A Novel Intervention to Increase Postpartum Primary Care Engagement: A Randomized Clinical Trial

Importance

Over 30% of pregnant people have at least one chronic medical condition, and nearly 20% develop gestational diabetes or pregnancy-related hypertension, increasing the risk of future chronic disease. While these individuals are often monitored closely during pregnancy, they face significant barriers when transitioning to primary care following delivery, due in part to a lack of health care support for this transition.

Objective

To evaluate the impact of an intervention designed to improve postpartum primary care engagement by reducing patient administrative burden and information gaps.

Design

Individual-level randomized controlled trial.

Setting

One hospital-based and five community-based outpatient obstetric clinics affiliated with a large academic medical center.

Participants

Participants included English- and Spanish-speaking pregnant or recently postpartum adults with obesity, anxiety, depression, diabetes mellitus, chronic hypertension, gestational diabetes, or pregnancy-related hypertension, and a primary care clinician (PCP) listed in their electronic health record (EHR).

Intervention

A behavioral economics-informed intervention bundle, including default scheduling of postpartum PCP appointments and patient messages and reminders with tailored language.

Main Outcome

Completion of a PCP visit for routine or chronic condition care within 4 months of delivery.

Results

360 patients were randomized (Control: N=176, Intervention: N=184). PCP visit completion within 4 months occurred in 22.0% (95% confidence interval (CI) 16.4-28.8%) in the control group and 40.0% (95%CI 33.1-47.4%) in the intervention group. In regression models accounting for randomization strata, the intervention increased PCP visit completion by 18.7 percentage points (95%CI 10.7-29.1). The intervention also significantly decreased postpartum readmissions, increased receipt of blood pressure, weight, and mood screenings, and increased PCP-documented plans for contraception and mental health.

Conclusions and Relevance

The current lack of support for postpartum transitions to primary care is a missed opportunity to improve recently pregnant individual's short- and long-term health. This study found that default PCP visit scheduling, tailored messages, and reminders can substantially improve postpartum primary care engagement for individuals with or at high risk for chronic disease. Efforts to reduce patient administrative burdens may be relatively low-resource, high-impact approaches to improving postpartum health and wellbeing.

Trial Registration

NCT05543265.

The simultaneous occurrence of gestational diabetes and hypertensive disorders of pregnancy affects fetal growth and neonatal morbidity

BACKGROUND

Gestational diabetes is associated with increased risk of hypertensive disorders of pregnancy, but there are limited data on fetal growth and neonatal outcomes when both conditions are present.

OBJECTIVE

We evaluated the risk of abnormal fetal growth and neonatal morbidity in pregnancies with co-occurrence of gestational diabetes and hypertensive disorders of pregnancy.

STUDY DESIGN

In a retrospective study of 47,093 singleton pregnancies, we compared the incidence of appropriate for gestational age birthweight in pregnancies affected by gestational diabetes alone, hypertensive disorders of pregnancy alone, or both gestational diabetes and hypertensive disorders of pregnancy with that in pregnancies affected by neither disorder using generalized estimating equations (covariates: maternal age, nulliparity, body mass index, insurance type, race, marital status, and prenatal care site). Secondary outcomes were large for gestational age birthweight, small for gestational age birthweight, and a neonatal morbidity composite outcome (stillbirth, hypoglycemia, hyperbilirubinemia, respiratory distress, encephalopathy, preterm delivery, neonatal death, and neonatal intensive care unit admission).

RESULTS

The median (interquartile range) birthweight percentile in pregnancies with both gestational diabetes and hypertensive disorders of pregnancy (50 [24.0-78.0]; N=179) was similar to that of unaffected pregnancies (50 [27.0-73.0]; N=35,833). However, the absolute rate of appropriate for gestational age birthweight was lower for gestational diabetes/hypertensive disorders of pregnancy co-occurrence (78.2% vs 84.9% for unaffected pregnancies). Adjusted analyses showed decreased odds of appropriate for gestational age birthweight in pregnancies with both gestational diabetes and hypertensive disorders of pregnancy compared with unaffected pregnancies (adjusted odds ratio, 0.72 [95% confidence interval, 0.52-1.00]; P=.049), and in pregnancies complicated by gestational diabetes alone (adjusted odds ratio, 0.78 [0.68-0.89]; P<.001) or hypertensive disorders of pregnancy alone (adjusted odds ratio, 0.73 [0.66-0.81]; P<.001). The absolute risk of large for gestational age birthweight was greater in pregnancies with both gestational diabetes and hypertensive disorders of pregnancy (14.5%) than in unaffected pregnancies (8.2%), without apparent difference in the risk of small for gestational age birthweight (7.3% vs 6.9%). However, in adjusted models comparing pregnancies with gestational diabetes/hypertensive disorders of pregnancy co-occurrence with unaffected pregnancies, neither an association with large for gestational age birthweight (adjusted odds ratio, 1.33 [0.88-2.00]; P=.171) nor small for gestational age birthweight (adjusted odds ratio, 1.32 [0.80-2.19]; P=.293) reached statistical significance. Gestational diabetes/hypertensive disorders of pregnancy co-occurrence carried an increased risk of neonatal morbidity that was greater than that observed with either condition alone (gestational diabetes/hypertensive disorders of pregnancy: adjusted odds ratio, 3.13 [2.35-4.17]; P<.001; gestational diabetes alone: adjusted odds ratio, 2.01 [1.78-2.27]; P<.001; hypertensive disorders of pregnancy alone: adjusted odds ratio, 1.38 [1.26-1.50]; P<.001).

CONCLUSION

Although pregnancies with both gestational diabetes and hypertensive disorders of pregnancy have a similar median birthweight percentile to those affected by neither condition, pregnancies concurrently affected by both conditions have a higher risk of abnormal fetal growth and neonatal morbidity.

Performance of a Maternal Risk Stratification System for Predicting Low Apgar Scores

OBJECTIVE

 Maternal risk stratification systems are increasingly employed in predicting and preventing obstetric complications. These systems focus primarily on maternal morbidity, and few tools exist to stratify neonatal risk. We sought to determine if a maternal risk stratification score was associated with neonatal morbidity.

STUDY DESIGN

 Retrospective cohort study of patients with liveborn infants born at ≥24 weeks at four hospitals in one health system between January 1, 2020, and December 31, 2020. The Expanded Obstetric Comorbidity Score (EOCS) is used as the maternal risk score. The primary neonatal outcome was 5-minute Apgar <7. Logistic regression models determined associations between EOCS and neonatal morbidity. Secondary analyses were performed, including stratifying outcomes by gestational age and limiting analysis to "low-risk" term singletons. Model discrimination assessed using the area under the receiver operating characteristic curves (AUC) and calibration via calibration plots.

RESULTS

 A total of 14,497 maternal-neonatal pairs were included; 236 (1.6%) had 5-minute Apgar <7; EOCS was higher in 5-minute Apgar <7 group (median 41 vs. 11, p < 0.001). AUC for EOCS in predicting Apgar <7 was 0.72 (95% Confidence Interval (CI) 0.68, 0.75), demonstrating relatively good discrimination. Calibration plot revealed that those in the highest EOCS decile had higher risk of neonatal morbidity (7.6 vs. 1.7%, p < 0.001). When stratified by gestational age, discrimination weakened with advancing gestational age: AUC 0.70 for <28 weeks, 0.63 for 28 to 31 weeks, 0.64 for 32 to 36 weeks, and 0.61 for ≥37 weeks. When limited to term low-risk singletons, EOCS had lower discrimination for predicting neonatal morbidity and was not well calibrated.

CONCLUSION

 A maternal morbidity risk stratification system does not perform well in most patients giving birth, at low risk for neonatal complications. The findings suggest that the association between EOCS and 5-minute Apgar <7 likely reflects a relationship with prematurity. This study cautions against intentional or unintentional extrapolation of maternal morbidity risk for neonatal risk, especially for term deliveries.

KEY POINTS

· EOCS had moderate discrimination for Apgar <7.. · Predictive performance declined when limited to low-risk term singletons.. · Relationship between EOCS and Apgar <7 was likely driven by prematurity..

Gross and Histologic Placental Abnormalities Associated With Neonatal Hypoxic-Ischemic Encephalopathy

OBJECTIVE

To elucidate particular placental pathology findings that are associated with hypoxic ischemic encephalopathy (HIE) and determine which patterns are associated with adverse fetal/neonatal outcomes.

STUDY DESIGN

Multi-institutional retrospective case-control study of newborns with HIE (2002-2022) and controls. Four perinatal pathologists performed gross and histologic evaluation of placentas of cases and controls.

RESULTS

A total of 265 placentas of neonates with HIE and 122 controls were examined. Infants with HIE were more likely to have anatomic umbilical cord abnormalities (19.7% vs 7.4%, P = .003), fetal inflammatory response in the setting of amniotic fluid infection (27.7% vs 13.9%, P = .004), and fetal vascular malperfusion (30.6% vs 9.0%, P = <.001) versus controls. Fetal vascular malperfusion with maternal vascular malperfusion was more common in those who died of disease (P = .01).

CONCLUSION

Placental pathology examination of neonates with HIE may improve our understanding of this disorder and its adverse outcomes.

Helping Us Grow Stronger (HUGS)/Abrazos: a community-based initiative improved perinatal mental health in an urban cohort

BACKGROUND

Targeted programs aimed at improving maternal mental health, particularly among those exposed to social determinants of health, are increasingly critical since the onset of the COVID-19 pandemic, yet the impact of such programs is poorly understood.

OBJECTIVE

This study aimed to evaluate the impact of a novel, language-concordant community-based program on perinatal mental health.

STUDY DESIGN

We conducted a prospective cohort study of peripartum individuals referred to a new community-based intervention known as Helping Us Grow Stronger (HUGS/Abrazos). Participants received up to 4 remote sessions with a cognitive behavioral therapy trained social worker, up to 3 resource navigation sessions with a community health worker, and direct relief with a grocery gift card and care package. Before and after the program, participants completed validated survey instruments to assess mental health and social determinants of health.

RESULTS

A total of 178 participants were assessed after program completion, including 133 who were assessed before and after the program. The cohort was composed of 62.9% Hispanic or Latinx participants with a mean age of 29.8 year (standard error of mean, 0.46). There were high rates of food insecurity (111/178; 62.4%), experiences of discrimination (119/178; 66.9%), and SARS-CoV-2 infection (105/178; 59.0%). The program was associated with statistically significant improvements in the Edinburgh Postnatal Depression scores (baseline [mean±standard error of mean], 8.44±0.55 vs 6.77±0.51 after program completion; P=.0001) and Perceived Stress Scale scores (baseline, 15.2±0.74 vs 14.0±0.71; P=.035). Participants exposed to stressors including food insecurity and experiences of discrimination had higher baseline depression, stress, and anxiety scores. Those with experiences of discrimination, food insecurity, and SARS-CoV-2 infection during pregnancy were more likely to have improvements in mental health scores postintervention.

CONCLUSION

In this diverse urban cohort, a novel community-based intervention was associated with improvements in depressive symptoms, perceived stress, and anxiety, particularly among those with social determinants of health.

Glycated Albumin and Glycemia in Pregnancy and Postpartum: A Pilot Study

OBJECTIVE

 Percent glycated albumin (%GAlb) is a marker of glycemia over the past 2 to 3 weeks in nonpregnant individuals. Longitudinal changes in %GAlb extending throughout pregnancy and postpartum (PP) have not been described. We aimed to describe levels of %GAlb throughout pregnancy and PP and relationships with glycemia.

STUDY DESIGN

 Fifty women among those in the Study of Pregnancy Regulation of INsulin and Glucose cohort underwent 75-g oral glucose tolerance tests (OGTTs) at a mean of 13 weeks (V1) and 26 weeks (V2) of gestation and 11 weeks' PP. %GAlb was measured on frozen plasma samples.

RESULTS

 Total albumin decreased from V1 to V2 and increased PP to levels higher than at V1. %GAlb declined between V1 and V2 (β = - 0.63% 95% CI [-0.8, -0.6] p < 0.001) and remained stable between V2 and PP (β = - 0.04% [-0.3, 0.2] p = 0.78). Body mass index (BMI) was inversely related to %GAlb in pregnancy (V1: rho = - 0.5, p = 0.0001; V2 rho = - 0.4, p = 0.006), but not PP (rho = - 0.15, p = 0.31). The longitudinal changes in %GAlb persisted after adjusting for BMI. Neither glycemia measurements nor hemoglobin A1c were associated with %GAlb at any time point, and adjustments for BMI did not reveal additional associations.

CONCLUSION

 %GAlb decreases between early and late gestation and remains decreased PP, despite a PP increase in total albumin above early pregnancy values. Given the lack of correlation with OGTT values or A1c, %GAlb is unlikely to be useful in assessing glycemia in pregnant or PP women.

KEY POINTS

· Changes in %GAlb extending to the postpartum period have not been described.. · %GAlb decreases in pregnancy and remains decreased postpartum, despite a postpartum increase in total albumin above early pregnancy values.. · Glycemia measurements nor A1c were associated with %GAlb at any time point, therefore, %GAlb is unlikely to be useful in assessing glycemia in pregnant or postpartum women..

Maternal anemia is associated with adverse maternal and neonatal outcomes in Mbarara, Uganda

PURPOSE

Maternal anemia is a significant risk factor for maternal morbidity and mortality, increasing risk of preterm birth, intrauterine growth restriction, stillbirth, and death. Moderate and severe anemia in pregnancy is defined as hemoglobin (Hb) <10 g/dl and Hb < 7 g/dl, respectively. We aimed to characterize the association of maternal anemia with maternal, neonatal, and placental outcomes in a resource-limited setting.

METHODS

Data were collected from a prospective cohort of 352 pregnant women at a tertiary academic Ugandan hospital. One hundred and seventy-six (50%) of women were living with HIV. Hemoglobin was measured in labor, and placentas were collected postpartum. Maternal outcomes included mode of delivery, hemorrhage, blood transfusion, intensive care unit admission, and maternal mortality. Neonatal outcomes included gestational age at delivery, birthweight, stillbirth, and neonatal mortality. Placental descriptors included weight and thickness. Categorical variables were analyzed using Chi-squared and Fisher's exact tests.

RESULTS

Hemoglobin < 10 g/dl, was present in 17/352 (5%) of women. Significantly more women with moderate or severe anemia were HIV-infected: 14/17 (82%) versus 162/335 (48%) (p = .006). Blood transfusions (2/17, 12% versus 5/335, 2%, p = .04) and neonatal deaths (2/17, 12% versus 9/335, 3%, p = .01) were more common in the anemia group. Placental thickness was lower in the anemia group (1.4 cm versus 1.7 cm, p = .04).

CONCLUSIONS

Moderate and severe anemia was associated with maternal HIV infection, maternal blood transfusion, neonatal death, and decreased placental thickness. The overall rate of moderate and severe anemia among this cohort was lower than previously reported.

Sex-specific impact of maternal obesity on fetal placental macrophages and cord blood triglycerides

INTRODUCTION

Maternal obesity is associated with increased risk of offspring obesity and cardiometabolic disease. Altered fetoplacental immune programming is a potential candidate mechanism. Differences in fetal placental macrophages, or Hofbauer cells (HBCs), have been observed in maternal obesity, and lipid metabolism is a key function of resident macrophages that may be deranged in inflammation/immune activation. We sought to test the following hypotheses: 1) maternal obesity is associated with altered HBC density and phenotype in the term placenta and 2) obesity-associated HBC changes are associated with altered placental lipid transport to the fetus. The impact of fetal sex was evaluated in all experiments.

METHODS

We quantified the density and morphology of CD163-and CD68-positive HBCs in placental villi in 34 full-term pregnancies undergoing cesarean delivery (N = 15, maternal BMI ≥30 kg/m2; N = 19, BMI <30 kg/m2). Antibody-positive cells in terminal villi were detected and cell size and circularity analyzed using a semi-automated method for thresholding of bright-field microscopy images (ImageJ). Placental expression of lipid transporter genes was quantified using RTqPCR, and cord plasma triglycerides (TGs) were profiled using modified Wahlefeld method. The impact of maternal obesity and fetal sex on HBC features, lipid transporters, and cord TGs were evaluated by two-way ANOVA. Spearman correlations of cord TGs, HBC metrics and gene expression levels were calculated.

RESULTS

Maternal obesity was associated with significantly increased density of HBCs, with male placentas most affected (fetal sex by maternal obesity interaction p = 0.04). CD163+ HBCs were larger and rounder in obesity-exposed male placentas. Sexually dimorphic expression of placental FATP4, FATP6, FABPPM, AMPKB1 and AMPKG and cord TGs was noted in maternal obesity, such that levels were higher in males and lower in females relative to sex-matched controls. Cord TGs were positively correlated with HBC density and FATP1 expression.

DISCUSSION

Maternal obesity is associated with sex-specific alterations in HBC density and placental lipid transporter expression, which may impact umbilical cord blood TG levels and offspring cardiometabolic programming.

Incidence of de novo stress urinary incontinence following minimally invasive sacrocolpopexy

INTRODUCTION AND HYPOTHESIS

The objective was to investigate the incidence and risk factors of postoperative de novo stress urinary incontinence (SUI) in stress-continent women following minimally invasive sacrocolpopexy without an anti-incontinence procedure.

METHODS

We completed a multicenter, retrospective cohort study of women undergoing laparoscopic sacrocolpopexy without concurrent anti-incontinence procedures from October 2006 through January 2021.

RESULTS

Of the 169 women who underwent minimally invasive sacrocolpopexy, 17.1% (n=30) developed de novo SUI, and 7.1% eventually underwent a midurethral sling placement. On logistic regression, BMI, preoperative urinary urgency, and history of transvaginal mesh repair were found to be significantly associated with and predictive of de novo SUI. When the concordance index (C-index) was calculated with the model published by Jelovsek et al. for women who developed de novo SUI within 12 months of the prolapse surgery, the current de novo SUI calculator was able to discriminate de novo SUI outcome (C-index = 0.71).

CONCLUSIONS

The incidence of de novo SUI after minimally invasive sacrocolpopexy without anti-incontinence procedure correlates directly with higher BMI, preoperative urinary urgency, and transvaginal mesh history for POP. Preoperative counseling for minimally invasive sacrocolpopexy should include discussing the risk of de novo SUI and preoperative factors that may increase this risk.

The impact of cryopreserved sperm on intrauterine insemination outcomes: is frozen as good as fresh?

Introduction

Frozen sperm utilization might negatively impact cycle outcomes in animals, implicating cryopreservation-induced sperm damage. However, in vitro fertilization and intrauterine insemination (IUI) in human studies are inconclusive.

Methods

This study is a retrospective review of 5,335 IUI [± ovarian stimulation (OS)] cycles from a large academic fertility center. Cycles were stratified based on the utilization of frozen (FROZEN, n = 1,871) instead of fresh ejaculated sperm (FRESH, n = 3,464). Main outcomes included human chorionic gonadotropin (HCG) positivity, clinical pregnancy (CP), and spontaneous abortion (SAB) rates. Secondary outcome was live birth (LB) rate. Odds ratios (OR) for all outcomes were calculated utilizing logistic regression and adjusted (adjOR) for maternal age, day-3 FSH, and OS regimen. Stratified analysis was performed based on OS subtype [gonadotropins; oral medications (OM): clomiphene citrate and letrozole; and unstimulated/natural]. Time to pregnancy and cumulative pregnancy rates were also calculated. Further subanalyses were performed limited to either the first cycle only or to the partner's sperm only, after excluding female factor infertility, and after stratification by female age (<30, 30-35, and >35 years old).

Results

Overall, HCG positivity and CP were lower in the FROZEN compared to the FRESH group (12.2% vs. 15.6%, p < 0.001; 9.4% vs. 13.0%, p < 0.001, respectively), which persisted only among OM cycles after stratification (9.9% vs. 14.2% HCG positivity, p = 0.030; 8.1% vs. 11.8% CP, p = 0.041). Among all cycles, adjOR (95% CI) for HCG positivity and CP were 0.75 (0.56-1.02) and 0.77 (0.57-1.03), respectively, ref: FRESH. In OM cycles, adjOR (95% CI) for HCG positivity [0.55 (0.30-0.99)] and CP [0.49 (0.25-0.95), ref.: FRESH] favored the FRESH group but showed no differences among gonadotropin and natural cycles. SAB odds did not differ between groups among OM and natural cycles but were lower in the FROZEN group among gonadotropin cycles [adjOR (95% CI): 0.13 (0.02-0.98), ref.: FRESH]. There were no differences in CP and SAB in the performed subanalyses (limited to first cycles or partner's sperm only, after excluding female factors, or after stratification according to female age). Nevertheless, time to conception was slightly longer in the FROZEN compared to the FRESH group (3.84 vs. 2.58 cycles, p < 0.001). No significant differences were present in LB and cumulative pregnancy results, other than in the subgroup of natural cycles, where higher LB odds [adjOR (95% CI): 1.08 (1.05-1.12)] and higher cumulative pregnancy rate (34% vs. 15%, p = 0.002) were noted in the FROZEN compared to the FRESH group.

Conclusion

Overall, clinical outcomes did not differ significantly between frozen and fresh sperm IUI cycles, although specific subgroups might benefit from fresh sperm utilization.

Provider confidence in counseling preconception, pregnant, and postpartum patients regarding COVID-19 vaccination: A cross-sectional survey study

Background and Aims

Healthcare provider counseling surrounding COVID-19 vaccine in pregnancy and lactation is essential to vaccination uptake in this population; however, provider knowledge and confidence are not well characterized. We aimed to assess knowledge and confidence in COVID-19 vaccine counseling among practitioners who provide care to pregnant persons and to describe factors associated with confidence in counseling.

Methods

A web-based anonymous survey was distributed via email to a cross-sectional convenience sample of Obstetrics and Gynecology, Primary Care, and Internal Medicine faculty at three hospitals in a single healthcare network in Massachusetts, United States. Individual demographics and institution-specific variables were included in the survey along with questions assessing both attitudes toward COVID-19 illness and confidence in counseling regarding the use of the vaccine in pregnancy.

Results

Almost all providers (151, 98.1%) reported that they received a COVID-19 vaccine, and most (111, 72.1%) reported that they believe the benefits of the vaccine in pregnancy outweigh the risks. Forty-one (26.6%) reported feeling very confident in counseling patients who primarily speak English about the evidence for messenger ribonucleic acid vaccination in pregnancy, and 36 (23%) reported feeling very confident in counseling patients who are not primarily English-speaking. Forty-three providers (28.1%) expressed strong confidence in their comfort talking to individuals with vaccine hesitancy based on historic and continued racism and systemic injustices. The sources that survey respondents most used to find information regarding COVID-19 vaccination in pregnancy were the Centers for Disease Control (112, 74.2%), hospital-specific resources (94, 62.3%), and the American College of Obstetricians and Gynecologists (82, 54.3%).

Conclusion

Ensuring that providers feel comfortable bridging the gap between their belief that the vaccine is beneficial for pregnant patients and their comfort with holding conversations with patients regarding vaccination is paramount to ensure equitable access to vaccines for pregnant patients.

Availability Versus Accessibility: Identifying COVID-19 Testing Deserts Across Massachusetts

Throughout the COVID-19 pandemic, communities of color have faced significantly higher rates of COVID-19 infection, as well as poor clinical outcomes. These differences are driven by long-standing structural inequities that prevent effective social distancing efforts and are further exacerbated by disparities in COVID-19 testing. Our study applied the concept of "COVID-19 testing deserts" to systematically identify gaps in testing resource allocation across Massachusetts in May 2020 and March 2021. Testing deserts were identified at the census tract level, using criteria developed by the Department of Agriculture for food deserts. Testing deserts occurred more frequently in segregated Hispanic, segregated Black, mixed minority, and integrated communities, as well as in neighborhoods with low vehicle access and in federally designated Medically Underserved Areas. Segregated communities were those in which more than 50 percent of the population self-identified as non-Hispanic White, Hispanic, non-Hispanic Black, or non-Hispanic Asian, respectively. Testing deserts were overrepresented in counties with high COVID-19 incidence rates, suggesting that testing accessibility is essential for prompt COVID-19 diagnosis and self-isolation.

External Validation of a Prediction Model for External Cephalic Version Success

External cephalic version (ECV) success correlates with numerous maternal and pregnancy factors. A prior study developed an ECV success prediction model based on body mass index, parity, placental location, and fetal presentation. We performed external validation of this model using a retrospective cohort of ECV procedures from a separate institution between July 2016 and December 2021. Four hundred thirty-four ECV procedures were performed, with a 44.4% success rate (95% CI 39.8-49.2%), which was similar to the derivation cohort (40.6%, 95% CI 37.7-43.5%, P=.16). There were significant differences in patients and practices between cohorts, including the rate of neuraxial anesthesia (83.5% derivation cohort vs 10.4% our cohort, P<.001). The area under the receiver operating characteristic curve (AUROC) was 0.70 (95% CI 0.65-0.75), which was similar to that in the derivation cohort (AUROC 0.67, 95% CI 0.63-0.70). These results suggest the published ECV prediction model's performance is generalizable outside the original study institution.

The impact of anti-Müllerian hormone on endometrial thickness in gonadotropin stimulation/intrauterine insemination cycles: is there an effect on pregnancy outcomes?

PURPOSE

To study the association, if any, between anti-Müllerian hormone (AMH) and pre-ovulatory endometrial thickness (ET) in gonadotropin/intrauterine insemination (IUI) cycles.

METHODS

This retrospective cohort study included a total of 964 patients undergoing 1926 gonadotropin/IUI cycles at an academic fertility center. Primary outcome measure was the association between serum AMH and measured ET on the day of and the day before human chorionic gonadotropin hormone (hCG) ovulation trigger. The effect of a model combining AMH and ET on early pregnancy outcomes was a secondary measure.

RESULTS

In 52.8% of cycles, ET was last assessed and recorded on the day of hCG administration, while in the remaining 47.2% on the day prior to trigger. In unadjusted regression models, AMH was weakly correlated with ET on hCG trigger day [bAMH (95%CI) = 0.032 (- 0.008, 0.070), p = 0.015]. When adjusting for potential confounders, the positive correlation became significant [0.051 (0.006, 0.102), p = 0.047]. Similar findings were observed when assessing the correlation between AMH and ET on the day prior to hCG trigger. ET was non-significantly associated with the odds of clinical pregnancy, when adjusting for potential confounders, except for when restricting the analysis to couples with idiopathic infertility [OR (95%CI), p-value: 0.787 (0.623, 0.993), 0.044].

CONCLUSION

Our findings support an effect of serum AMH on endometrial development in gonadotropin induced cycles, even when adjusting for the diagnosis of PCOS. ET was not associated with the odds of achieving a clinical pregnancy, except for couples with idiopathic infertility.

The Application of a Standard Risk Threshold for the Stratification of Maternal Morbidity among Population Subgroups

OBJECTIVE

 The aim of this study was to determine if a universally applied risk score threshold for severe maternal morbidity (SMM) resulted in different performance characteristics among subgroups of the population.

STUDY DESIGN

 This is a retrospective cohort study of deliveries that occurred between July 1, 2016, and June 30, 2020, in a single health system. We examined the performance of a validated comorbidity score to stratify SMM risk in our cohort. We considered the risk score that was associated with the highest decile of predicted risk as a "screen positive" for morbidity. We then used this same threshold to calculate the sensitivity and positive predictive value (PPV) of this "highest risk" designation among subgroups of the overall cohort based on the following characteristics: age, race/ethnicity, parity, gestational age, and planned mode of delivery.

RESULTS

 In the overall cohort of 53,982 women, the C-statistic was 0.755 (95% confidence interval [CI], 0.741-0.769) and calibration plot demonstrated that the risk score was well calibrated. The model performed less well in the following groups: non-White or Hispanic (C-statistic, 0.734; 95% CI, 0.712-0.755), nulliparas (C-statistic, 0.735; 95% CI, 0.716-0.754), term deliveries (C-statistic, 0.712; 95% CI, 0.694-0.729), and planned vaginal delivery (C-statistic, 0.728; 95% CI, 0.709-0.747). There were differences in the PPVs by gestational age (7.8% term and 29.7% preterm) and by planned mode of delivery (8.7% vaginal and 17.7% cesarean delivery). Sensitivities were lower in women who were <35 years (36.6%), non-White or Hispanic (40.7%), nulliparous (38.9%), and those having a planned vaginal delivery (40.9%) than their counterparts.

CONCLUSION

 The performance of a risk score for SMM can vary by population subgroups when using standard thresholds derived from the overall cohort. If applied without such considerations, such thresholds may be less likely to identify certain subgroups of the population that may be at increased risk of SMM.

KEY POINTS

· Predictive risk models are helpful at condensing complex information into an interpretable output.. · Model performance may vary among different population subgroups.. · Prediction models should be examined for their potential to exacerbate underlying disparities..

Pregnancy- and birth-related risk factors for the development of childhood celiac disease

AIM

To evaluate whether pregnancy and birth-related factors are associated with celiac disease (CD) in a large, United States (US)-based mother-child cohort.

METHODS

We analysed data gathering from the Massachusetts General Hospital Maternal Child Cohort (MMCC) of children born between 1998 and 2016. Data included the mode of delivery, maternal pregnancy and their offspring characteristics. We searched for CD cases by using diagnosis billing codes. Cox proportional hazard regression models were created to identify variables associated with CD.

RESULTS

We identified 44 539 mother-child pairs who had at least one encounter by 5 years old and identified 173 children (0.4%) with CD diagnosis; median age at the diagnosis was 6 years. Overall, the adjusted hazard ratio (aHR) of caesarean delivery for CD was 1.39 (95% CI: 0.99, 1.96, p = 0.06) when compared to children born vaginally. After stratifying for the presence of labour, children born by Caesarean delivery without labour had a higher risk of CD (aHR 1.56; 95%CI: 1.01, 2.41; p = 0.046) while infants born by Caesarean delivery with labour did not (aHR 1.26; 95% CI: 0.83, 1.93; p = 0.28).

CONCLUSION

Being born by Caesarean delivery without labour may be associated with an increased risk for CD in the US children.

Antenatal Steroid Exposure Among Term Newborns

This cross-sectional study evaluates the association between dissemination of the Antenatal Late Preterm Steroid trial and changes in steroid exposure among term newborns.

Trends in gestational age at delivery for intrahepatic cholestasis of pregnancy and adoption of society guidelines

BACKGROUND

Intrahepatic cholestasis of pregnancy is associated with a significant risk of stillbirth, which contributes to variation in clinical management. Recent Society for Maternal-Fetal Medicine guidance recommends delivery at 36 weeks of gestation for patients with serum bile acid levels of >100 μmol/L, consideration for delivery between 36 and 39 weeks of gestation stratified by bile acid level, and against preterm delivery for those with clinical features of cholestasis without bile acid elevation.

OBJECTIVE

This study aimed to investigate institutional practices before the publication of the new delivery timing recommendations to establish the maternal and neonatal effects of late preterm, early-term, and term deliveries in the setting of cholestasis.

STUDY DESIGN

This study examined maternal and neonatal outcomes of 441 patients affected by cholestasis delivering 484 neonates in a 4-hospital system over a 30-month period. Logistic and linear regression analyses were performed to assess neonatal outcomes concerning peak serum bile acid levels at various gestational ages controlling for maternal comorbidities, multiple pregnancies, and neonatal birthweight.

RESULTS

With the clinical flexibility afforded by the new guidelines, pregnancy prolongation to term may have been achieved in 91 patients (21%), and 286 patients (74%) with bile acid elevation could have delivered at a later gestational age. Preterm deliveries of patients with bile acid levels of >10 μmol/L were associated with higher rates of neonatal intensive care unit admission and adverse neonatal outcomes than early-term deliveries.

CONCLUSION

Study data suggested an opportunity for education and practice change to reflect current Society for Maternal-Fetal Medicine guidelines in efforts to reduce potential neonatal morbidities associated with late preterm deliveries among pregnancies affected by cholestasis.

Comparison of Natural Language Processing of Clinical Notes With a Validated Risk-Stratification Tool to Predict Severe Maternal Morbidity

IMPORTANCE

Risk-stratification tools are routinely used in obstetrics to assist care teams in assessing and communicating risk associated with delivery. Electronic health record data and machine learning methods may offer a novel opportunity to improve and automate risk assessment.

OBJECTIVE

To compare the predictive performance of natural language processing (NLP) of clinician documentation with that of a previously validated tool to identify individuals at high risk for maternal morbidity.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective diagnostic study was conducted at Brigham and Women's Hospital and Massachusetts General Hospital, Boston, Massachusetts, and included individuals admitted for delivery at the former institution from July 1, 2016, to February 29, 2020. A subset of these encounters (admissions from February to December 2018) was part of a previous prospective validation study of the Obstetric Comorbidity Index (OB-CMI), a comorbidity-weighted score to stratify risk of severe maternal morbidity (SMM).

EXPOSURES

Natural language processing of clinician documentation and OB-CMI scores.

MAIN OUTCOMES AND MEASURES

Natural language processing of clinician-authored admission notes was used to predict SMM in individuals delivering at the same institution but not included in the prospective OB-CMI study. The NLP model was then compared with the OB-CMI in the subset with a known OB-CMI score. Model discrimination between the 2 approaches was compared using the DeLong test. Sensitivity and positive predictive value for the identification of individuals at highest risk were prioritized as the characteristics of interest.

RESULTS

This study included 19 794 individuals; 4034 (20.4%) were included in the original prospective validation study of the OB-CMI (testing set), and the remaining 15 760 (79.6%) composed the training set. Mean (SD) age was 32.3 (5.2) years in the testing cohort and 32.2 (5.2) years in the training cohort. A total of 115 individuals in the testing cohort (2.9%) and 468 in the training cohort (3.0%) experienced SMM. The NLP model was built from a pruned vocabulary of 2783 unique words that occurred within the 15 760 admission notes from individuals in the training set. The area under the receiver operating characteristic curve of the NLP-based model for the prediction of SMM was 0.76 (95% CI, 0.72-0.81) and was comparable with that of the OB-CMI model (0.74; 95% CI, 0.70-0.79) in the testing set (P = .53). Sensitivity (NLP, 28.7%; OB-CMI, 24.4%) and positive predictive value (NLP, 19.4%; OB-CMI, 17.6%) were comparable between the NLP and OB-CMI high-risk designations for the prediction of SMM.

CONCLUSIONS AND RELEVANCE

In this study, the NLP method and a validated risk-stratification tool had a similar ability to identify patients at high risk of SMM. Future prospective research is needed to validate the NLP approach in clinical practice and determine whether it could augment or replace tools requiring manual user input.

US Incidence of Late-Preterm Steroid Use and Associated Neonatal Respiratory Morbidity After Publication of the Antenatal Late Preterm Steroids Trial, 2015-2017

IMPORTANCE

The Antenatal Late Preterm Steroids (ALPS) trial demonstrated a 20% reduction in the risk of respiratory complications in neonates at risk for a late-preterm birth who were exposed to antenatal corticosteroids compared with those who were not.

OBJECTIVE

To assess whether new evidence of steroid administration for neonatal respiratory benefit in the late-preterm period is associated with changes in obstetric practice and the use of assisted ventilation for the neonate after delivery.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study of US births from February 1, 2015, to October 31, 2017, as ascertained from US natality data, included live-born, singleton neonates born between 34 and 36 completed weeks of gestation to people without pregestational diabetes. An interrupted time series analysis using Poisson regression models was conducted. Data were analyzed from July 11, 2022, to November 9, 2022.

EXPOSURES

Public dissemination of the ALPS trial results, which occurred during a 9-month period from February 1, 2016 (first published online), to October 31, 2016 (time of the last major professional society's guideline update in the months after the trial's publication).

MAIN OUTCOMES AND MEASURES

Steroid use, any assisted ventilation use, and assisted ventilation use for more than 6 hours immediately after the dissemination period.

RESULTS

A total of 707 862 births were included, divided among the 12-month predissemination period (n = 250 643), dissemination period (n = 195 736), and 12-month postdissemination period (n = 261 493). Most births were at 36 weeks of gestation (53.9% in the predissemination and postdissemination period; P = .10). Small but significant differences were found between the predissemination and postdissemination period cohorts: there were more individuals 35 years or older (19.5% vs 17.9%), fewer White individuals (67.8% vs 69.8%), and more publicly insured individuals (50.5% vs 50.1%) in the postdissemination period compared with the predissemination period, respectively (P < .001 for all). Compared with what rates were expected based on the predissemination trends, the adjusted rate of steroid use increased from 5.0% to 11.7% (adjusted incidence rate ratio [IRR], 2.34; 95% CI, 2.13-2.57), and assisted ventilation use decreased from 8.9% to 8.2% (adjusted IRR, 0.91; 95% CI, 0.85-0.98) after the dissemination period. No change was observed in assisted ventilation use for more than 6 hours (adjusted IRR, 0.98; 95% CI, 0.87-1.10).

CONCLUSIONS AND RELEVANCE

These findings suggest that there was an immediate change in practice of administering antenatal steroids and a reduction in neonatal morbidity among late-preterm births associated with the dissemination of the ALPS trial, suggesting that this evidence may be translating into a reduction in immediate respiratory morbidity outside the context of a clinical trial.

Placental Expression of ACE2 and TMPRSS2 in Maternal Severe Acute Respiratory Syndrome Coronavirus 2 Infection: Are Placental Defenses Mediated by Fetal Sex?

BACKGROUND

Expression of angiotensin-converting enzyme 2 (ACE2) and type II transmembrane serine protease (TMPRSS2), host molecules required for viral entry, may underlie sex differences in vulnerability to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We investigated whether placental ACE2 and TMPRSS2 expression vary by fetal sex in the presence of maternal SARS-CoV-2 infection.

METHODS

Placental ACE2 and TMPRSS2 expression was quantified by quantitative reverse transcription polymerase chain reaction (RT-PCR) and by Western blot in 68 pregnant women (38 SARS-CoV-2 positive, 30 SARS-CoV-2 negative) delivering at Mass General Brigham from April to June 2020. The impact of fetal sex and maternal SARS-CoV-2 exposure on ACE2 and TMPRSS2 was analyzed by 2-way analysis of variance (ANOVA).

RESULTS

Maternal SARS-CoV-2 infection impacted placental TMPRSS2 expression in a sexually dimorphic fashion (2-way ANOVA interaction, P = .002). We observed no impact of fetal sex or maternal SARS-CoV-2 status on ACE2. TMPRSS2 expression was significantly correlated with ACE2 expression in males (Spearman ρ = 0.54, P = .02) but not females (ρ = 0.23, P = .34) exposed to maternal SARS-CoV-2.

CONCLUSIONS

Sex differences in placental TMPRSS2 but not ACE2 were observed in the setting of maternal SARS-CoV-2 infection, which may have implications for offspring vulnerability to placental infection.

Derivation and external validation of risk stratification models for severe maternal morbidity using prenatal encounter diagnosis codes

OBJECTIVE

We sought to develop a prediction model using prenatal diagnosis codes that could help clinicians objectively stratify a women's risk for delivery-related morbidity.

STUDY DESIGN

We performed a prospective cohort study of women delivering at a single academic medical center between 2016 and 2019. Diagnosis codes from outpatient encounters were extracted from the electronic health record. Standard and common machine-learning methods for variable selection were compared. The performance characteristics from the selected model in the training data set-a LASSO model with a lambda that minimized the Bayes information criteria-were compared in a testing and external validation set.

RESULTS

The model identified a group of women, those in the highest decile of predicted risk, who were at a two to threefold increased risk of maternal morbidity.

CONCLUSION

As EHR data becomes more ubiquitous, other data types generated from the prenatal period may improve the model's performance.

Association between morbidity among term newborns and low-risk caesarean delivery rates

OBJECTIVE

To examine the association between county-level caesarean delivery (CD) rates among women at low risk and morbidity among term newborns.

DESIGN

Cross-sectional study.

SETTING

Population-based study of US county-level birth data from 2015 to 2017.

POPULATION

Nulliparous women with term, singleton, vertex-presenting infants (NTSV) at low risk for morbidity.

METHODS

The primary exposure was county-level CD rates.

MAIN OUTCOME MEASURES

The outcome was morbidity among the low-risk NTSV cohort, categorised as severe (5-minute Apgar score of ≤3, assisted ventilation for ≥6 hours, severe neurologic injury or seizure, transfer or death) or moderate (5-minute Apgar score of <7 but >3, administration of antibiotics or assisted ventilation at delivery). We used linear regression models to determine the association between county NTSV CD and neonatal morbidity rates with cluster robust standard errors.

RESULTS

The analysis included data from 2 753 522 births in 952 counties from all 48 states. The mean NTSV CD rate was 23.6% (standard deviation 4.8%). The median severe and moderate neonatal morbidity rates were 15.2 (interquartile range, IQR 9.4-23.6) and 52.5 (IQR 33.4-75.7) per 1000 births, respectively. In the unadjusted analysis using the risk-adjusted exposure and outcome, every percentage point increase in the CD rate of a county was associated with 0.6 (95% CI -0.9, -0.3) and 2.3 fewer (95% CI -3.4, -1.1) cases of severe and moderate neonatal morbidity per 1000 live births. After adjustment for other county factors, the relationships remained significant. These findings were tested in multiple sensitivity analyses.

CONCLUSIONS

Lower county-level NTSV CD rates were associated with a small increase in morbidity among term newborns in the USA.

TWEETABLE ABSTRACT

Lower county-level caesarean delivery rates were associated with an increase in morbidity among term newborns in the USA.

Association between hospital-level cesarean delivery rates and severe maternal morbidity and unexpected newborn complications

BACKGROUND

Although there are many indications for a cesarean delivery, the "optimal" cesarean delivery rate is unknown. Neonatal and maternal morbidity have largely not been considered in the generation of hospital-level cesarean delivery rate targets.

OBJECTIVE

We sought to examine if the widely adopted and reported markers of maternal and neonatal morbidity were associated with hospital cesarean delivery rates to provide context for potential comparison and consideration for defining cesarean delivery rate targets. We hypothesized that hospitals with higher cesarean delivery rates would have increased rates of severe maternal morbidity, though we were less certain of the associations of the cesarean delivery rates with unexpected newborn complications.

STUDY DESIGN

This is a cross-sectional, ecological study using data from the 2016 Nationwide Readmission Database of hospitals with at least 100 deliveries per year. The exposure of interest was hospital cesarean delivery rate. The outcomes were (1) severe maternal morbidity with and without transfusion-in accordance with the Centers for Disease Control and Prevention's definition, and (2) neonatal morbidity-defined using The Joint Commission's Perinatal Quality metric of moderate and severe unexpected newborn complications among term, singleton, and nonanomalous neonates. Before assuming a single linear relationship to model the associations between morbidity and cesarean delivery rates, the Joinpoint Regression Analysis program was used to examine for potential splines in the relationships with both severe maternal morbidity (with and without transfusion) and severe and moderate unexpected newborn complications. Poisson regression model was then used to determine the association between morbidity and cesarean delivery rates.

RESULTS

The analysis included 831,111 deliveries from 621 hospitals. The mean cesarean delivery rate was 30.5%. The median severe maternal morbidity rate was 1.40 per 100 deliveries (interquartile range, 0.71-2.21 per 1000 deliveries). Excluding transfusion, the median severe maternal morbidity rate was 0.47 per 100 deliveries (interquartile range, 0.22-0.73 per 100 deliveries). The median rate of severe and moderate unexpected newborn complications was 1.01 per 100 low-risk newborns (interquartile range, 0.64-1.69 per 100 low-risk newborns) and 1.79 per 1000 low-risk newborns (interquartile range, 0.94-2.93 per 100 low-risk newborns), respectively. In the unadjusted analysis, every percentage point increase in a hospital's cesarean delivery rate was associated with a 3.4% (95% confidence interval, 2.3%-4.4%) and a 2.3% (95% confidence interval, 1.0%-3.5%) increase in severe maternal morbidity including and excluding transfusion, respectively. After adjustment for the case mix and hospital factors, only the relationship with severe maternal morbidity including transfusion remained significant: 3.3% (95% confidence interval, 1.7%-4.9%) increase in severe maternal morbidity per 1 percentage point increase in the cesarean delivery rate. There was no observed association between cesarean delivery rates and unexpected newborn complications CONCLUSION: Severe maternal morbidity and unexpected newborn complications occur in fewer than 5 in 100 births. Findings from this analysis of hospitals with cesarean delivery rates ranging from 6.8%-56.3% suggest that those with lower cesarean delivery rates have lower severe maternal morbidity (which includes transfusion) and similar unexpected newborn complications compared with hospitals with higher cesarean delivery rates. This work may provide a helpful context to providers, hospitals, and policymakers who are measuring and reporting outcomes. Regarding neonatal morbidity in particular, the Joint Commission manual notes that the unexpected newborn complication metric was specifically designed to be compared against maternal-focused metrics such as cesarean delivery rates. More work is needed to define and identify appropriate measures of maternal and neonatal morbidity for these types of comparisons.

Response to ovulation induction treatments in women with polycystic ovary syndrome as a function of serum anti-Müllerian hormone levels

PURPOSE

To assess whether anti-Müllerian hormone (AMH) can predict response to ovulation induction (OI) with clomiphene citrate (CC), letrozole (LET), or follicle-stimulating hormone (FSH) in women with polycystic ovary syndrome (PCOS) undergoing OI/intrauterine inseminations (IUI).

METHODS

A total of 738 OI/IUI cycles from 242 patients at an academic center were stratified in three groups by medication: CC (n = 295), LET (n = 180), and FSH (n = 263), in a retrospective fashion. Ovarian response to treatment (RT, development of at least one dominant follicle) was assessed using mixed effects logistic regression models.

RESULTS

Overall, RT cycles had lower AMH levels compared to no-RT cycles (p < 0.001). This finding persisted when analysis was limited to oral agents but attenuated in FSH cycles. For CC and LET cycles, the predicted probability (PProb) for RT decreased as AMH levels increased (PProb (95%CI): 97% (93-100), 79% (70-88), and 75% (61-89); 85% (78-93), 75% (67-83), and 73% (63-86) for AMH pct.: ≤ 25th, ≥ 50th, and ≥ 75th, for CC and LET, respectively)). However, RT was noted in 98.5% of FSH/IUI cycles regardless of AMH. For CC cycles, those with AMH ≥ 75th pct. had lower odds for RT over cycles with AMH < 75th pct. (OR 0.2, 95%CI 0.04-0.8, p = 0.02). Similarly, lower odds for RT were observed in LET cycles with AMH ≥ 75th pct. (0.6, 0.3-1.4, p = 0.25).

CONCLUSION

In PCOS, increasing serum AMH levels are associated with lower probability of RT to oral agents. Our findings constitute a valuable tool for the clinician when counseling PCOS patients and designing a personalized ovulation induction treatment strategy.

Pretreatment antimüllerian hormone levels and outcomes of ovarian stimulation with gonadotropins/intrauterine insemination cycles

OBJECTIVE

To evaluate the association, if any, between serum antimüllerian hormone (AMH) levels and probability of clinical pregnancy and spontaneous abortion (SAB) in the infertility setting.

DESIGN

Retrospective cohort study.

SETTING

Academic fertility center.

PATIENT(S)

A total of 1,861 gonadotropin stimulation/intrauterine insemination cycles stratified by AMH levels into 3 groups: Low, <25th percentile (<0.7 ng/mL); Middle, ≥25th and <75th percentile (0.7-4.4 ng/mL); and High, ≥75th percentile (≥4.5 ng/mL).

INTERVENTION(S)

Intrauterine insemination after stimulation with gonadotropins.

MAIN OUTCOME MEASURE(S)

Cumulative probability of clinical pregnancy over a maximum of 3 and/or 6 cycles and SAB incidence risk rate (IRR). The Kaplan-Meier failure function (log rank test), Cox proportional hazards models, and multilevel mixed-effects Poisson regression models were performed to compare outcomes among the AMH groups.

RESULT(S)

Overall, in both unadjusted and adjusted models, the probability of achieving a clinical pregnancy was higher in the Middle and High AMH groups compared with that in the Low AMH group, both over 3 (hazard ratios [95% confidence interval], 1.55 [1.05-2.29] and 1.85 [1.22-2.81], respectively) and 6 (1.71 [1.17-2.48] and 2.12 [1.42-3.16], respectively) cycles. In the unadjusted models, the SAB IRR was higher among the Low AMH group (IRR [95% confidence interval], 2.17 (1.11-4.24]), with the relationship persisting after adjusting for age (1.83 [0.93-3.60]). When the SAB IRR were calculated separately for the subpopulations with and without polycystic ovary syndrome, a similar relationship was noted among the latter in the unadjusted (1.94 [0.97-3.88]) and adjusted (1.74 [0.86-3.49]) analyses.

CONCLUSION(S)

In women undergoing gonadotropin stimulation/intrauterine insemination, AMH appears to affect the probability of achieving a clinical pregnancy. A possible negative impact, independent of age, on the risk of SAB was also suggested.

Compromised SARS-CoV-2-specific placental antibody transfer

SARS-CoV-2 infection causes more severe disease in pregnant women compared to age-matched non-pregnant women. Whether maternal infection causes changes in the transfer of immunity to infants remains unclear. Maternal infections have previously been associated with compromised placental antibody transfer, but the mechanism underlying this compromised transfer is not established. Here, we used systems serology to characterize the Fc profile of influenza-, pertussis-, and SARS-CoV-2-specific antibodies transferred across the placenta. Influenza- and pertussis-specific antibodies were actively transferred. However, SARS-CoV-2-specific antibody transfer was significantly reduced compared to influenza- and pertussis-specific antibodies, and cord titers and functional activity were lower than in maternal plasma. This effect was only observed in third-trimester infection. SARS-CoV-2-specific transfer was linked to altered SARS-CoV-2-antibody glycosylation profiles and was partially rescued by infection-induced increases in IgG and increased FCGR3A placental expression. These results point to unexpected compensatory mechanisms to boost immunity in neonates, providing insights for maternal vaccine design.

Assessment of Maternal and Neonatal SARS-CoV-2 Viral Load, Transplacental Antibody Transfer, and Placental Pathology in Pregnancies During the COVID-19 Pandemic

Importance

Biological data are lacking with respect to risk of vertical transmission and mechanisms of fetoplacental protection in maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Objective

To quantify SARS-CoV-2 viral load in maternal and neonatal biofluids, transplacental passage of anti-SARS-CoV-2 antibody, and incidence of fetoplacental infection.

Design, Setting, and Participants

This cohort study was conducted among pregnant women presenting for care at 3 tertiary care centers in Boston, Massachusetts. Women with reverse transcription-polymerase chain reaction (RT-PCR) results positive for SARS-CoV-2 were recruited from April 2 to June 13, 2020, and follow-up occurred through July 10, 2020. Contemporaneous participants without SARS-CoV-2 infection were enrolled as a convenience sample from pregnant women with RT-PCR results negative for SARS-CoV-2.

Exposures

SARS-CoV-2 infection in pregnancy, defined by nasopharyngeal swab RT-PCR.

Main Outcomes and Measures

The main outcomes were SARS-CoV-2 viral load in maternal plasma or respiratory fluids and umbilical cord plasma, quantification of anti-SARS-CoV-2 antibodies in maternal and cord plasma, and presence of SARS-CoV-2 RNA in the placenta.

Results

Among 127 pregnant women enrolled, 64 with RT-PCR results positive for SARS-CoV-2 (mean [SD] age, 31.6 [5.6] years) and 63 with RT-PCR results negative for SARS-CoV-2 (mean [SD] age, 33.9 [5.4] years) provided samples for analysis. Of women with SARS-CoV-2 infection, 23 (36%) were asymptomatic, 22 (34%) had mild disease, 7 (11%) had moderate disease, 10 (16%) had severe disease, and 2 (3%) had critical disease. In viral load analyses among 107 women, there was no detectable viremia in maternal or cord blood and no evidence of vertical transmission. Among 77 neonates tested in whom SARS-CoV-2 antibodies were quantified in cord blood, 1 had detectable immunoglobuilin M to nucleocapsid. Among 88 placentas tested, SARS-CoV-2 RNA was not detected in any. In antibody analyses among 37 women with SARS-CoV-2 infection, anti-receptor binding domain immunoglobin G was detected in 24 women (65%) and anti-nucleocapsid was detected in 26 women (70%). Mother-to-neonate transfer of anti-SARS-CoV-2 antibodies was significantly lower than transfer of anti-influenza hemagglutinin A antibodies (mean [SD] cord-to-maternal ratio: anti-receptor binding domain immunoglobin G, 0.72 [0.57]; anti-nucleocapsid, 0.74 [0.44]; anti-influenza, 1.44 [0.80]; P < .001). Nonoverlapping placental expression of SARS-CoV-2 receptors angiotensin-converting enzyme 2 and transmembrane serine protease 2 was noted.

Conclusions and Relevance

In this cohort study, there was no evidence of placental infection or definitive vertical transmission of SARS-CoV-2. Transplacental transfer of anti-SARS-CoV-2 antibodies was inefficient. Lack of viremia and reduced coexpression and colocalization of placental angiotensin-converting enzyme 2 and transmembrane serine protease 2 may serve as protective mechanisms against vertical transmission.