Objective: This study tests the clinical hypothesis that FNAIT secondary to anti-HPA-1a results in smaller newborns, and the corollary hypothesis that antenatal management of FNAIT in HPA-1a-incompatible pregnancies increases birthweight by reducing the effects of anti-HPA-1a. Design: FNAIT-affected siblings, one untreated and one treated for FNAIT, were paired for the purpose of comparing their birthweights. Birthweights of FNAIT-affected and -unaffected pups in a mouse model of HPA-1a-specific-FNAIT were also analyzed. Setting: New York Presbyterian-Weill Cornell Medical Center, New York, NY; Versiti Blood Research Institute, Milwaukee, WI. Population: 270 FNAIT-affected newborns from a randomized clinical trial; responders to a NAITbabies.org; and pups in a mouse model of HPA-1a-specific-FNAIT were evaluated. Methods: Birthweight percentiles of untreated FNAIT-affected neonates were compared to those of published controls and treated FNAIT-affected siblings using one-sample, two-tailed t-tests. Body weights of FNAIT-affected and -unaffected pups in a mouse model of HPA-1a-specific-FNAIT were analyzed similarly. Main Outcome Measures: The difference in birthweight percentile between untreated and treated FNAIT-affected siblings was analyzed. Results: Untreated siblings were not small compared to normal controls. However, treated siblings in both cohorts had significantly higher birthweight percentiles compared to their untreated, affected sibling. FNAIT-affected neonatal pups had lower body weights than FNAIT-unaffected pups. Conclusions: The effect of treatment, especially high dose IVIG believed to “block” FcRn and lower maternal anti-HPA-1a levels, to increase birthweights suggests maternal anti-HPA-1a reduces birthweights. We believe this is mediated by anti-HPA-1a binding to placental syncytiotrophoblasts, resulting in placental inflammation.

Objective: To evaluate the association between certified nurse midwife (CNM) annual delivery workload and short-term, adverse maternal and neonatal outcomes occurring in vaginal deliveries. Design: A retrospective cohort study Setting: A single tertiary academic center. Population: All single, live vertex term vaginal deliveries between 2006 and 2018 were included Methods: deliveries were categorized into two groups based on the CNM median annual volume of deliveries during the study duration. The “high-volume” and “low-volume” groups included deliveries above and below the median annual delivery volume, respectively as a dichotomous variable. Further analyses were performed for the annual volume by deciles. Main outcomes measures: Short term maternal and neonatal outcomes were compared between “high-volume” and “low-volume” groups and between deciles. Results: During the study period 140,856 deliveries met the study criteria. The median annual deliveries of a single CNM was 152 [114-195]. Maternal and labor characteristics were comparable between the groups. Maternal outcomes were not significantly associated with the CNM’s annual workload. However, neonates delivered by CNMs with “low” annual volume had higher a higher rate of neonatal jaundice (aOR 1.07, 95% CI [1.00-1.14]) and mechanical ventilation (aOR 1.32, 95% CI [1.05-1.66). Conclusion: Adverse perinatal outcomes are only mildly affected by CNM’s annual volume after controlling for the CNM, parturient and neonate’s characteristics. Funding: This study was not funded by any organization.