Leveraging External Validation Data: The Challenges of Transporting Measurement Error Parameters.

Approaches to address measurement error frequently rely on validation data to estimate measurement error parameters (e.g., sensitivity and specificity). Acquisition of validation data can be costly, thus secondary use of existing data for validation is attractive. To use these external validation data, however, we may need to address systematic differences between these data and the main study sample. Here, we derive estimators of the risk and the risk difference that leverage external validation data to account for outcome misclassification. If misclassification is differential with respect to covariates that themselves are differentially distributed in the validation and study samples, the misclassification parameters are not immediately transportable. We introduce two ways to account for such covariates: (1) standardize by these covariates or (2) iteratively model the outcome. If conditioning on a covariate for transporting the misclassification parameters induces bias of the causal effect (e.g., M-bias), the former but not the latter approach is biased. We provide proof of identification, describe estimation using parametric models, and assess performance in simulations. We also illustrate implementation to estimate the risk of preterm birth and the effect of maternal HIV infection on preterm birth. Measurement error should not be ignored and it can be addressed using external validation data via transportability methods.

High rates of placental inflammation among samples collected by the Multi-Omics for Mothers and Infants consortium.

BACKGROUND: The Multi-Omics for Mothers and Infants consortium aims to improve birth outcomes. Preterm birth is a major obstetrical complication globally and causes significant infant and childhood morbidity and mortality. OBJECTIVE: We analyzed placental samples (basal plate, placenta or chorionic villi, and the chorionic plate) collected by the 5 Multi-Omics for Mothers and Infants sites, namely The Alliance for Maternal and Newborn Health Improvement Bangladesh, The Alliance for Maternal and Newborn Health Improvement Pakistan, The Alliance for Maternal and Newborn Health Improvement Tanzania, The Global Alliance to Prevent Prematurity and Stillbirth Bangladesh, and The Global Alliance to Prevent Prematurity and Stillbirth Zambia. The goal was to analyze the morphology and gene expression of samples collected from preterm and uncomplicated term births. STUDY DESIGN: The teams provided biopsies from 166 singleton preterm (<37 weeks' gestation) and 175 term (≥37 weeks' gestation) deliveries. The samples were fixed in formalin and paraffin embedded. Tissue sections from these samples were stained with hematoxylin and eosin and subjected to morphologic analyses. Other placental biopsies (n=35 preterm, 21 term) were flash frozen, which enabled RNA purification for bulk transcriptomics. RESULTS: The morphologic analyses revealed a surprisingly high rate of inflammation that involved the basal plate, placenta or chorionic villi, and the chorionic plate. The rate of inflammation in chorionic villus samples, likely attributable to chronic villitis, ranged from 25% (Pakistan site) to 60% (Zambia site) of cases. Leukocyte infiltration in this location vs in the basal plate or chorionic plate correlated with preterm birth. Our transcriptomic analyses identified 267 genes that were differentially expressed between placentas from preterm vs those from term births (123 upregulated, 144 downregulated). Mapping the differentially expressed genes onto single-cell RNA sequencing data from human placentas suggested that all the component cell types, either singly or in subsets, contributed to the observed dysregulation. Consistent with the histopathologic findings, gene ontology analyses highlighted the presence of leukocyte infiltration or activation and inflammatory responses in both the fetal and maternal compartments. CONCLUSION: The relationship between placental inflammation and preterm birth is appreciated in developed countries. In this study, we showed that this link also exists in developing geographies. In addition, among the participating sites, we found geographic- and population-based differences in placental inflammation and preterm birth, suggesting the importance of local factors.

Acceptability of a Randomized Trial of Anti-depressant Medication or Interpersonal Therapy for Treatment of Perinatal Depression in Women with HIV.

Postpartum depression (PPD) affects nearly 20% of postpartum women in Sub-Saharan Africa (SSA), where HIV prevalence is high. Depression is associated with worse HIV outcomes in non-pregnant adults and mental health disorders may worsen HIV outcomes for postpartum women and their infants. PPD is effectively treated with psychosocial or pharmacologic interventions; however, few studies have evaluated the acceptability of treatment modalities in SSA. We analyzed interviews with 23 postpartum women with HIV to assess the acceptability of two depression treatments provided in the context of a randomized trial. Most participants expressed acceptability of treatment randomization and study visit procedures. Participants shared perceptions of high treatment efficacy of their assigned intervention. They reported ongoing HIV and mental health stigma in their communities and emphasized the importance of social support from clinic staff. Our findings suggest a full-scale trial of PPD treatment will be acceptable among women with HIV in Zambia.

Comprehensive pregnancy monitoring with a network of wireless, soft, and flexible sensors in high- and low-resource health settings.

Vital signs monitoring is a fundamental component of ensuring the health and safety of women and newborns during pregnancy, labor, and childbirth. This monitoring is often the first step in early detection of pregnancy abnormalities, providing an opportunity for prompt, effective intervention to prevent maternal and neonatal morbidity and mortality. Contemporary pregnancy monitoring systems require numerous devices wired to large base units; at least five separate devices with distinct user interfaces are commonly used to detect uterine contractility, maternal blood oxygenation, temperature, heart rate, blood pressure, and fetal heart rate. Current monitoring technologies are expensive and complex with implementation challenges in low-resource settings where maternal morbidity and mortality is the greatest. We present an integrated monitoring platform leveraging advanced flexible electronics, wireless connectivity, and compatibility with a wide range of low-cost mobile devices. Three flexible, soft, and low-profile sensors offer comprehensive vital signs monitoring for both women and fetuses with time-synchronized operation, including advanced parameters such as continuous cuffless blood pressure, electrohysterography-derived uterine monitoring, and automated body position classification. Successful field trials of pregnant women between 25 and 41 wk of gestation in both high-resource settings (n = 91) and low-resource settings (n = 485) demonstrate the system's performance, usability, and safety.

Missing Outcome Data in Epidemiologic Studies.

Missing data are pandemic and a central problem for epidemiology. Missing data reduce precision and can cause notable bias. There remain too few simple published examples detailing types of missing data and illustrating their possible impact on results. Here we take an example randomized trial that was not subject to missing data and induce missing data to illustrate 4 scenarios in which outcomes are 1) missing completely at random, 2) missing at random with positivity, 3) missing at random without positivity, and 4) missing not at random. We demonstrate that accounting for missing data is generally a better strategy than ignoring missing data, which unfortunately remains a standard approach in epidemiology.

Risk of Adverse Birth Outcomes in Two Cohorts of Pregnant Women With HIV in Zambia.

BACKGROUND: A trial of progesterone to prevent preterm birth among HIV-infected Zambian women [Improving Pregnancy Outcomes with Progesterone (IPOP)] found no treatment effect, but the risk of the primary outcome was among the lowest ever documented in women with HIV. In this secondary analysis, we compare the risks of preterm birth (<37 weeks), stillbirth, and a composite primary outcome comprising the two in IPOP versus an observational pregnancy cohort [Zambian Preterm Birth Prevention Study (ZAPPS)] in Zambia, to evaluate reasons for the low risk in IPOP. METHODS: Both studies enrolled women before 24 gestational weeks, during August 2015-September 2017 (ZAPPS) and February 2018-January 2020 (IPOP). We used linear probability and log-binomial regression to estimate risk differences and risk ratios (RR), before and after restriction and standardization with inverse probability weights. RESULTS: The unadjusted risk of composite outcome was 18% in ZAPPS (N = 1450) and 9% in IPOP (N = 791) (RR = 2.0; 95% CI = 1.6, 2.6). After restricting and standardizing the ZAPPS cohort to the distribution of IPOP baseline characteristics, the risk remained higher in ZAPPS (RR = 1.6; 95% CI = 1.0, 2.4). The lower risk of preterm/stillbirth in IPOP was only partially explained by measured risk factors. CONCLUSIONS: Possible benefits in IPOP of additional monetary reimbursement, more frequent visits, and group-based care warrant further investigation.

Circulating angiogenic factors and HIV among pregnant women in Zambia: a nested case-control study.

BACKGROUND: Maternal HIV increases the risk of adverse birth outcomes including preterm birth, fetal growth restriction, and stillbirth, but the biological mechanism(s) underlying this increased risk are not well understood. We hypothesized that maternal HIV may lead to adverse birth outcomes through an imbalance in angiogenic factors involved in the vascular endothelial growth factor (VEGF) signaling pathway. METHODS: In a case-control study nested within an ongoing cohort in Zambia, our primary outcomes were serum concentrations of VEGF-A, soluble endoglin (sEng), placental growth factor (PlGF), and soluble fms-like tyrosine kinase-1 (sFLT-1). These were measured in 57 women with HIV (cases) and 57 women without HIV (controls) before 16 gestational weeks. We used the Wilcoxon rank-sum and linear regression controlling for maternal body mass index (BMI) and parity to assess the difference in biomarker concentrations between cases and controls. We also used logistic regression to test for associations between biomarker concentration and adverse pregnancy outcomes (preeclampsia, preterm birth, small for gestational age, stillbirth, and a composite of preterm birth or stillbirth). RESULTS: Compared to controls, women with HIV had significantly lower median concentrations of PlGF (7.6 vs 10.2 pg/mL, p = 0.02) and sFLT-1 (1647.9 vs 2055.6 pg/mL, p = 0.04), but these findings were not confirmed in adjusted analysis. PlGF concentration was lower among women who delivered preterm compared to those who delivered at term (6.7 vs 9.6 pg/mL, p = 0.03) and among those who experienced the composite adverse birth outcome (6.2 vs 9.8 pg/mL, p = 0.02). Median sFLT-1 concentration was lower among participants with the composite outcome (1621.0 vs 1945.9 pg/mL, p = 0.04), but the association was not significant in adjusted analysis. sEng was not associated with either adverse birth outcomes or HIV. VEGF-A was undetectable by Luminex in all specimens. CONCLUSIONS: We present preliminary findings that HIV is associated with a shift in the VEGF signaling pathway in early pregnancy, although adjusted analyses were inconclusive. We confirm an association between angiogenic biomarkers and adverse birth outcomes in our population. Larger studies are needed to further elucidate the role of HIV on placental angiogenesis and adverse birth outcomes.

Identifying Adolescent Girls and Young Women at High Risk for HIV Acquisition: A Risk Assessment Tool From the Girl Power-Malawi Study.

BACKGROUND: Prioritizing HIV prevention for adolescent girls and young women (AGYW) at high risk for HIV acquisition in sub-Saharan Africa (typically considered ≥3 per 100 person-years [PYs]) is urgently needed, but identifying these AGYW is challenging. We sought to assess and, if needed, enhance a risk assessment tool from the VOICE trial for identifying AGYW at high risk for HIV in Lilongwe, Malawi. METHODS: A multisite prospective cohort study was conducted among sexually active AGYW 15 to 24 years old at 4 health centers in 2016 to 2017. The VOICE tool was first applied and then updated by excluding variables that were not predictive and adding variables that were. Incidence rates (IRs), incidence rate ratios, 95% confidence intervals (CIs), area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were calculated. RESULTS: Seven hundred ninety-five participants experienced 14 seroconversions for 672 PYs (IR, 2.08 per 100 PYs; 95% CI, 1.23-3.52). The VOICE tool had moderate predictive ability (AUC, 0.64; 95% CI, 0.52-0.75). Maintaining 2 variables (genital ulcers and vaginal discharge), removing 5 sociodemographic variables, and adding 2 variables (ever pregnant and >5-year male-female age gap) enhanced performance (AUC, 0.79; 95% CI, 0.69-0.89). Thirty-five percent had a score of 0, 41% had a score of 1 to 2, and 24% had a score >3. A score >1 resulted in 100% sensitivity, 35.9% specificity, and an IR of 3.25 per 100 PYs. A score >3 resulted in 64.3% sensitivity, 76.8% specificity, and an IR of 5.89 per 100 PYs. CONCLUSIONS: A simple risk assessment tool identified a subset of AGYW in Malawi at high risk for HIV acquisition who may benefit from biomedical HIV prevention.

Intramuscular 17-hydroxyprogesterone caproate to prevent preterm birth among HIV-infected women in Zambia: study protocol of the IPOP randomized trial.

BACKGROUND: Each year, an estimated 15 million babies are born preterm, a global burden borne disproportionately by families in lower-income countries. Maternal HIV infection increases a woman's risk of delivering prematurely, and antiretroviral therapy (ART) may compound this risk. While prenatal progesterone prophylaxis prevents preterm birth among some high-risk women, it is unknown whether HIV-infected women could benefit from this therapy. We are studying the efficacy of progesterone supplementation to reduce the risk of preterm birth among pregnant women with HIV in Lusaka, Zambia. METHODS: The Improving Pregnancy Outcomes with Progesterone (IPOP) study is a Phase III double-masked, placebo-controlled, randomized trial of intramuscular 17-alpha hydroxprogesterone caproate (17P) to prevent preterm birth in HIV-infected women. A total of 800 women will be recruited prior to 24 weeks of gestation and randomly allocated to 17P or placebo administered by weekly intramuscular injection. The primary outcome will be a composite of live birth prior to 37 completed gestational weeks or stillbirth at any gestational age. Secondary outcomes will include very preterm birth (< 34 weeks), extreme preterm birth (< 28 weeks), small for gestational age (<10th centile), low birth weight (< 2500 g), and neonatal outcomes. In secondary analysis, we will assess whether specific HIV-related covariates, including the timing of maternal ART initiation relative to conception, is associated with progesterone's prophylactic efficacy, if any. DISCUSSION: We hypothesize that weekly prenatal 17P will reduce the risk of HIV-related preterm birth. An inexpensive intervention to prevent preterm birth among pregnant women with HIV could have substantial global public health impact. TRIAL REGISTRATION: NCT03297216 ; September 29, 2017.

Social determinants of access to minimally invasive hysterectomy: reevaluating the relationship between race and route of hysterectomy for benign disease.

BACKGROUND: Racial and socioeconomic disparities exist in access to medical and surgical care. Studies of national databases have demonstrated disparities in route of hysterectomy for benign indications, but have not been able to adjust for patient-level factors that affect surgical decision-making. OBJECTIVE: We sought to determine whether access to minimally invasive hysterectomy for benign indications is differential according to race independent of the effects of relevant subject-level confounding factors. The secondary study objective was to determine the association between socioeconomic status and ethnicity and access to minimally invasive hysterectomy. STUDY DESIGN: A cross-sectional study evaluated factors associated with minimally invasive hysterectomies performed for fibroids and/or abnormal uterine bleeding from 2010 through 2013 at 3 hospitals within an academic university health system in Philadelphia, PA. Univariate tests of association and multivariable logistic regression identified factors significantly associated with minimally invasive hysterectomy compared to the odds of treatment with the referent approach of abdominal hysterectomy. RESULTS: Of 1746 hysterectomies evaluated meeting study inclusion criteria, 861 (49%) were performed abdominally, 248 (14%) vaginally, 310 (18%) laparoscopically, and 327 (19%) with robot assistance. In univariate analysis, African American race (odds ratio, 0.80; 95% confidence interval, 0.65-0.97) and Hispanic ethnicity (odds ratio, 0.63; 95% confidence interval, 0.39-1.00) were associated with lower odds of any minimally invasive hysterectomy relative to abdominal hysterectomy. In analyses adjusted for age, body mass index, income quartile, obstetrical and surgical history, uterine weight, and additional confounding factors, African American race was no longer a risk factor for reduced minimally invasive hysterectomy (odds ratio, 0.82; 95% confidence interval, 0.61-1.10), while Hispanic ethnicity (odds ratio, 0.45; 95% confidence interval, 0.27-0.76) and Medicaid enrollment (odds ratio, 0.59; 95% confidence interval, 0.38-0.90) were associated with significantly lower odds of treatment with any minimally invasive hysterectomy. In adjusted analyses, African American women had nearly half the odds of receiving robot-assisted hysterectomy compared to whites (adjusted odds ratio, 0.57; 95%, confidence interval 0.39-0.82), while no differences were noted with other hysterectomy routes. Medicaid enrollment (compared to private insurance; odds ratio, 0.51; 95% confidence interval, 0.28-0.94) and lowest income quartile (compared to highest income quartile; odds ratio, 0.57; 95% confidence interval, 0.38-0.85) were also associated with diminished odds of robot-assisted hysterectomy. CONCLUSION: When accounting for the effect of numerous pertinent demographic and clinical factors, the odds of undergoing minimally invasive hysterectomy were diminished in women of Hispanic ethnicity and in those enrolled in Medicaid but were not discrepant along racial lines. However, both racial and socioeconomic disparities were observed with respect to access to robot-assisted hysterectomy despite the availability of robotic assistance in all hospitals treating the study population. Strategies to ensure equal access to all minimally invasive routes for all women should be explored to align delivery of care with the evidence supporting the broad implementation of these procedures as safe, cost-effective, and highly acceptable to patients.

Association of maternal prenatal copper concentration with gestational duration and preterm birth: a multicountry meta-analysis.

BACKGROUND: Copper (Cu), an essential trace mineral regulating multiple actions of inflammation and oxidative stress, has been implicated in risk for preterm birth (PTB). OBJECTIVES: This study aimed to determine the association of maternal Cu concentration during pregnancy with PTB risk and gestational duration in a large multicohort study including diverse populations. METHODS: Maternal plasma or serum samples of 10,449 singleton live births were obtained from 18 geographically diverse study cohorts. Maternal Cu concentrations were determined using inductively coupled plasma mass spectrometry. The associations of maternal Cu with PTB and gestational duration were analyzed using logistic and linear regressions for each cohort. The estimates were then combined using meta-analysis. Associations between maternal Cu and acute-phase reactants (APRs) and infection status were analyzed in 1239 samples from the Malawi cohort. RESULTS: The maternal prenatal Cu concentration in our study samples followed normal distribution with mean of 1.92 µg/mL and standard deviation of 0.43 µg/mL, and Cu concentrations increased with gestational age up to 20 wk. The random-effect meta-analysis across 18 cohorts revealed that 1 µg/mL increase in maternal Cu concentration was associated with higher risk of PTB with odds ratio of 1.30 (95% confidence interval [CI]: 1.08, 1.57) and shorter gestational duration of 1.64 d (95% CI: 0.56, 2.73). In the Malawi cohort, higher maternal Cu concentration, concentrations of multiple APRs, and infections (malaria and HIV) were correlated and associated with greater risk of PTB and shorter gestational duration. CONCLUSIONS: Our study supports robust negative association between maternal Cu and gestational duration and positive association with risk for PTB. Cu concentration was strongly correlated with APRs and infection status suggesting its potential role in inflammation, a pathway implicated in the mechanisms of PTB. Therefore, maternal Cu could be used as potential marker of integrated inflammatory pathways during pregnancy and risk for PTB.

Maternal COVID-19 infection and associated factors: A cross-sectional study.

BACKGROUND: Since the declaration of COVID-19 as a global pandemic, several studies have been conducted to examine associated factors. However, few studies have focused on pregnant women infected with COVID-19 in sub-Saharan Africa. Therefore, this study investigated the prevalence and factors associated with COVID-19 infection among pregnant women at the Levy Mwanawasa University Teaching Hospital and Women and Newborn Hospital of the University Teaching Hospitals in Lusaka, Zambia. METHODS: A cross-sectional study was conducted between March and July 2021. Women were recruited as they presented for antenatal care. Data was collected using a structured questionnaire to capture variables of interest (socio-demographic, clinical and obstetric). COVID-19 diagnosis was made using a nasopharyngeal swab by PCR test. Multivariable logistic regression was used to control for confounding and calculate the odds ratios for each explanatory variable and respective 95% confidence intervals. RESULTS: The study enrolled 352 participants with a mean (standard deviation [SD]) age of 30.1 years (5.6). One hundred thirty of 352 (36.9%; 95% CI: 31.9 to 42.2) participants had a confirmed positive SARS-CoV-2 test result. At univariable analysis, factors associated with COVID-19 were increased gestational age, education status and maternal HIV serostatus. Women with a secondary level of education were less likely to have COVID-19 infection than those with a primary level of education (AOR = 0.23, 95% CI: 0.09-0.63). On the other hand, a one-week increase in gestational age was associated with higher odds of COVID-19 infection (AOR = 1.03, 95% CI: 1.01-1.06). CONCLUSION: The results showed that the prevalence of COVID-19 infection among pregnant women was 36.9% and was associated with increased gestational age and a lower level of education. To mitigate adverse maternal outcomes, there is a need to screen for COVID-19 strictly and broadly monitor prenatal women presenting for healthcare.

Maternal mid-upper arm circumference to predict small for gestational age: Findings in a Zambian cohort.

OBJECTIVE: To compare the performance of mid upper arm circumference (MUAC) and body mass index (BMI) for prediction of small for gestational age (SGA) in Zambia. METHODS: This is a secondary analysis of an ongoing clinical cohort that included women with a single gestation and MUAC measured before 24 weeks of pregnancy. We assessed relationships between maternal MUAC and birth weight centile using regression. The performance of MUAC and BMI to predict SGA was compared using receiver operating characteristic curves and the effect of maternal HIV was investigated in sub-group analyses. RESULTS: Of 1117 participants, 847 (75%) were HIV-negative (HIV-) and 270 (24%) were HIV-positive (HIV+). Seventy-four (7%) delivered severe SGA infants (<3rd centile), of whom 56 (76%) were HIV- and 18 (24%) were HIV+ (odds ratio [OR] 1.01, 95% confidence interval [CI] 0.58-1.75). MUAC was associated with higher birth weight centile (+1.2 centile points, 95% CI 0.7-1.6; P < 0.001); this relationship was stronger among HIV+ women (+1.7 centile points, 95% CI 0.8-2.6; P < 0.001) than HIV- women (+0.9 centile points, 95% CI 0.4-1.4; P = 0.001). The discriminatory power was similar, albeit poor (area under the curve [AUC] < 0.7), between MUAC and BMI for the prediction of SGA. In stratified analysis, MUAC and BMI showed excellent discrimination predicting severe SGA among HIV+ (AUC 0.83 and 0.81, respectively) but not among HIV- women (AUC 0.64 and 0.63, respectively). CONCLUSION: Maternal HIV infection increased the discrimination of both early pregnancy MUAC and BMI for prediction of severe SGA in Zambia. CLINICAL TRIAL NUMBER: ClinicalTrials.gov (NCT02738892).

Different effects for different questions: An illustration using short cervix and the risk of preterm birth.

OBJECTIVE: To illustrate the difference between exposure effects and population attributable effects. METHODS: We examined the effect of mid-pregnancy short cervical length (<25 mm) on preterm birth using data from a prospective cohort of pregnant women in Lusaka, Zambia. Preterm birth was live birth or stillbirth before 37 weeks of pregnancy. For estimation, we used multivariable regression and parametric g-computation. RESULTS: Among 1409 women included in the analysis, short cervix was rare (2.4%); 13.6% of births were preterm. Exposure effect estimates were large (marginal risk ratio 2.86, 95% confidence interval [CI] 1.80-4.54), indicating that the preterm birth risk was substantially higher among women with a short cervix compared with women without a short cervix. However, the population attributable effect estimates were close to the null (risk ratio 1.06, 95% CI 1.02-1.10), indicating that an intervention to counteract the impact of short cervix on preterm birth would have minimal effect on the population risk of preterm birth. CONCLUSION: Although authors often refer to "the" effect, there are actually different types of effects, as we have illustrated here. In planning research, it is important to consider which effect to estimate to ensure that the estimate aligns with the research objective.

Progesterone and prolactin levels in pregnant women living with HIV who delivered preterm and low birthweight infants: A nested case-control study.

BACKGROUND: Antiretroviral therapy (ART) is associated with high rates of adverse birth outcomes, including preterm birth and low birthweight. Studies suggest that progesterone and prolactin may play important intermediary roles. METHODS: We analyzed data from the Antenatal Component of the PROMISE trial, a multi-center study of pregnant women taking antiretroviral regimens (lopinavir/ritonavir-containing ART or zidovudine alone) to prevent mother-to-child HIV transmission. In a nested case-control study, we compared data from women who gave birth to preterm (<37 weeks gestation) and/or low birthweight (<2500 g) infants to matched individuals who did not. We measured serum progesterone and prolactin at 24-34 weeks gestation. We used conditional logistic regression to describe relationships between hormone levels, birth outcomes, and antiretroviral regimens. RESULTS: 299 women and their newborns were included (146 cases, 153 controls). When compared to women receiving zidovudine alone, those on ART had higher odds of progesterone levels under the 10th percentile (adjusted odds ratio [AOR]:2.34, 95%CI:1.41-3.89) and 25th percentile (AOR:2.07, 95%CI:1.46-2.94). However, higher levels of progesterone-rather than lower levels-were associated with our composite case outcome at the 10th percentile (AOR:1.88, 95%CI:0.77-4.59) and 25th percentile (AOR:1.96, 95%CI:1.06-3.61). Associations were not observed between prolactin, antiretroviral regimen, and birth outcomes. CONCLUSION: We observed lower progesterone levels among women allocated to ART regimens; however, higher progesterone levels were associated with preterm birth and/or low birthweight. While features of the study design may have contributed to these findings, they nevertheless highlight the potentially complex mechanisms underpinning adverse birth outcomes and HIV.

Comparison of Masimo Total Hemoglobin SpHb® continuous non-invasive hemoglobin monitoring device with laboratory complete blood count measurement using venous sample: Protocol for an observational substudy of the Pregnancy Risk and Infant Surveillance and Measurement Alliance Maternal and Newborn Health (PRISMA MNH) study.

Background: The Masimo Total Hemoglobin SpHb® is a continuous and non-invasive handheld device to measure hemoglobin levels. Previous research has found that SpHb is able to accurately detect hemoglobin levels in adult patients with a similar degree of bias and standard deviation to point-of-care invasive method measurements. Generally, limited clinical evidence, lack of validation of Masimo at higher than and lower than hemoglobin threshold values, and scientific consensus supporting the use of Masimo for accurate hemoglobin testing for the diagnosis of anemia during pregnancy calls for further research. Methods and analysis: The proposed prospective cohort will be nested within the ongoing Pregnancy Risk and Infant Surveillance and Measurement Alliance (PRISMA) Maternal and Newborn Health (MNH) study. Three study sites (located in Zambia, Kenya, and Pakistan) will participate and collect hemoglobin data at five time points (<20 weeks, 20 weeks, 28 weeks, 36 weeks' gestation, and six weeks postpartum). We will measure hemoglobin using a venous blood sample via hematology auto-analyzer complete blood count (gold standard) and the non-invasive device. The primary objective is to assess agreement between Masimo total hemoglobin and complete blood count and on a continuous scale using Intraclass Correlation Coefficient and Bland-Altman Analysis. The second objective is to assess agreement between the two measures on a binary scale using Positive Percentage Agreement and Negative Percentage Agreement, Cohen's Kappa, and McNemar Test. On an ordinal scale, agreement will be measured using Weighted Cohen's Kappa and Harrel's Concordance Index. Lastly, we will assess factors that might affect the accuracy of Masimo total hemoglobin using linear mixed models. Conclusions: The primary aim of this study is to assess the validity of the non-invasive Masimo device compared to the gold standard method of invasive hemoglobin measurements during pregnancy and postpartum periods for the diagnosis of anemia.

Development and external validation of machine learning algorithms for postnatal gestational age estimation using clinical data and metabolomic markers.

BACKGROUND: Accurate estimates of gestational age (GA) at birth are important for preterm birth surveillance but can be challenging to obtain in low income countries. Our objective was to develop machine learning models to accurately estimate GA shortly after birth using clinical and metabolomic data. METHODS: We derived three GA estimation models using ELASTIC NET multivariable linear regression using metabolomic markers from heel-prick blood samples and clinical data from a retrospective cohort of newborns from Ontario, Canada. We conducted internal model validation in an independent cohort of Ontario newborns, and external validation in heel prick and cord blood sample data collected from newborns from prospective birth cohorts in Lusaka, Zambia and Matlab, Bangladesh. Model performance was measured by comparing model-derived estimates of GA to reference estimates from early pregnancy ultrasound. RESULTS: Samples were collected from 311 newborns from Zambia and 1176 from Bangladesh. The best-performing model accurately estimated GA within about 6 days of ultrasound estimates in both cohorts when applied to heel prick data (MAE 0.79 weeks (95% CI 0.69, 0.90) for Zambia; 0.81 weeks (0.75, 0.86) for Bangladesh), and within about 7 days when applied to cord blood data (1.02 weeks (0.90, 1.15) for Zambia; 0.95 weeks (0.90, 0.99) for Bangladesh). CONCLUSIONS: Algorithms developed in Canada provided accurate estimates of GA when applied to external cohorts from Zambia and Bangladesh. Model performance was superior in heel prick data as compared to cord blood data.

Comparative predictive power of serum vs plasma proteomic signatures in feto-maternal medicine.

BACKGROUND: Blood proteins are frequently measured in serum or plasma, because they provide a wealth of information. Differences in the ex vivo processing of serum and plasma raise concerns that proteomic health and disease signatures derived from serum or plasma differ in content and quality. However, little is known about their respective power to predict feto-maternal health outcomes. Predictive power is a sentinel characteristic to determine the clinical use of biosignatures. OBJECTIVE: This study aimed to compare the power of serum and plasma proteomic signatures to predict a physiological pregnancy outcome. STUDY DESIGN: Paired serum and plasma samples from 73 women were obtained from biorepositories of a multinational prospective cohort study on pregnancy outcomes. Gestational age at the time of sampling was the predicted outcome, because the proteomic signatures have been validated for such a prediction. Multivariate and cross-validated models were independently derived for serum and plasma proteins. RESULTS: A total of 1116 proteins were measured in 88 paired samples from 73 women with a highly multiplexed platform using proximity extension technology (Olink Proteomics Inc, Watertown, MA). The plasma proteomic signature showed a higher predictive power (R=0.64; confidence interval, 0.42-0.79; P=3.5×10-6) than the serum signature (R=0.45; confidence interval, 0.18-0.66; P=2.2×10-3). The serum signature was validated in plasma with a similar predictive power (R=0.58; confidence interval, 0.34-0.75; P=4.8×10-5), whereas the plasma signature was validated in serum with reduced predictive power (R=0.53; confidence interval, 0.27-0.72; P=2.6×10-4). Signature proteins largely overlapped in the serum and plasma, but the strength of association with gestational age was weaker for serum proteins. CONCLUSION: Findings suggest that serum proteomics are less informative than plasma proteomics. They are compatible with the view that the partial ex-vivo degradation and modification of serum proteins during sample processing are an underlying reason. The rationale for collecting and analyzing serum and plasma samples should be carefully considered when deriving proteomic biosignatures to ascertain that specimens of the highest scientific and clinical yield are processed. Findings suggest that plasma is the preferred matrix.

Multiomic signals associated with maternal epidemiological factors contributing to preterm birth in low- and middle-income countries.

Preterm birth (PTB) is the leading cause of death in children under five, yet comprehensive studies are hindered by its multiple complex etiologies. Epidemiological associations between PTB and maternal characteristics have been previously described. This work used multiomic profiling and multivariate modeling to investigate the biological signatures of these characteristics. Maternal covariates were collected during pregnancy from 13,841 pregnant women across five sites. Plasma samples from 231 participants were analyzed to generate proteomic, metabolomic, and lipidomic datasets. Machine learning models showed robust performance for the prediction of PTB (AUROC = 0.70), time-to-delivery (r = 0.65), maternal age (r = 0.59), gravidity (r = 0.56), and BMI (r = 0.81). Time-to-delivery biological correlates included fetal-associated proteins (e.g., ALPP, AFP, and PGF) and immune proteins (e.g., PD-L1, CCL28, and LIFR). Maternal age negatively correlated with collagen COL9A1, gravidity with endothelial NOS and inflammatory chemokine CXCL13, and BMI with leptin and structural protein FABP4. These results provide an integrated view of epidemiological factors associated with PTB and identify biological signatures of clinical covariates affecting this disease.

Seroreduction of syphilis non-treponemal titers during pregnancy for women with and without HIV co-infection.

OBJECTIVE: To evaluate the effect of HIV co-infection on non-treponemal titers during pregnancy in women with syphilis. METHODS: This is a secondary analysis of pregnant women with syphilis in the prospective, observational Zambian Preterm Birth Prevention Study (ZAPPS). Treponemal (Treponema pallidum particle agglutination) and non-treponemal (rapid plasma reagin; RPR) testing were performed on serum biospecimens, resulting in 47 participants with serologically confirmed syphilis (27 HIV-positive, 20 HIV-negative). The primary outcome, achievement of RPR titer seroreduction during pregnancy, was analyzed by logistic regression. Secondary outcomes included overall titer reduction, seroreduction rate, serologic cure, and adverse pregnancy outcomes. RESULTS: Seroreduction of RPR titer occurred in 78% (21/27) of women with HIV versus 45% (9/20) of women without (adjusted odds ratio 4.66; 95% confidence interval [CI] 1.14 - 19.08). Overall RPR titer reduction, rate of seroreduction per week, and the proportion achieving serologic cure each trended higher among women with HIV compared with those without HIV. There was a trend toward decreased stillbirth incidence in participants achieving seroreduction (odds ratio 0.15, 95% CI 0.01-1.58). CONCLUSION: HIV co-infection in this cohort of Zambian women with syphilis was associated with greater odds of RPR titer seroreduction during pregnancy. Pregnant women with syphilis and HIV may not be at increased risk for a delayed syphilis treatment response compared with women without HIV.