Population attributable fractions for risk factors for spontaneous preterm births in 81 low- and middle-income countries: A systematic analysis

Pre-pregnancy intrauterine device use is associated with a reduced risk of subsequent preterm birth: a large population-based cohort study

BACKGROUND

The effect of pre-pregnancy intrauterine device (IUD) use on subsequent preterm birth (PTB) remains unclear. We aim to investigate the association between IUD use before pregnancy and subsequent PTB.

METHODS

A total of 240,437 women who participated in the National Free Preconception Health Examination Project (NFPHEP) in Yunnan from 2013 to 2019 were included in the study. All study participants were classified into three groups according to their use of pre-pregnancy contraceptive methods: non-method users, IUD users, and other method users. We used a multivariable Poisson regression model to investigate the association between the use of an IUD before pregnancy and subsequent PTB. Further models analyzed the multiplicative and additive interactions between pre-pregnancy IUD use and county deprivation.

RESULTS

Of all the participants, 45,374 (18.9%) used IUDs before pregnancy, 39,414 (16.4%) used other contraceptive methods, and 155,649 (64.7%) were non-method users. The overall PTB rate was 5.30% (95% confidence interval [95% CI], 5.20-5.38%), and women in the IUD group had a significantly lower PTB rate (4.86%, 95% CI 4.66-5.06%) than women in the non-method (5.42%, 95% CI 5.31-5.53%) and other method groups (5.33%, 95% CI 5.11-5.56%). IUD use before pregnancy was associated with a reduced risk of subsequent PTB (model 1: adjusted relative risk [aRR] 0.84, 95% CI 0.80 to 0.89; model 2: aRR 0.84, 95% CI 0.79 to 0.90). In counties with a normal level of development, IUD users had a 30% lower risk of subsequent PTB than non-users (aRR 0.70, 95% CI 0.63 to 0.78). Compared with non-IUD users (incuding non-method and other method users) from the least developed counties, those from counties with a normal level of socioeconomic development had the lowest risk of subsequent PTB (aRR 0.71, 0.62 to 0.82). The additive interaction between pre-pregnancy IUD use and low level of county development was statistically significant (relative excess risk due to interaction [RERI] -0.27, -0.41 to -0.14).

CONCLUSION

Pre-pregnancy IUD use is associated with a reduced risk of subsequent PTB. Pre-pregnancy IUD users in counties with a normal level of development were associated with a lower risk of subsequent PTB than their counterparts in the least developed countries.

TVS-guided cervical strain elastography is more effective than measuring cervical length as an independent predictor of spontaneous preterm delivery in asymptomatic, high-risk women during the mid-trimester

INTRODUCTION

TVS (Transvaginal Sonography) guided Cervical strain elastography (CSE) is now available in tertiary referral centers of LMICs (Low- and Middle-Income Countries). TVS cervical length (CL) assessment is being used routinely. Still, elastography is not used in clinical settings, although enough evidence suggests good predictive value towards sPTD (spontaneous Preterm Delivery). The clinical utility of elastography has not been tested among high-risk populations of LMICs for the prediction of sPTD.

AIM

To test the performance of TVS-CSE in predicting sPTD among asymptomatic women in the mid-trimester at risk of sPTD either due to clinical factors or due to a short cervix.

METHOD

Prospective observational study performed at a tertiary hospital in South India. Asymptomatic pregnant women between 16 and 24 weeks who had one or more clinical risk factors for sPTD or CL <2.5 cm were included. GE Voluson E-8 ultrasound machine was used. After CL measurement, elastography color coding was noted around the internal-os in the sagittal view. The strain ratio (SR) was calculated using the trace method on three ROIs (Region of Interest): Internal-os in sagittal view (IN), whole cervix in sagittal view (WN), and internal-os in axial view (AN). Reference Tissue (RT) of similar size and depth was chosen in the darkest blue region on elastography (stiffest area) outside the cervix, posterior/lateral to the cervix over the ligament insertion. Lower the SR - softer the cervix. Two trained fetal medicine consultants performed the initial 57 cases until intra/inter-observer correlation was satisfactory. Delivery before 37 weeks (after 26 weeks), in which the process of labor has begun spontaneously, or labor was induced after PPROM-was considered as sPTD. SRs were assessed to determine how well they could predict sPTD independently or combined with cervical length.

RESULTS

Out of 221 recruited,17 were lost to follow-up after 32 weeks; 204 were delivered in our hospital. Irrespective of the route of delivery, 71 (34.8%) had sPTD. Of the remaining 133, 106 delivered at term, and 27 underwent medically indicated PTD. Apart from multiple pregnancies, no other preterm-related risk factors (including CL < 2.5 cm) showed significant association with sPTD. Red CSE pattern around internal-os was associated with a significantly higher (54.5%) incidence of sPTD. CLs were similar (3.63 ± 0.67 vs. 3.63 ± 0.80, p = .981) whereas SRs in all three ROIs were significantly lower among sPTD group versus no sPTD group (IN:0.65 ± 0.29 vs 0.79 ± 0.30 p = .001, WN:0.34 ± 0.13 vs 0.39 ± 0.15, p = .013, AN:0.37 ± 0.16 vs 0.48 ± 0.26, p = .002, respectively). Using ROC curves, while CL was not predictive (AUROC 0.49, p = .81), SRs showed moderate predictive value toward sPTD with the best AUC of 0.624 (p = .003) at IN. Prediction was slightly better for early sPTD <32 weeks (AUC 0.653 p = 0.03). The best cutoff for SR at IN was 0.72, below which there was a moderate accuracy in predicting sPTD (sensitivity 52.11%, specificity 60.9%, PPV 41.57%, NPV 70.44%, diagnostic OR 1.69 and overall accuracy of 57.84%). A weak positive correlation is seen between IN and CL (Pearson's correlation R = 0.181). Multi-variable binary logistic regression analysis suggested that SRs at IN (Adjusted OR - 0.259 CI 0.079-0.850), AN (Adjusted OR 0.182 CI 0.034-0.963), Multiple Pregnancy (Adjusted OR 3.5 CI 1.51-8.13) and previous sPTD/PPROM (Adjusted OR 2.72 CI 0.97-7.61) independently predicted sPTD.

CONCLUSIONS

TVS CSE performed better than CL as an independent predictive tool toward sPTD, although predictive efficacy was modest at best. Since technology is now available in high-end USG machines in tertiary care centers, we propose optimal utilization of CSE in LMICs to triage at-risk populations since low SRs are strongly associated with sPTD.

The costs and benefits of scaling up interventions to prevent poor birth outcomes in low-income and middle-income countries: a modelling study

BACKGROUND

We estimated the benefits and costs of a set of preventive interventions that could be delivered during antenatal care to prevent poor birth outcomes, including small-for-gestational-age and preterm births. We built on the assumptions and analyses underlying the Lancet Series on small vulnerable newborns (SVNs) and extended that work by incorporating more recent data, focusing only on the subset of preventive interventions, and examining a broader range of effects. A primary aim of the study was to provide a framework that decision makers could use to design programmes for women and children.

METHODS

The analyses used the Lives Saved Tool (LiST) to estimate the effects and costs of scaling up the 11 preventive interventions identified in the SVN Series to improve birth outcomes. We used LiST estimates of effects and costs to estimate benefit-cost ratios (BCRs) for two intervention packages (one with interventions proven to improve birth outcomes and one with proven interventions plus interventions with potential to improve birth outcomes) and for the individual interventions in these packages for 80 low-income and middle-income countries (LMICs).

FINDINGS

Both packages of interventions had BCRs more than 1, with a proven package BCR of 7·3 (IQR 5·3-9·1) and a proven plus potential package BCR of 5·8 (4·4-6·9). We found that in all cases the individual interventions had BCRs more than 1, there was a wide range of BCR values for the different interventions, and the BCR varied depending on package and country.

INTERPRETATION

The analyses presented in this Article provide evidence that there are preventive interventions that, if scaled up in LMICs, could have a large effect on child health and provide benefits that greatly exceed the costs.

FUNDING

Global Affairs Canada.

Maternal inflammatory and microbial drivers of low birthweight in low- and middle-income countries

BACKGROUND

Low birthweight (LBW) is when an infant is born too soon or too small, and it affects one in seven infants in low- and middle-income countries. LBW has a significant impact on short-term morbidity and mortality, and it impairs long-term health and human capital. Antenatal microbial and inflammatory exposure may contribute to LBW.

METHODS

Ovid-Medline, Embase and Cochrane databases were searched for English-language articles evaluating inflammatory, microbial or infective causes of LBW, small-for-gestational age, intra-uterine growth restriction or prematurity. Inclusion criteria were human studies including published data; conference abstracts and grey literature were excluded. A narrative synthesis of the literature was conducted.

RESULTS

Local infections may drive the underlying causes of LBW: for example, vaginitis and placental infection are associated with a greater risk of prematurity. Distal infection and inflammatory pathways are also associated with LBW, with an association between periodontitis and preterm delivery and environmental enteric dysfunction and reduced intra-uterine growth. Systemic maternal infections such as malaria and HIV are associated with LBW, even when infants are exposed to HIV but not infected. This latter association may be driven by chronic inflammation, co-infections and socio-economic confounders. Antimicrobial prophylaxis against other bacteria in pregnancy has shown minimal impact in most trials, though positive effects on birthweight have been found in some settings with a high infectious disease burden.

CONCLUSION

Maternal inflammatory and infective processes underlie LBW, and provide treatable pathways for interventions. However, an improved understanding of the mechanisms and pathways underlying LBW is needed, given the impact of LBW on life-course.

The cost of inaction on preconception health in Nigeria: An economic impact analysis

A growing body of evidence has shown the effects of poor preconception health on adverse pregnancy outcomes and, subsequently, maternal and child morbidity and mortality. However, the cost of poor preconception health remains relatively unexplored. Using the case of Nigeria, this study provides the first estimate of the disease and economic burden of poor preconception health at a country level. Using data from international databases and the scientific literature, the study used a cost-of-illness approach to quantify the foregone productivity and direct healthcare costs resulting from six preconception risk factors (adolescent pregnancy, short birth interval, overweight and obesity, intimate partner violence, female genital mutilation, folate deficiency). The results indicate that 6.7% of maternal deaths, 10.9% of perinatal deaths, and 10.5% of late neonatal deaths were attributable to the selected preconception risk factors in 2020. The economic burden of poor preconception health in Nigeria was estimated at US$ 3.3 billion in 2020, of which over 90% was generated by premature mortality. If prevalence rates remain constant, total economic losses could amount to US$ 46.2 billion by 2035. This analysis paves the way for further studies investigating the economic costs and benefits of preconception interventions and policies in low and middle-income countries.

Supplementation with fortified balanced energy-protein during pregnancy and lactation and its effects on birth outcomes and infant growth in southern Nepal: protocol of a 2×2 factorial randomised trial

INTRODUCTION

Many women in low and middle-income countries enter pregnancy with low nutritional reserves with increased risk of fetal growth restriction and poor birth outcomes, including small-for-gestational-age (SGA) and preterm birth. Balanced energy-protein (BEP) supplements have shown reductions in risk of stillbirth and SGA, yet variations in intervention format and composition and limited evidence on the impact of BEP during lactation on growth outcomes warrant further study. This paper describes the protocol of the Maternal Infant Nutrition Trial (MINT) Study, which aims to evaluate the impact of a fortified BEP supplement during pregnancy and lactation on birth outcomes and infant growth in rural Nepal.

METHODS AND ANALYSIS

MINT is a 2×2 factorial, household randomised, unblinded, efficacy trial conducted in a subarea of Sarlahi District, Nepal. The study area covers six rural municipalities with about 27 000 households and a population of approximately 100 000. Married women (15-30 years) who become pregnant are eligible for participation in the trial and are randomly assigned at enrolment to supplementation with fortified BEP or not and at birth to fortified BEP supplementation or not until 6 months post partum. The primary pregnancy outcome is incidence of SGA, using the INTERGROWTH-21st standard, among live born infants with birth weight measured within 72 hours of delivery. The primary infant growth outcome is mean length-for-age z-score at 6 months using the WHO international growth reference.

ETHICS AND DISSEMINATION

The study was approved by the Institutional Review Board (IRB) at Johns Hopkins Bloomberg School of Public Health, Baltimore, USA (IRB00009714), the Committee on Human Research IRB at The George Washington University, Washington, DC, USA (081739), and the Ethical Review Board of the Nepal Health Research Council, Kathmandu, Nepal (174/2018).

TRIAL REGISTRATION NUMBER

NCT03668977.

The impact of antibiotic treatment for syphilis, chlamydia, and gonorrhoea during pregnancy on birth outcomes: A systematic review and meta-analysis

Background

Sexually transmissible infections are important causes of loss of health and lives in women and infants worldwide. This paper presents the methods and results of a systematic review that focuses on the impact of antibiotic treatment for syphilis, chlamydia, and gonorrhoea during pregnancy on birth outcomes for the Lives Saved Tool (LiST).

Methods

We searched PubMed, Embase, Cochrane Libraries, Global Health and Global Index Medicus for articles available until May 23rd, 2022. The search criteria focused on the impact of treatment for the three sexually transmitted infection among pregnant women. Nearly all the articles found were non-randomized studies.

Results

Treatment for pregnant women with active syphilis reduced the risk of preterm birth by 52% (95% CI = 42%-61%; 11 043 participants, 15 studies; low quality); stillbirth by 79% (95% CI = 65%-88%; 14 667 participants, eight studies; low quality); and low birth weight by 50% (95% CI = 41%-58%; 9778 participants, seven studies; moderate quality). Treatment for pregnant women with chlamydia infection reduced the risk of preterm birth by 42% (95% CI = 7%-64%; 5468 participants, seven studies; low quality) and might reduce the risk of low birth weight by 40% (95% CI = 0%-64%; 4684 participants, four studies; low quality). No studies provided data on treatment of gonorrhoea therefore no meta-analysis was conducted.

Conclusions

Because few studies adjusted for potential confounding factors, the overall quality of evidence was considered low. However, given the consistent and large effects, we recommend updating the estimated effect of timely detection and treatment for syphilis on preterm birth and stillbirth in the LiST model. More research is required to ascertain the effect of antibiotic treatment for chlamydia and gonorrhoea infection in pregnancy.

Small vulnerable newborns-big potential for impact

Despite major achievements in child survival, the burden of neonatal mortality has remained high and even increased in some countries since 1990. Currently, most neonatal deaths are attributable to being born preterm, small for gestational age (SGA), or with low birthweight (LBW). Besides neonatal mortality, these conditions are associated with stillbirth and multiple morbidities, with short-term and long-term adverse consequences for the newborn, their families, and society, resulting in a major loss of human capital. Prevention of preterm birth, SGA, and LBW is thus critical for global child health and broader societal development. Progress has, however, been slow, largely because of the global community's failure to agree on the definition and magnitude of newborn vulnerability and best ways to address it, to frame the problem attractively, and to build a broad coalition of actors and a suitable governance structure to implement a change. We propose a new definition and a conceptual framework, bringing preterm birth, SGA, and LBW together under a broader umbrella term of the small vulnerable newborn (SVN). Adoption of the framework and the unified definition can facilitate improved problem definition and improved programming for SVN prevention. Interventions aiming at SVN prevention would result in a healthier start for live-born infants, while also reducing the number of stillbirths, improving maternal health, and contributing to a positive economic and social development in the society.

Biological and pathological mechanisms leading to the birth of a small vulnerable newborn

The pathway to a thriving newborn begins before conception and continues in utero with a healthy placenta and the right balance of nutrients and growth factors that are timed and sequenced alongside hormonal suppression of labour until a mature infant is ready for birth. Optimal nutrition that includes adequate quantities of quality protein, energy, essential fats, and an extensive range of vitamins and minerals not only supports fetal growth but could also prevent preterm birth by supporting the immune system and alleviating oxidative stress. Infection, illness, undernourishment, and harmful environmental exposures can alter this trajectory leading to an infant who is too small due to either poor growth during pregnancy or preterm birth. Systemic inflammation suppresses fetal growth by interfering with growth hormone and its regulation of insulin-like growth factors. Evidence supports the prevention and treatment of several maternal infections during pregnancy to improve newborn health. However, microbes, such as Ureaplasma species, which are able to ascend the cervix and cause membrane rupture and chorioamnionitis, require new strategies for detection and treatment. The surge in fetal cortisol late in pregnancy is essential to parturition at the right time, but acute or chronically high maternal cortisol levels caused by psychological or physical stress could also trigger labour onset prematurely. In every pathway to the small vulnerable newborn, there is a possibility to modify the course of pregnancy by supporting improved nutrition, protection against infection, holistic maternal wellness, and healthy environments.

Prevalence and predictors of spontaneous preterm births in Nepal: findings from a prospective, population-based pregnancy cohort in rural Nepal-a secondary data analysis

OBJECTIVE

Preterm birth can have short-term and long-term complications for a child. Socioeconomic factors and pregnancy-related morbidities may be important to predict and prevent preterm births in low-resource settings. The objective of our study was to find prevalence and predictors of spontaneous preterm birth in rural Nepal.

DESIGN

This is a secondary observational analysis of trial data (registration number NCT01177111).

SETTING

Rural Sarlahi district, Nepal.

PARTICIPANTS

40 119 pregnant women enrolled from 9 September 2010 to 16 January 2017.

OUTCOME MEASURES

The outcome variable is spontaneous preterm birth. Generalized Estimating Equations Poisson regression with robust variance was fitted to present effect estimates as risk ratios.

RESULT

The prevalence of spontaneous preterm birth was 14.5% (0.5% non-spontaneous). Characteristics not varying in pregnancy associated with increased risk of preterm birth were maternal age less than 18 years (adjusted risk ratio=1.13, 95% CI: 1.02 to 1.26); being Muslim (1.53, 1.16 to 2.01); first pregnancy (1.15, 1.04 to 1.28); multiple births (4.91, 4.20 to 5.75) and male child (1.10, 1.02 to 1.17). Those associated with decreased risk were maternal education >5 years (0.81, 0.73 to 0.90); maternal height ≥150 cm (0.89, 0.81 to 0.98) and being from wealthier families (0.83, 0.74 to 0.93). Pregnancy-related morbidities associated with increased risk of preterm birth were vaginal bleeding (1.53, 1.08 to 2.18); swelling (1.37, 1.17 to 1.60); high systolic blood pressure (BP) (1.47, 1.08 to 2.01) and high diastolic BP (1.41, 1.17 to 1.70) in the third trimester. Those associated with decreased risk were respiratory problem in the third trimester (0.86, 0.79 to 0.94); having poor appetite, nausea and vomiting in the second trimester (0.86, 0.80 to 0.92) and third trimester (0.86, 0.79 to 0.94); and higher weight gain from second to third trimester (0.89, 0.87 to 0.90).

CONCLUSION

The prevalence of preterm birth is high in rural Nepal. Interventions that increase maternal education may play a role. Monitoring morbidities during antenatal care to intervene to reduce them through an effective health system may help reduce preterm birth.

Measurement of symphysis fundal height for gestational age estimation in low-to-middle-income countries: A systematic review and meta-analysis

In low- and middle-income countries (LMIC), measurement of symphysis fundal height (SFH) is often the only available method of estimating gestational age (GA) in pregnancy. This systematic review aims to summarize methods of SFH measurement and assess the accuracy of SFH for the purpose of GA estimation. We searched PubMed, EMBASE, Cochrane, Web of Science, POPLINE, and WHO Global Health Libraries from January 1980 through November 2021. For SFH accuracy, we pooled the variance of the mean difference between GA confirmed by ultrasound versus SFH. Of 1,003 studies identified, 37 studies were included. Nineteen different SFH measurement techniques and 13 SFH-to-GA conversion methods were identified. In pooled analysis of five studies (n = 5838 pregnancies), 71% (95% CI: 66-77%) of pregnancies dated by SFH were within ±14 days of ultrasound confirmed dating. Using the 1 cm SFH = 1wk assumption, SFH underestimated GA compared with ultrasound-confirmed GA (mean bias: -14.0 days) with poor accuracy (95% limits of agreement [LOA]: ±42.8 days; n = 3 studies, 2447 pregnancies). Statistical modeling of three serial SFH measurements performed better, but accuracy was still poor (95% LOA ±33 days; n = 4 studies, 4391 pregnancies). In conclusion, there is wide variation in SFH measurement and SFH-to-GA conversion techniques. SFH is inaccurate for estimating GA and should not be used for GA dating. Increasing access to quality ultrasonography early in pregnancy should be prioritized to improve gestational age assessment in LMIC.