Relationship between viral load, infection-to-delivery interval and mother-to-child transfer of anti-SARS-CoV-2 antibodies.

OBJECTIVE: To investigate the association of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load and infection-to-delivery interval with maternal and cord serum concentrations of anti-SARS-CoV-2 immunoglobulin G (IgG) antibodies and transplacental transfer ratio in pregnant women with active or recovered SARS-CoV-2 infection. METHODS: This was a prospective case series of consecutive pregnant women with laboratory-confirmed SARS-CoV-2 infection between 27 March 2020 and 24 January 2021. We collected information regarding deep throat saliva or nasopharyngeal swab (NPS) reverse transcription polymerase chain reaction (RT-PCR) test results, serial cycle threshold (Ct) values at and after diagnosis, demographic, clinical and outcome data, and neonatal NPS RT-PCR results. Qualitative and quantitative analysis of IgG and immunoglobulin M (IgM) antibodies against SARS-CoV-2 was performed in maternal and cord blood serum samples obtained at delivery. Correlation of maternal Ct values, infection-to-delivery interval, infection duration and viral load area under the curve (AUC) with gestational age (GA) at diagnosis, maternal and cord serum IgG concentrations and transplacental transfer ratio of IgG were evaluated using Pearson's correlation. RESULTS: Twenty pregnant women who consented to participate and who had delivered their babies by 31 January 2021 were included in the study, comprising 14 who had recovered from coronavirus disease 2019 (COVID-19) and six with active infection at delivery. The median GA at clinical manifestation was 32.7 (range, 11.9-39.4) weeks. The median infection-to-delivery interval and infection duration were 41.5 (range, 2-187) days and 10.0 (range, 1-48) days, respectively. The median GA at delivery was 39.1 (range, 32.4-40.7) weeks and the median seroconversion interval was 14 (range, 1-19) days. Of 13 neonates born to seropositive mothers with recovered infection at delivery, 12 tested positive for anti-SARS-CoV-2 IgG. All neonatal NPS samples were negative for SARS-CoV-2 and all cord sera tested negative for IgM. The median transplacental transfer ratio of IgG was 1.3 (interquartile range, 0.9-1.6). There was a negative correlation between infection-to-delivery interval and anti-SARS-CoV-2 IgG concentrations in maternal (r = -0.6693, P = 0.0087) and cord (r = -0.6554, P = 0.0068) serum and a positive correlation between IgG concentration in maternal serum and viral load AUC (r = 0.5109, P = 0.0310). A negative correlation was observed between transfer ratio and viral load AUC (r = -0.4757, P = 0.0409). CONCLUSIONS: In pregnant women who have recovered from COVID-19, anti-SARS-CoV-2 IgG concentrations at delivery increased with increasing viral load during infection and decreased with increasing infection-to-delivery interval. The median transplacental transfer ratio of IgG was 1.3 and it decreased with increasing viral load during infection. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Comparison of carbetocin and oxytocin infusions in reducing the requirement for additional uterotonics or procedures in women at increased risk of postpartum haemorrhage after Caesarean section.

INTRODUCTION: Postpartum haemorrhage is a major cause of maternal mortality and morbidity, commonly due to uterine atony. Prophylactic oxytocin use during Caesarean section is recommended; patients with a high risk of postpartum haemorrhage may require additional uterotonics or procedures. Carbetocin is a long-acting analogue of oxytocin which has shown beneficial results, compared with oxytocin. This study compared the requirement for additional uterotonics or procedures between at-risk women who underwent carbetocin infusion and those who underwent oxytocin infusion. METHODS: This retrospective cohort study included women at increased risk of postpartum haemorrhage after Caesarean section for various indications in a public hospital. Women who received carbetocin infusion and women who received oxytocin infusion were compared, stratified by Caesarean section timing (elective or emergency). The primary outcome was the requirement for additional uterotonic agents or procedures. Secondary outcomes included total blood loss, operating time, rate of postpartum haemorrhage, need for blood transfusion, and need for hysterectomy. RESULTS: Of 1236 women included in the study, 752 received oxytocin first and 484 received carbetocin first. The two groups had comparable blood loss, operating time, rate of postpartum haemorrhage, requirement for additional uterotonics or procedures, need for blood transfusion, and need for hysterectomy. There was a reduction in the requirement for additional uterotonics or procedures, and in the rate of postpartum haemorrhage for women with major placenta praevia or with multiple pregnancies, following receipt of carbetocin first. CONCLUSION: Compared with oxytocin, carbetocin can reduce the requirement for additional uterotonics or procedures in selected high-risk patient groups.