rupture of fetal membranes

Preterm premature rupture of membranes (PPROM) likely results from weakening of the constituent connective tissue. It is uncertain if the alterations are limited to the fetal membranes or are also present in other sites such as the skin. The aim of the study was to compare the dermal structure of women suffering from recurrent PPROM with the dermis of both non-pregnant women and women with uneventful gestation. Skin biopsies were taken from 42 women who recently underwent PPROM, 33 women with uneventful gestation and 33 non-pregnant women. Histochemistry, immunohistochemistry, and electron microscopy were performed on these specimens and analyzed blindly. Morphologic changes were found in the dermis of most (33 of 42 at optical microscopy and 40 of 42 at ultrastructure) of the women suffering from PPROM. They were reminiscent of those found in some types of Ehlers-Danlos Syndrome (EDS). However, there was no clinical evidence suggesting a recognized form of EDS. We conclude that some cases of PPROM are a systemic connective tissue disorder representing a yet unidentified type of EDS.

Vitamins C and E in the latency period in women with preterm premature rupture of membranes

OBJECTIVE

To determine whether supplementation with vitamins C and E after preterm premature rupture of membranes (PPROM) is associated with an increased latency period.

METHODS

In this double-blind, randomized, controlled trial, 60 women with singleton pregnancies of 26 to 34 weeks' duration and PPROM were randomly assigned to vitamin C (500 mg/day) and vitamin E (400 IU/day) or placebo until delivery. All women received 2 doses of betamethasone in the first 24 h after admission as well as broad-spectrum antibiotic prophylaxis.

RESULTS

Important demographic, as well as clinical characteristics such as number of cases of chorioamnionitis, early neonatal sepsis, and respiratory distress syndrome, were similar in the 2 groups. A statically significant difference in the mean+/-S.D. number of days of latency was found between the groups (10.5+/-5.2 days vs. 3.5+/-4.0 days (P = 0.03).

CONCLUSION

Vitamins C and E supplementation of after PPROM is associated with a longer latency before delivery.

Vitamin C supplementation to prevent premature rupture of the chorioamniotic membranes: a randomized trial

BACKGROUND

Vitamin C is involved in the synthesis and degradation of collagen and is important for maintenance of the chorioamniotic membranes. Inadequate availability of ascorbic acid during pregnancy has been proposed as a risk factor for premature rupture of the chorioamniotic membranes (PROM).

OBJECTIVE

The objective of the study was to evaluate the effectiveness of 100 mg vitamin C/d in preventing PROM.

DESIGN

A controlled double-blind trial was performed. Pregnant women (n = 126) in their 20th wk of gestation were invited; 120 accepted and were randomly assigned to 2 groups (100 mg vitamin C/d or placebo). Every 4 wk, plasma and leukocyte vitamin C concentrations were measured, and each subject was evaluated for cervicovaginal infection. The incidence of PROM was recorded for each group as an indicator of the protective effect of vitamin C supplementation.

RESULTS

One hundred nine patients finished the study. Mean plasma vitamin C concentrations decreased significantly throughout the pregnancy in both groups (P = 0.001), and there were no significant differences between groups. Between weeks 20 and 36, mean leukocyte vitamin C concentrations decreased from 17.5 to 15.23 microg/10(8) cells in the placebo group and increased from 17.26 to 22.17 microg/10(8) cells in the supplemented group (within- and between-group differences: P = 0.001). The incidence of PROM was 14 per 57 pregnancies (24.5%) in the placebo group and 4 per 52 pregnancies (7.69%) in the supplemented group (relative risk: 0.26; 95% CI: 0.078, 0.837).

CONCLUSION

Daily supplementation with 100 mg vitamin C after 20 wk of gestation effectively lessens the incidence of PROM.

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.