Perspectives in the prevention of premature birth

Circulating Extracellular Vesicles microRNAs Are Altered in Women Undergoing Preterm Birth

Preterm labor (PTL) and preterm premature rupture of membranes (PPROM) lead to high perinatal morbidity/mortality rates worldwide. Small extracellular vesicles (sEV) act in cell communication and contain microRNAs that may contribute to the pathogenesis of these complications. We aimed to compare the expression, in sEV from peripheral blood, of miRNAs between term and preterm pregnancies. This cross-sectional study included women who underwent PTL, PPROM, and term pregnancies, examined at the Botucatu Medical School Hospital, SP, Brazil. sEV were isolated from plasma. Western blot used to detect exosomal protein CD63 and nanoparticle tracking analysis were performed. The expression of 800 miRNAs was assessed by the nCounter Humanv3 miRNA Assay (NanoString). The miRNA expression and relative risk were determined. Samples from 31 women—15 preterm and 16 term—were included. miR-612 expression was increased in the preterm groups. miR-612 has been shown to increase apoptosis in tumor cells and to regulate the nuclear factor κB inflammatory pathway, processes involved in PTL/PPROM pathogenesis. miR-1253, miR-1283, miR378e, and miR-579-3p, all associated with cellular senescence, were downregulated in PPROM compared with term pregnancies. We conclude that miRNAs from circulating sEV are differentially expressed between term and preterm pregnancies and modulate genes in pathways that are relevant to PTL/PPROM pathogenesis.

[Risk factors associated with spontaneous preterm deliveries before 30 weeks in Martinique F.W.I.: a case-control study]

OBJECTIVES

Early premature delivery is more prevalent in overseas territories than in continental France. Many differences are observed between pregnant women in France and in Martinique which may explain the higher preterm birth rate in the latter territory. The study compares prevalence of possible risk factors in preterm and term deliveries in Martinique.

PATIENTS AND METHODS

A retrospective study was conducted during two years (2010-2011). All deliveries before 30 weeks were included and several characteristics were compared with a group of term deliveries during the same period. All premature deliveries before 30 weeks were collected but only spontaneous ones were analysed.

RESULTS

Fifty deliveries before 30 weeks were recorded, among which 38 were spontaneous. Only a significantly higher prevalence of previous preterm delivery (OR=4.1 [1.3-13]) and twin pregnancies (OR=26.6 [3.19-219.6]) was found in the study group. Gram negative bacterial species were also more prevalent in vaginal sampling of preterm deliveries (OR=23.3 [2.7-204.6]).

CONCLUSION

Factors linked to prematurity before 30 weeks in Martinique are classical. Several features are different between pregnant women in France and in Martinique but do not appear as risk factors for prematurity in the latter territory.

Progestogens for treatment and prevention of pregnancy disorders

Progesterone appears to be the dominant hormone not only establishing a proper secretory endometrial development but also adequate decidualization to establish pregnancy and sustain pregnancy development. Progesterone is the natural immunoregulator to control the maternal immune system and not to reject the allogeneic fetus. There are two sources of progesterone: corpus luteum first and placenta later. Three progestogens can be used in pregnancy: (i) progesterone (per os, intravaginal and intramuscular), (ii) dydrogesterone (per os), and (iii) 17α-hydroxyprogesterone caproate (intramuscular). There are three indications, for which these progestogens can be clinically used either for treatment or prevention: (i) first trimester threatened and recurrent (habitual) abortion, (ii) premature labor/premature birth, and (iii) pre-eclampsia (hypertension in pregnancy). The available data are limited and only partially randomized. In threatened abortion the use of progesterone, dydrogesterone and 17α-hydroxyprogesterone caproate leads to a significant improved outcome, when at the time of threatened abortion a viable fetus has been ascertained by ultrasound. For prevention of recurrent abortion there are also some data indicating a significant effect compared with women without progestogen treatment. Prevention of preterm birth by progestogens (progesterone vaginally, orally and 17α-hydroxyprogesterone caproate intramuscularly) was significantly effective. The main study groups include pregnant women with a previous history of premature birth. However, also in women with shortened cervix use of progesterone seems to be helpful. The studies done so far in women with risk factors for pre-eclampsia or established pre-eclampsia were based on parenteral progesterone application. However, new studies are urgently needed.

[Risk factors for pre-term birth in Londrina, Paraná State, Brazil]

The objective of this study was to identify risk factors associated with pre-term birth among live births in a hospital in Londrina, Paraná State, Brazil. Cases consisted of 328 pre-term births, and controls were 369 births with gestational age greater than 37 weeks. A multiple hierarchical logistic regression analysis was carried out. There was a significant correlation (p < 0.05) between pre-term birth and the following variables: socioeconomic status (slum residence); low age of head-of-family; maternal BMI < 19 or > 30 kg/m2; history of prematurity; history of assisted reproduction; mothers in a relationship for less than two years; maternal stress; weekly maternal alcohol consumption; insufficient prenatal care; gestational complications such as bleeding, genital tract infection, altered amniotic fluid volume, high blood pressure, and hospital admission; and twin pregnancy. Regular walks during pregnancy were a protective factor. Improved quality of prenatal care and the identification of the above factors during pregnancy may help reduce premature birth.

Effects of oral l-arginine on the pulsatility indices of umbilical artery and middle cerebral artery in preterm labor

OBJECTIVE

The objective of the study was the estimation of the influence of oral supplementation with low-dose l-arginine on feto-placental circulation in women with threatened preterm labor.

STUDY DESIGN

Oral administration of 3g of L-arginine daily or placebo as a supplement to standard tocolytic therapy was tried in 70 women with threatened preterm delivery, randomly assigned to the L-arginine (n=37) or placebo (n=33) groups. Twenty-five and 20 completed the study, respectively. Doppler velocimetry of pulsatility indices (PI) of the umbilical (UA) and middle cerebral (MCA) arteries as well as pregnancy outcome and biochemical markers of nitric oxide synthesis (plasma amino acid and nitrite/nitrate levels, as well as 24 h nitrite/nitrate excretion with urine) were estimated.

RESULTS

Starting from the second week of therapy, the UA PI values were significantly lower in the L-arginine group than in the placebo group. Moreover, treatment with L-arginine caused a significant increase in MCA PI and cerebro-placental ratio (CPR) values. The changes in feto-placental circulation in the L-arginine group were not associated with any signs of increased nitric oxide synthesis.

CONCLUSION

Oral supplementation with low doses of L-arginine changed feto-placental blood flow distribution in patients with threatened preterm labor. The exact mechanism of L-arginine action on feto-placental circulation requires further investigation.

Physical abuse during pregnancy and preterm delivery

OBJECTIVE

This study was undertaken to assess the relationship between physical abuse during pregnancy and preterm delivery.

STUDY DESIGN

We conducted a hospital-based survey on physical abuse during pregnancy, which included 2660 women with consecutive live births. Women were interviewed and violence was assessed using the Abuse Assessment Screen. Data on sociodemographic, behavioral, and obstetric variables were also obtained. Mothers of preterm (<37 weeks; n = 217) were contrasted with mothers of term newborn infants (n = 2428). Logistic regression analysis was performed to estimate adjusted odds ratios.

RESULTS

Twenty-four percent of mothers of preterm newborn infants had experienced physical abuse during pregnancy compared with 8% of mothers of term newborn infants (P < .0001). Violence was associated with preterm birth even after controlling for age, marital status, education, income, parity, planned pregnancy, antenatal care, smoking, alcohol, and illicit drugs use (odds ratio = 3.14, 95% confidence interval, 2.00-4.93).

CONCLUSION

Women who have had physical abuse during pregnancy present a large increase in the risk of preterm delivery, independently from a large set of sociodemographic and behavioral characteristics usually recognized as determinants of preterm birth.

No effect of tocolytic therapy with atosiban on maternal serum interleukin-6 and tumor necrosis factor-alpha in threatened preterm labor

OBJECTIVES

We aimed to evaluate the effect of intravenous administration of tocolytic therapy with an oxytocin antagonist drug (atosiban) on maternal serum interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) levels in women with threatened preterm labor.

METHODS

The study population consisted of 46 women with a singleton pregnancy admitted to our department with a diagnosis of threatened preterm labor at between 26 and 34 weeks of gestation. Atosiban was administered to all women. Nine women (group A) progressed to delivery within 48 hours of admission. The remaining 37 women were divided in two groups: group B consisted of 16 women who remained undelivered at 48 hours but experienced delivery within 7 days and group C consisted of 21 women who did not deliver within the next 7 days. Maternal serum IL-6 and TNF-alpha levels were assessed in duplicate by a high sensitivity ELISA kit on patient admission and again at the end of treatment with atosiban (36 hours post-admission).

RESULTS

Serum IL-6 and TNF-alpha concentrations on admission were significantly higher in group A compared to those found in group B (p = 0.01) and group C (p = 0.04). Comparisons of serum IL-6 values on admission and at 36 hours after the initiation of atosiban treatment were comparable in group A (p = 0.95), group B (p = 0.39), and group C (p = 0.79). Similarly serum TNF-alpha levels on admission were not significantly different compared to those at the end of treatment in all groups (p = 0.85 for group A, p = 0.45 for group B, and p = 0.21 for group C).

CONCLUSIONS

No effect of tocolytic therapy with atosiban was observed on serum IL-6 and TNF-alpha levels in women with threatened preterm labor.

Does relaxation education in anxious primigravid Iranian women influence adverse pregnancy outcomes?: a randomized controlled trial

Maternal anxiety and stress are found to be predictors of adverse pregnancy outcomes, including low birth weight and prematurity.

OBJECTIVE

The aim of the study was to determine whether relaxation education in anxious pregnant Iranian women in their first pregnancy affects selected pregnancy outcomes, including birth weight, preterm birth, and surgical delivery rate.

SUBJECTS

A total of 110 obstetrically and medically low-risk primigravid women in Iran with a high anxiety level demonstrated by Spielberger's State-Trait Anxiety Inventory were randomly assigned into experimental and control groups.

METHOD

In this randomized controlled trial, the experimental group received routine prenatal care along with 7-week applied relaxation training sessions, while the control group received only routine prenatal care. Anxiety and perceived stress were measured by pre-educational and post-educational intervention. Data related to pregnancy outcomes include birth weight, gestational age at birth, and type of delivery.

RESULTS

Significant reductions in low birth weight, cesarean section, and/or instrumental extraction were found in the experimental group compared with the control group. No significant differences were found in the rate of preterm birth.

CONCLUSION

The findings suggest beneficial effects of nurse-led relaxation education sessions during the prenatal period. This intervention could serve as a resource for improving pregnancy outcomes in women with high anxiety.