Medical and Surgical Interventions Available Before a Periviable Birth

Perinatal care for the extremely preterm infant

Being born preterm (prior to 37 weeks of completed gestation) is a leading cause of childhood death up to five years of age, and is responsible for the demise of around one million preterm infants each year. Rates of prematurity, which range from approximately 5 to 18% of births, are increasing in most countries. Babies born extremely preterm (less than 28 weeks' gestation) and in particular, in the periviable (20^0/7-25^6/7 weeks) period, are at the highest risk of death, or the development of long-term disabilities. The perinatal care of extremely preterm infants and their mothers raises a number of clinical, technical, and ethical challenges. Focusing on 'micropremmies', or those born in the periviable period, this paper provides an update regarding the aetiology and impacts of periviable preterm birth, advances in the antenatal, intrapartum, and acute post-natal management of these infants, and a review of counselling/support approaches for engaging with the infant's family. It concludes with an overview of emerging technology that may assist in improving outcomes for this at-risk population.

Controversies in treatment practices of the mother-infant dyad at the limit of viability

In the setting of threatened extreme preterm birth, balancing maternal and fetal risks and benefits in order to choose the best available treatment options is of utmost importance. Inconsistency in treatment practices for infants born between 22 and 24 weeks of gestatotional age may account for inter-hospital variation in survival rates with and without impairment. Most importantly, non-biased and accurate information must be presented to the family as soon as extremely preterm birth is suspected, including counseling on morbidities and mortality associated with delivery at the limits of viability. This review will focus on different therapeutic medical and surgical practices available for threatened extremely preterm birth to improve fetal and maternal outcomes while highlighting the importance of patient-centered approaches.

Periviable Premature Rupture of Membranes

Periviable deliveries (less than 26 weeks) are a small percentage of deliveries but account for a disproportionately high number of long-term morbidities. Few studies describe interventions and outcomes for periviable preterm premature rupture of membranes (PPROM). The available reports may include only those neonates who received resuscitation, making interpretation and application difficult. Counseling should consider the impact of oligohydramnios on fetal lung development. This article discusses standard and experimental interventions that may offer neonatal benefit. Antenatal corticosteroids, antibiotics, and magnesium sulfate may improve outcomes but data to support an improvement in outcome are limited. Studies specifically evaluating these interventions are needed.

Factors associated with preterm birth in women undergoing cervical cerclage

OBJECTIVES

Cervical cerclage is used to manage women at high risk of late miscarriage (LM) and spontaneous preterm birth (PTB) due to factors such as history of cervical insufficiency (CI), uterine anomaly, cervical surgery and ultrasound (US) diagnosed cervical shortening. Urinary tract infection (UTI) and subsequent pyelonephritis, and bacterial infection are associated with PTB, but their role in PTB after cervical cerclage is unknown. We examined the relationship between UTI and bacterial vaginosis (BV), fetal fibronectin (fFN) test and PTB in women undergoing elective- or US-indicated cervical cerclage. We also investigated whether fetal fibronectin (fFN) test were useful to predict PTB.

STUDY DESIGN

This is a single center, retrospective study of singleton pregnant women at PTB clinic, University College London Hospital (UCLH, 2005-2015) who underwent elective or US-indicated cervical cerclage. Women were tested for UTI and BV before cerclage placement and received mid-gestation fFN testing. Patient data were extracted from the PTB clinic database and electronic records. Statistical analyses used Pearson's chi-square and Mann-Whitney U tests. P values were corrected by Bonferroni method as required.

RESULTS

267 singleton pregnant women attended our clinic with completed birth outcome. Of those, 32.2% (86/267) delivered prematurely. All women with UTI or BV received antibiotic treatment. Women with a UTI before cerclage placement were more likely to deliver preterm when compared to those with negative MSU culture (OR 3.39, 95%CI 1.24-9.27, p = 0.04). Their gestational age at delivery were also lower than those with negative MSU result (36⁺⁶, IQR 31⁺⁴-38⁺²week vs 38⁺¹, IQR 36⁺¹-39⁺⁵-week, p = 0.05). However, UTI after cerclage placement or BV either before or after cerclage placement were not associated with PTB. Women who had a positive fFN result were more likely to deliver preterm (OR 3.85, 95% CI 1.81-8.41, p = 0.0007).

CONCLUSIONS

The presence of a UTI before cervical cerclage is associated with a higher rate of PTB in women who receive a cervical cerclage, even when treated. We did not find an association between pre or post-cerclage BV or post-cerclage UTI and PTB. Further research is needed to elucidate the link between UTI and PTB in women undergoing cervical cerclage.

Deliveries at extreme prematurity: outcomes, approaches, institutional variation, and uncertainty

PURPOSE OF REVIEW

Medical decision making and practices surrounding extremely premature birth remains challenging for parents and care providers alike. Recently, concerns have been raised regarding wide practice variation, selection bias, and the limitations of outcomes data in this population. The purpose of this review is to summarize the recent literature relevant to deliveries at extreme prematurity with a focus on outcomes, approaches, and institutional variation.

RECENT FINDINGS

Newer data suggest that evidence-based clinical guidelines and protocols for both pregnant women and infants at extreme prematurity are emerging and may improve care and outcomes at lower gestational ages. It has also been recently shown that wide practice variation, selection bias, and methodological limitations of outcomes data reporting with respect to deliveries at extreme prematurity exist.

SUMMARY

Counseling at extreme prematurity should prioritize eliciting parental values and preferences with the goal of personalized shared decision-making. Providers should recognize limitations in counseling families at extreme prematurity, including selection bias, institutional variation, outcomes inaccuracies, prognostic uncertainty, and implicit biases. Standardized reporting of perinatal outcomes should be developed to help alleviate current outcomes misrepresentations and improve counseling at extreme prematurity. Education for providers in advanced communication skills is needed when counseling at extreme prematurity.