Immunologic aspects of preeclampsia

Preeclampsia is a syndrome with multiple etiologies. The diagnosis can be made without proteinuria in the presence of dysfunction of at least 1 organ associated with hypertension. The common pathophysiological pathway includes endothelial cell activation, intravascular inflammation, and syncytiotrophoblast stress. There is evidence to support, among others, immunologic causes of preeclampsia. Unlike defense immunology, reproductive immunology is not based on immunologic recognition systems of self/non-self and missing-self but on immunotolerance and maternal-fetal cellular interactions. The main mechanisms of immune escape from fetal to maternal immunity at the maternal-fetal interface are a reduction in the expression of major histocompatibility complex molecules by trophoblast cells, the presence of complement regulators, increased production of indoleamine 2,3-dioxygenase, activation of regulatory T cells, and an increase in immune checkpoints. These immune protections are more similar to the immune responses observed in tumor biology than in allograft biology. The role of immune and nonimmune decidual cells is critical for the regulation of trophoblast invasion and vascular remodeling of the uterine spiral arteries. Regulatory T cells have been found to play an important role in suppressing the effectiveness of other T cells and contributing to local immunotolerance. Decidual natural killer cells have a cytokine profile that is favored by the presence of HLA-G and HLA-E and contributes to vascular remodeling. Studies on the evolution of mammals show that HLA-E, HLA-G, and HLA-C1/C2, which are expressed by trophoblasts and their cognate receptors on decidual natural killer cells, are necessary for the development of a hemochorial placenta with vascular remodeling. The activation or inhibition of decidual natural killer cells depends on the different possible combinations between killer cell immunoglobulin-like receptors, expressed by uterine natural killer cells, and the HLA-C1/C2 antigens, expressed by trophoblasts. Polarization of decidual macrophages in phenotype 2 and decidualization of stromal cells are also essential for high-quality vascular remodeling. Knowledge of the various immunologic mechanisms required for adequate vascular remodeling and their dysfunction in case of preeclampsia opens new avenues of research to identify novel biological markers or therapeutic targets to predict or prevent the onset of preeclampsia.

Impact of prenatal corticosteroid therapy on sickle cell disease in pregnant women

OBJECTIVE

To evaluate safety of prenatal corticosteroids in pregnancies of women with sickle cell disease.

METHODS

A multicenter observational study of patients with sickle cell disease, comparing vaso-occlusive crises (VOC) requiring hospital care between pregnancies with versus without prenatal corticosteroids.

RESULTS

In 40 pregnancies exposed to prenatal corticosteroids, compared with 370 unexposed pregnancies, VOC were not more frequent (62.5% vs 57.9%, P = 0.578) but they were more severe, with more intensive care hospitalizations (25.0% vs 12.9%, P = 0.039), emergency transfusions (44.7% vs 22.7%, P = 0.006), and acute chest syndromes (22.5% vs 8.9%, P = 0.010). These differences persisted after adjustment for severity and type of sickle cell syndrome (for intensive care admission adjusted odds ratio [aOR] 2.73, 95% confidence interval [CI] 1.10-6.79, P = 0.031 and for acute chest syndrome aOR 4.15, 95% CI 1.57-14.4, P = 0.008). VOC occurred on average 1.2 days following steroid administration. When comparing 36 patients receiving corticosteroids for fetal maturation with 58 patients who were hospitalized for obstetrical complications before 34 weeks of pregnancy but that did not receive corticosteroids, VOC incidence was not significantly higher (41.7% vs 31.5%, P = 0.323).

CONCLUSION

The present study was the first to study the impact of prenatal corticosteroids on sickle cell disease. They were associated with more severe VOC, suggesting that steroids should be avoided in these women.

Neonatal outcomes for women at risk of preterm delivery given half dose versus full dose of antenatal betamethasone: a randomised, multicentre, double-blind, placebo-controlled, non-inferiority trial

BACKGROUND

Antenatal betamethasone is recommended before preterm delivery to accelerate fetal lung maturation. However, reports of growth and neurodevelopmental dose-related side-effects suggest that the current dose (12 mg plus 12 mg, 24 h apart) might be too high. We therefore investigated whether a half dose would be non-inferior to the current full dose for preventing respiratory distress syndrome.

METHODS

We designed a randomised, multicentre, double-blind, placebo-controlled, non-inferiority trial in 37 level 3 referral perinatal centres in France. Eligible participants were pregnant women aged 18 years or older with a singleton fetus at risk of preterm delivery and already treated with the first injection of antenatal betamethasone (11·4 mg) before 32 weeks' gestation. We used a computer-generated code producing permuted blocks of varying sizes to randomly assign (1:1) women to receive either a placebo (half-dose group) or a second 11·4 mg betamethasone injection (full-dose group) 24 h later. Randomisation was stratified by gestational age (before or after 28 weeks). Participants, clinicians, and study staff were masked to the treatment allocation. The primary outcome was the need for exogenous intratracheal surfactant within 48 h after birth. Non-inferiority would be shown if the higher limit of the 95% CI for the between-group difference between the half-dose and full-dose groups in the primary endpoint was less than 4 percentage points (corresponding to a maximum relative risk of 1·20). Four interim analyses monitoring the primary and the secondary safety outcomes were done during the study period, using a sequential data analysis method that provided futility and non-inferiority stopping rules and checked for type I and II errors. Interim analyses were done in the intention-to-treat population. This trial was registered with ClinicalTrials.gov, NCT02897076.

FINDINGS

Between Jan 2, 2017, and Oct 9, 2019, 3244 women were randomly assigned to the half-dose (n=1620 [49·9%]) or the full-dose group (n=1624 [50·1%]); 48 women withdrew consent, 30 fetuses were stillborn, 16 neonates were lost to follow-up, and 9 neonates died before evaluation, so that 3141 neonates remained for analysis. In the intention-to-treat analysis, the primary outcome occurred in 313 (20·0%) of 1567 neonates in the half-dose group and 276 (17·5%) of 1574 neonates in the full-dose group (risk difference 2·4%, 95% CI -0·3 to 5·2); thus non-inferiority was not shown. The per-protocol analysis also did not show non-inferiority (risk difference 2·2%, 95% CI -0·6 to 5·1). No between-group differences appeared in the rates of neonatal death, grade 3-4 intraventricular haemorrhage, stage ≥2 necrotising enterocolitis, severe retinopathy of prematurity, or bronchopulmonary dysplasia.

INTERPRETATION

Because non-inferiority of the half-dose compared with the full-dose regimen was not shown, our results do not support practice changes towards antenatal betamethasone dose reduction.

FUNDING

French Ministry of Health.

Mid-trimester miscarriage and subsequent pregnancy outcomes: the role of cervical insufficiency in a cohort of 175 cases

OBJECTIVE

To evaluate the causes of MTM and their impact on subsequent pregnancies.

MATERIAL AND METHODS

A retrospective single-center cohort study of all pregnancies with a second-trimester pregnancy loss between 14 weeks and 21 weeks + 6 days gestation, excluding terminations of pregnancy (TOP) and in utero fetal deaths. Predefined criteria were used to allocate cases to one of 6 primary etiologic diagnoses: cervical insufficiency, chorioamnionitis, placental anomalies, fetal anomalies, iatrogenic causes, or abdominal trauma.

RESULTS

Among 578 mid-trimester fetal losses, 175 were MTM, a prevalence of 5.7 per 1000 live births in the center. The suspected primary cause was cervical insufficiency in 76 cases (43.4%), chorioamnionitis in 59 (33.7%), placental anomalies or preterm premature rupture of membranes in 26 (14.8%), iatrogenic in 8 (4.6%), trauma in 3 (1.7%), and undetermined in 3 cases (1.7%). A subsequent pregnancy beyond 14 WG was recorded for 78 patients. Recurrent MTM occurred in 21.8% and preterm deliveries in 14.1% ; 13% of patients without evidence of cervical insufficiency in the index pregnancy required emergency cerclage.

CONCLUSION

Cervical insufficiency was the leading cause of MTM, with a high risk of recurrent MTM or preterm birth, thus prophylactic cerclage or cervical length measurements should be considered for subsequent pregnancies.

Staffing needs for unscheduled activity in obstetrics and gynecology

INTRODUCTION

To determine a minimum threshold of medical staffing needs (obstetricians-gynecologists, anesthesiologists-resuscitation specialists, nurse-anesthetists, pediatricians, and midwives) to ensure the safety and quality of care for unscheduled obstetrics-gynecology activity.

MATERIALS AND METHODS

Face to face meetings of French healthcare professionals involved in perinatal care in different types of practices (academic hospital, community hospital or private practice) who belong to French perinatal societies: French National College of Gynecologists-Obstetricians (CNGOF), the French Society of Anesthesia and Resuscitation Specialists (SFAR), the French Society of Neonatology (SFN), the French Society of Perinatal Medicine (SFMP), the National College of French Midwives (CNSF), and the French Federation of Perinatal Care Networks (FFRSP).

RESULTS

Different minimum thresholds for each category of care provider were proposed according to the number of births/year in the facility. These minimum thresholds can be modulated upwards as a function of the level of care (Level 1, 2 or 3 for perinatal centers), existence of an emergency department, and responsibilities as a referral center for maternal-fetal and/or surgical care. For example, an obstetrics-gynecology department handling 3000-4500 births per year without serving as a referral center must have an obstetrician-gynecologist, an anesthesiologist-resuscitation specialist, a nurse-anesthetist, and a pediatrician onsite specifically to provide care for unscheduled obstetrics-gynecology needs and a second obstetrician-gynecologist available within a time compatible with security requirements 24/7; the number of midwives always present (24/7) onsite and dedicated to unscheduled care is 5.1 for 3000 births and 7.2 for 4500 births. A maternity unit's occupancy rate must not exceed 85 %.

CONCLUSION

The minimum thresholds proposed here are intended to improve the safety and quality of care of women who require unscheduled care in obstetrics-gynecology or during the perinatal period.

[Fetal scalp pH during labor: Which threshold for intervention?]

OBJECTIVE

In case of abnormal fetal heart rate, there is no consensus on the decision threshold pH scalp leading to a rapid birth. The objective of this study was to compare neonatal issues and cesarean rate in two maternity using different decision thresholds of scalp pH.

MATERIAL AND METHODS

A comparative retrospective study conducted in two level III maternity units between January 2013 and May 2014, one maternity unit used a decision threshold of 7.20 (maternity unit 7,20), and the other one a threshold of 7.25 (maternity unit 7,25). An adverse neonatal outcome was defined by a composite endpoint of neonatal morbidity. The risk of cesarean was assessed using a multivariate analysis.

RESULTS

One hundred and four patients were included in the maternity unit 7,20 and 163 patients in the maternity 7,25. Adverse neonatal outcome was similar in both maternities (25% vs. 30,1%; P=0.4). The average pH at birth was similar in both maternities, as well as the Apgar score at 5minutes and neonatal transfer rates. However, BE<-12 was more frequent in maternity using 7,20 scalp pH threshold (7% vs. 0%; P<0.01). The cesarean rate was higher in maternity 7,25 (adjusted OR=2.23 95% CI [1.17-4.25]).

CONCLUSION

It seems that a decisional threshold fixed to 7,20 could be used reasonably. It could allow to reduce cesarean rate. Other studies are, however, needed to confirm that such threshold of 7,20 does not increase the risk of severe acidosis.