Risk scoring systems for predicting preterm birth with the aim of reducing associated adverse outcomes

New prognostic criterion for the outcome of pregnancy in patients with threatening preterm birth

To identify new criteria for predicting the outcome of pregnancy in women with threatened preterm labor based on the establishment of the characteristics of differentiation and functional activity of memory T-cells in the population of CD8 + T-lymphocytes. The study involved 56 women with threatened preterm labor at 22-34 weeks of pregnancy. Depending on the outcome of pregnancy, patients were divided into 3 groups: Group I included 22 women by premature labor; group II - 34 women whose pregnancy ended by deliver at term. By tricolor flow cytofluorometry method the content of peripheral Tn, Tcm, Tem and Temra cells in CD8+ population was studied. Statistical analysis was carried out using programs «Statistica for Windows 13.0», «Microsoft Excel 2019» and «MedCalc 19.3». Patients with the threat of preterm birth were characterized by a significant increase in the relative content of CD8+ T-lymphocytes in the peripheral blood compared to the control group (p=0.001). When comparing this indicator in the subgroups of women with the threat of preterm birth, it was found that preterm birth was associated with significantly higher relative CD8 + lymphocyte counts (p=0.03) compared to the indicators of the subgroup of women who gave birth on time. When evaluating the results obtained, it was found that the percentage of CD8+Temra GranzymeB-producing cells in the group of patients with threatened preterm birth, whose pregnancy ended in preterm birth, was significantly lower than in the group of women who gave birth on time (p=0.003). The content of Tcm, Tem memory cells producing GranzymeB in the subgroups of women with pregnancy outcomes of timely and preterm birth did not have significant differences compared to the control group. Thus, the prediction of preterm birth is possible with a value of GranzymeB-producing CD8 + Tem equal to 8.2% or less (sensitivity-87.9%, specificity-85%, accuracy-87.9%). Thus, the identification of a new criterion will make it possible to predict preterm birth in a timely manner and promote the choice of optimal pregnancy management tactics, reasonable prevention of fetal respiratory distress syndrome and transfer of a woman to an obstetric hospital designed to provide high-tech care to premature newborns.

Antenatal non-medical risk assessment and care pathways to improve pregnancy outcomes: a cluster randomised controlled trial

Social deprivation negatively affects health outcomes but receives little attention in obstetric risk selection. We investigated whether a combination of (1) risk assessment focused on non-medical risk factors, lifestyle factors, and medical risk factors, with (2) subsequent institution of risk-specific care pathways, and (3) multidisciplinary consultation between care providers from the curative and the public health sector reduced adverse pregnancy outcomes among women in selected urban areas in the Netherlands. We conducted a cluster randomised controlled trial in 14 urban municipalities across the Netherlands. Prior to the randomisation, municipalities were ranked and paired according to their expected proportion of pregnant women at risk for adverse outcomes at birth. The primary outcome was delivery of a preterm and/or small for gestational age (SGA) baby, analysed with multilevel mixed-effects logistic regression analysis adjusting for clustering and individual baseline characteristics. A total of 33 community midwife practices and nine hospitals participated throughout the study. Data from 4302 participants was included in the Intention To Treat (ITT) analysis. The intervention had no demonstrable impact on the primary outcome: adjusted odds ratio (aOR) 1.17 (95% CI 0.84–1.63). Among the secondary outcomes, the intervention improved the detection of threatening preterm delivery and fetal growth restriction during pregnancy [aOR 1.27 (95% CI 1.01–1.61)]. Implementation of additional non-medical risk assessment and preventive strategies into general practices is feasible but did not decrease the incidence of preterm and/or SGA birth in the index pregnancy in deprived urban areas.

Trial registration Netherlands National Trial Register (NTR-3367).

Obstetric risk score - revalidated for triaging high-risk pregnancies in rural areas

BACKGROUND

A pregnancy risk score system in popular use in provincial and rural Queensland to assist with the triage decisions regarding the appropriate facility for pregnancy care has been upgraded with more recently recognised pregnancy risk factors.

AIMS

To review the usefulness of the revised pregnancy risk score system and the integrity of its continuing use.

MATERIALS AND METHODS

459 women attending regional/rural hospitals and 1963 women attending a major specialist hospital for their pregnancy care had a prospective risk score assessed, and the resulting score was examined in relationship to pregnancy outcomes.

RESULTS

There was a statistically significant positive relationship between a risk score of eight or more and an adverse outcome and a statistically significant negative relationship between a risk score of zero or one and adverse outcomes.

CONCLUSION

This study revalidates the risk score process for use in provincial and rural Queensland in delineating those women requiring care in a location with higher levels of clinical service capability. Women with a risk score of 8 or more have an increased likelihood of needing birth intervention and/or having an adverse neonatal outcome and should be recognised as needing the development of a multidisciplinary care plan and assessment in a facility that is appropriately resourced for their end of pregnancy care.

Clinical validation of a model predicting the risk of preterm delivery

OBJECTIVES

To validate a model predicting the risk of threatened preterm delivery and to establish the optimal threshold for this risk scoring system.

MATERIALS AND METHODS

Two cohorts were studied: one of singleton pregnancies without preterm premature rupture of membranes (PPROM) and no cervical cerclage (cohort 1) and one of twin pregnancies without PPROM and no cervical cerclage (cohort 2). Patients were included from January 1st 2013 until December 31st 2013 by the Regional Perinatal Network of Ile de France with patients transferred because of threatened preterm delivery at 22 to 32 weeks of gestation. The individual probability of delivery within 48 hours of admission was calculated using the nomogram for every patient. Discrimination and calibration of the nomogram as well as the optimal threshold were determined using R studio.

RESULTS

The nomogram accurately predicted obstetric outcome. Discrimination and calibration were excellent, with an area under the curve (AUC) of 0.88 (95% CI 0.86-0.90) for cohort 1 and 0.73 (95% CI 0.66-0.80) for cohort 2. The optimal threshold would be 15% for cohort 1 and 10% for cohort 2. Using these thresholds, the performance characteristics of the nomogram were: sensitivity 80% (cohort 1) and 69% (cohort 2), negative predictive value 94.8% (cohort 1) and 91.3% (cohort 2). Use of the nomogram would avoid 253 unnecessary transfers in cohort 1.

CONCLUSIONS

The nomogram was efficient and clinically relevant in our high risk population. A threshold set at 15% would help minimize the risk of preterm deliveries in singleton pregnancies and should reduce unnecessary, costly and stressful in utero transfer.

Screening for post 32-week preterm birth risk: how helpful is routine perinatal data collection?

Background

Preterm birth is a clinical event significant but difficult to predict. Biomarkers such as fetal fibronectin and cervical length are effective, but the often are used only for women with clinically suspected preterm risk. It is unknown whether routinely collected data can be used in early pregnancy to stratify preterm birth risk by identifying asymptomatic women. This paper tries to determine the value of the Victorian Perinatal Data Collection (VPDC) dataset in predicting preterm birth and screening for invasive tests.

Methods

De-identified VPDC report data from 2009 to 2013 were extracted for patients from Barwon Health in Victoria. Logistic regression models with elastic-net regularization were fitted to predict 37-week preterm, with the VPDC antenatal variables as predictors. The models were also extended with two additional variables not routinely noted in the VPDC: previous preterm birth and partner smoking status, testing the hypothesis that these two factors add prediction accuracy. Prediction performance was evaluated using a number of metrics, including Brier scores, Nagelkerke’s R², c statistic.

Results

Although the predictive model utilising VPDC data had a low overall prediction performance, it had a reasonable discrimination (c statistic 0.646 [95% CI: 0.596–0.697] for 37-week preterm) and good calibration (goodness-of-fit p = 0.61). On a decision threshold of 0.2, a Positive Predictive Value (PPV) of 0.333 and a negative predictive value (NPV) of 0.941 were achieved. Data on previous preterm and partner smoking did not significantly improve prediction.

Conclusions

For multiparous women, the routine data contains information comparable to some purposely-collected data for predicting preterm risk. But for nulliparous women, the routine data contains insufficient data related to antenatal complications.

Models of antenatal care to reduce and prevent preterm birth: a systematic review and meta-analysis

OBJECTIVE

To assess the effectiveness of models of antenatal care designed to prevent and reduce preterm birth (PTB) in pregnant women.

METHODS

We conducted a search of seven electronic databases and reference lists of retrieved studies to identify trials from inception up to July 2014 where pregnant women, regardless of risk factors for pregnancy complications, were randomly allocated to receive an alternative model of antenatal care or routine care. We pooled risks of PTB to determine the effect of alternative care models in all pregnant women. We also assessed secondary maternal and infant outcomes, women's satisfaction and economic outcomes.

RESULTS

15 trials involving 22,437 women were included. Pregnant women in alternative care models were less likely to experience PTB (risk ratio 0.84, 95% CI 0.74 to 0.96). The subgroup of women randomised to midwife-led continuity models of antenatal care were less likely to experience PTB (0.78, 0.66 to 0.91) but there was no significant difference between this group and women allocated to specialised care (0.92, 0.76 to 1.12) (interaction test for subgroup differences p=0.20). Overall low-risk women in alternative care models were less likely to have PTB (0.74, 0.59 to 0.93), but this effect was not significantly different from that in mixed-risk populations (0.91, 0.79 to 1.05) (subgroup p=0.13).

CONCLUSIONS

Alternative models of antenatal care for all pregnant women are effective in reducing PTB compared with routine care, but no firm conclusions could be drawn regarding the relative benefits of the two models. Future research should evaluate the impact of antenatal care models which include more recent interventions and predictive tests, and which also offer continuity of care by midwives throughout pregnancy.

PROSPERO REGISTRATION NUMBER

CRD42014007116.

Risk-scoring systems for predicting preterm birth with the aim of reducing associated adverse outcomes

BACKGROUND

Identification of pregnancies that are higher risk than average is important to allow the possibility of interventions aimed at preventing adverse outcomes like preterm birth. Many scoring systems designed to classify the risk of a number of poor pregnancy outcomes (e.g. perinatal mortality, low birthweight, and preterm birth) have been developed, but they have usually been introduced without evaluation of their utility and validity.

OBJECTIVES

To determine whether the use of a risk-screening tool designed to predict preterm birth (in combination with appropriate consequent interventions) reduces the incidence of preterm birth and very preterm birth, and associated adverse outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 June 2015).

SELECTION CRITERIA

All randomised or quasi-randomised (including cluster-randomised) or controlled clinical trials that compared the incidence of preterm birth between groups that used a risk-scoring instrument to predict preterm birth with those who used an alternative instrument, or no instrument; or that compared the use of the same instrument at different gestations. The reports may have been published in peer reviewed or non-peer reviewed publications, or not published, and written in any language.

DATA COLLECTION AND ANALYSIS

All review authors planned to independently assess for inclusion all the potential studies we identified as a result of the search strategy. However, we did not identify any eligible studies.

MAIN RESULTS

Searching revealed no trials of the use of risk-scoring systems for preventing preterm birth.

AUTHORS' CONCLUSIONS

The role of risk-scoring systems in the prevention of preterm birth is unknown.There is a need for prospective studies that evaluate the use of a risk-screening tool designed to predict preterm birth (in combination with appropriate consequent interventions) to prevent preterm birth, including qualitative and/or quantitative evaluation of their impact on women's well-being. If these prove promising, they should be followed by an adequately powered, well-designed randomised controlled trial.

Psychological, cultural and neuroendocrine profiles of risk for preterm birth

Background

Preterm birth remains a major obstetrical problem and identification of risk factors for preterm birth continues to be a priority in providing adequate care. Therefore, the purpose of this study was to elucidate risk profiles for preterm birth using psychological, cultural and neuroendocrine measures.

Methods

From a cross sectional study of 515 Mexican American pregnant women at 22–24 weeks gestation, a latent profile analysis of risk for preterm birth using structural equation modeling (SEM) was conducted. We determined accurate gestational age at delivery from the prenatal record and early ultrasounds. We also obtained demographic and prenatal data off of the chart, particularly for infections, obstetrical history, and medications. We measured depression (Beck Depression Inventory), mastery (Mastery scale), coping (The Brief Cope), and acculturation (Multidimensional Acculturation Scale) with reliable and valid instruments. We obtained maternal whole blood and separated it into plasma for radioimmunoassay of Corticotrophin Releasing Hormone (CRH). Delivery data was obtained from hospital medical records.

Results

Using a latent profile analysis, three psychological risk profiles were identified. The “low risk” profile had a 7.7 % preterm birth rate. The “moderate risk” profile had a 12 % preterm birth rate. The “highest risk” profile had a 15.85 % preterm birth rate. The highest risk profile had double the percentage of total infections compared to the low risk profile. High CRH levels were present in the moderate and highest risk profiles.

Conclusion

These risk profiles may provide a basis for screening for Mexican American women to predict risk of preterm birth, particularly after they are further validated in a prospective cohort study. Future research might include use of such an identified risk profile with targeted interventions tailored to the Hispanic culture.

A description of the methods of the Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be (nuMoM2b)

OBJECTIVE

The primary aim of the "Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be" is to determine maternal characteristics, which include genetic, physiologic response to pregnancy, and environmental factors that predict adverse pregnancy outcomes.

STUDY DESIGN

Nulliparous women in the first trimester of pregnancy were recruited into an observational cohort study. Participants were seen at 3 study visits during pregnancy and again at delivery. We collected data from in-clinic interviews, take-home surveys, clinical measurements, ultrasound studies, and chart abstractions. Maternal biospecimens (serum, plasma, urine, cervicovaginal fluid) at antepartum study visits and delivery specimens (placenta, umbilical cord, cord blood) were collected, processed, and stored. The primary outcome of the study was defined as pregnancy ending at <37+0 weeks' gestation. Key study hypotheses involve adverse pregnancy outcomes of spontaneous preterm birth, preeclampsia, and fetal growth restriction.

RESULTS

We recruited 10,037 women to the study. Basic characteristics of the cohort at screening are reported.

CONCLUSION

The "Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be" cohort study methods and procedures can help investigators when they plan future projects.

An instrument for broadened risk assessment in antenatal health care including non-medical issues

Introduction

Growing evidence on the risk contributing role of non-medical factors on pregnancy outcomes urged for a new approach in early antenatal risk selection. The evidence invites to more integration, in particular between the clinical working area and the public health domain. We developed a non-invasive, standardized instrument for comprehensive antenatal risk assessment. The current study presents the application-oriented development of a risk screening instrument for early antenatal detection of risk factors and tailored prevention in an integrated care setting.

Methods

A review of published instruments complemented with evidence from cohort studies. Selection and standardization of risk factors associated with small for gestational age, preterm birth, congenital anomalies and perinatal mortality. Risk factors were weighted to obtain a cumulative risk score. Responses were then connected to corresponding care pathways. A cumulative risk threshold was defined, which can be adapted to the population and the availability of preventive facilities. A score above the threshold implies multidisciplinary consultation between caregivers.

Results

The resulting digital score card consisted of 70 items, subdivided into four non-medical and two medical domains. Weighing of risk factors was based on existing evidence. Pilot-evidence from a cohort of 218 pregnancies in a multi-practice urban setting showed a cut-off of 16 points would imply 20% of all pregnant women to be assessed in a multidisciplinary setting. A total of 28 care pathways were defined.

Conclusion

The resulting score card is a universal risk screening instrument which incorporates recent evidence on non-medical risk factors for adverse pregnancy outcomes and enables systematic risk management in an integrated antenatal health care setting.

Comparison of Perinatal Outcome of Preterm Births Starting in Primary Care versus Secondary Care in Netherlands: A Retrospective Analysis of Nationwide Collected Data

Introduction. In Netherlands, the obstetric care system is divided into primary and secondary care by risk level of the pregnancy. We assessed the incidence of preterm birth according to level of care and the association between level of care at time of labor onset and delivery and adverse perinatal outcome. Methods. Singleton pregnancies recorded in Netherlands Perinatal Registry between 1999 and 2007, with spontaneous birth between 25(+0) and 36(+6) weeks, were included. Three groups were compared: (1) labor onset and delivery in primary care; (2) labor onset in primary care and delivery in secondary care; (3) labor onset and delivery in secondary care. Multivariable logistic regression analyses were performed to calculate the risk of perinatal mortality and Apgar score ≤4. Results. Of all preterm deliveries, 42% had labor onset and 7.9% had also delivery in primary care. Women with labor onset between 34(+0) and 36(+6) weeks who were referred before delivery to secondary care had the lowest risk of perinatal mortality (aOR 0.49 (0.30-0.79)). Risk of perinatal mortality (aOR 1.65; 95% CI 1.20-2.27) and low Apgar score (aOR 1.95; 95% CI 1.53-2.48) were significantly increased in preterm home delivery. Conclusion. Referral before delivery is associated with improved perinatal outcome in the occurrence of preterm labor onset in primary care.

The diagnostic value of cervicovaginal and serum ferritin levels in midgestation time to predict spontaneous preterm delivery

BACKGROUND

The aim of this study was to determine diagnostic value of cervicovaginal ferretin and serum ferretin levels at midgestation time in predicting preterm delivery in singleton pregnancies.

PATIENTS AND METHODS

A diagnostic test study through a prospective cohort design was carried out on 300 singleton pregnant women in 2012. A blood sample was obtained from all the patients within 22-24 gestational weeks for laboratory assessment of serum ferretin, and cervicovaginal sample was also taken to assess cervicovaginal ferritin level. Ferritin levels were compared between term and preterm deliveries at 37, 34 and 32 weeks of gestation. Receiver operating characteristics (ROC) curves were plotted to assess the diagnostic test values.

RESULTS

Mean serum ferritin level was 55.38 [standard deviation (SD 23.8)] ng/mL in term deliveries versus a mean of 91.27 (SD 25.2) ng/mL in preterm deliveries, which showed a statistically significant difference (P < 0.001). The ferritin levels in cervicovaginal term delivery group had mean of 11.29 (SD 16.2) ng/mL compared with a mean of 21.95 (SD 10.1) ng/mL among those with preterm delivery before 37 weeks of gestational age(P < 0.001). The cervicovaginal ferritin level had a moderate to good diagnostic value with an area under curve being above 0.8 for all assessments. The serum ferritin level had a moderate to good diagnostic value with an area under curve being above 0.8 for all assessments. In both tests, its diagnostic value was higher for predicting preterm delivery at earlier gestational age.

CONCLUSIONS

The results of this study indicate that high levels of serum and cervicovaginal ferritin in singleton pregnancies may alert the clinician of the risk of preterm delivery. Serum and cervicovaginal ferritin measurement at midgestation may be used as a predictive scale for preterm delivery in singleton pregnancies.

Antenatal interventions to reduce preterm birth: an overview of Cochrane Systematic Reviews

BACKGROUND

Several factors are associated with an increased risk of preterm birth (PTB); therefore, various interventions might have the potential to influence it. Due to the large number of interventions that address PTB, the objective of this overview is to summarise evidence from Cochrane reviews regarding the effects and safety of these different interventions.

METHODS

We conducted a systematic literature search in the Cochrane Database of Systematic Reviews. Included reviews should be based on randomised controlled trials comparing antenatal non-pharmacological and pharmacological interventions that directly or indirectly address PTB with placebo/no treatment or routine care in pregnant women at less than 37 completed weeks of gestation without signs of threatened preterm labour. We considered PTB at less than 37 completed weeks of gestation as the primary outcome.

RESULTS

We included 56 Cochrane systematic reviews. Three interventions increased PTB risk significantly. Twelve interventions led to a statistically significant lower incidence of PTBs. However, this reduction was mostly observed in defined at-risk subgroups of pregnant women. The remaining antenatal interventions failed to prove a significant effect on PTB < 37 weeks, but some of them at least showed a positive effect in secondary outcomes (e.g., reduction in early PTBs). As an unintended result of this review, we identified 28 additional Cochrane reviews which intended to report on PTB < 37 weeks, but were not able to find any RCTs reporting appropriate data.

CONCLUSIONS

The possible effects of a diverse range of interventions on PTB have been evaluated in Cochrane systematic reviews. Few interventions have been demonstrated to be effective and a small number have been found to be harmful. For around half of the interventions evaluated, the Cochrane review concluded that there was insufficient evidence to provide sound recommendations for clinical practice. No RCT evidence is available for a number of potentially relevant interventions.

Using an Optimality Index to Understand Perinatal Health Disparities: A Pilot Study With Latina Immigrants

PURPOSE

This study demonstrates preliminary evidence of the utility of an optimality index as a simple tool for monitoring complications across the perinatal period.

METHOD

The medical records of 147 Latina women participating in a preventive randomized controlled trial for perinatal depression were reviewed for outcomes across the perinatal period.

RESULTS

Application of the optimality index found optimality scores ranging from 77.3% to 97.7% in a Latina immigrant population known to have low rates of low-birthweight infants and preterm birth. Optimality scores were significantly lower among women who had a preterm birth or low-birthweight infant.

DISCUSSION

The ability of optimality indices to capture within-group variability will allow for a more nuanced understanding of the antecedents and sequelae of negative birth outcomes.

IMPLICATIONS FOR PRACTICE

Increasing reliance on electronic medical records will facilitate the calculation of optimality scores that can be used to track patterns of perinatal health disparities.