Introduction: The risks of pregnancy in women of advanced maternal age are not consensual amongst studies. The aim of this metaanalysis  was to determine whether women of advanced maternal age (≥ 35 years old) had worse obstetrical and perinatal outcomes than non- advanced maternal age women (20 - 34 years old) in singleton, naturally-conceived pregnancies.Material and Methods: We searched PubMed/ MEDLINE, IndexRMP and the Cochrane Database of Systematic Reviews. Ten studies were included according to the following criteria: population of > 1000 nulliparous and/or multiparous women with singleton gestations who did not undergo any type of infertility treatment. Using Review Manager v. 5.3, two meta-analysis were performed: one comparing the outcomes of 20 - 34-year-old vs 35 - 40-year-old women, and another comparing the outcomes of 35 - 40-year-old women vs > 40-year-old women.Results: Women aged 35 - 40 years old were more likely to have > 12 years of education than 20 - 34 years old and > 40 years old women. Advanced maternal age women (35 - 40 and > 40 years old) were more likely to be overweight and having gestational diabetes and gestational hypertension. They were also more likely to undergo induced labour and elective caesarean deliveries. Furthermore, they had worse perinatal outcomes such as preterm delivery, low birthweight babies, higher rates of Neonatal Intensive Care Unit admission and worse Apgar scores. Advanced maternal age women had higher rates of perinatal mortality and stillbirth.Discussion: Most authors present similar results to our study. Although the majority of adverse outcomes can be explained through the physio-pathological changes regarding the female reproductive apparatus that come with aging and its inherent comorbidities, according to the existing literature advanced maternal age can be an independent risk factor per se. In older pregnant women without comorbidities such as gestational hypertension or diabetes there are still worse obstetric and perinatal outcomes, which indicate that advanced maternal age is an independent strong risk factor alone.Conclusion: Advanced maternal age women are at a higher risk of adverse obstetrical and perinatal outcomes. In both comparisons, worse outcomes were more prevalent in the older group, suggesting that poorer outcomes are more prevalent with increasing age.

Pre-term delivery is the leading cause of neonatal morbidity, mortality and long-term sequels. This is an open label randomised controlled trial with women with confirmed threatened pre-term labour (TPTL) after efficient tocolytic therapy with atosiban. The main outcome measure of this study was the latency period until delivery and secondary outcomes were the number of recurrent episodes of TPTL and fetal and maternal morbidity. Patients were assigned to treatment or control groups using a computer generated randomisation table. The treatment group received 200 mg vaginal progesterone daily until delivery and the control group received no therapy or placebo. The study cohort comprised 52 pregnant women, 26 in each arm, showing similar characteristics; the treatment group had a longer latency period until delivery and this was statistically significant (55 vs 38 days, p = 0.024). This study points to the benefits of the vaginal administration of progesterone, especially in prolonging latency period until delivery.

Objective To provide evidence of the existence of membrane progesterone receptor alpha (mPRa) on regulatory T cells (Treg) in peripheral blood during pregnancy, postulating a possible explanation for the effect of progesterone on preterm birth.Design Cross-sectional study.Setting Tertiary Obstetric Department in a University Hospital.Population Healthy pregnant women.Methods Treg cells from peripheral blood samples were studied by flow cytometry using multiple monoclonal antibody expression. Conclusions This research shows that Treg cells express mPRa during pregnancy, which might play an important role in immune modulation by progesterone.

Progesterone acts as an immunosteroid by contributing to the establishment of a pregnancy-protective milieu. It seems that it is the responsibility of progesterone to evade the inflammatory events that lead to parturition. T regulatory lymphocytes (Treg cells) could further explain the inhibition of the inflammatory mechanisms that lead to labour through the rapid action of progesterone on this cell subset. We investigated Treg cells and the membrane progesterone receptor α (mPRα) in these immune cells with in relationship to human parturition. This pilot cohort study was conducted in a single-centre tertiary obstetrical unit with 20 normal pregnant women. Variation in the absolute and relative frequency of CD4(+) T cells, Treg cells, and of mPR(α+) Treg cells was calculated by flow cytometry on three occasions (second and third trimesters; delivery day). Our results show that during normal pregnancy there is a generalised increase in Treg cells and mPR(α+) Treg cells, from the second to the third trimesters (23.4% vs. 52.3% and 4.3% vs. 8.3%, respectively). On the contrary, on delivery day, compared with the values in the third trimester, there is a sudden decrease in both Treg cells (52.3% vs. 17.4%) and mPR(α+) Treg cells (8.3% vs. 6.1%). Our findings suggest that human labour may develop as a consequence of a decline in mPR(α+) Treg cells, which reduces progesterone anti-inflammatory action through Treg cells.

This series results are in agreement with those in other studies. Even though pregnancy does not seem to adversely affect short-term renal allograft function, risks of obstetric and perinatal complications seem to be increased. Further studies of long term graft function and pediatric follow-up are needed.