Objective: To determine SARS-CoV-2 seroprevalence in a UK pregnancy cohort and assess associations with demographic factors and vaccination timing. Design: Observational cohort study. Setting: UK inner-city maternity centre. Sample: 960 pregnant women attending nuchal scans from July 2020-January 2022. Methods: Blood samples were tested for IgG antibodies against SARS-CoV-2 nucleocapsid (N) and spike (S) proteins. Self-reported demographics, vaccination status and previous Covid-19 infection were extracted from health records. Multivariable regression models determined factors associated with seroprevalence and antibody titers. Main outcome measures: IgG N- and S-protein antibody titers. Results: 196/960 (20.4%) women were SARS-CoV-2 seropositive from previous infection. Of these, 70 (35.7%) self-reported previous infection. Amongst unvaccinated women, black women were most likely to be SARS-CoV-2 seropositive (aRR 1.88 [95% CI, 1.35-2.61], P < 0.001). Women from black and mixed ethnic backgrounds were least likely to have a history of vaccination with seropositivity to S-protein (aRR 0.58 [95% CI, 0.40-0.84], P = 0.004 and aRR 0.56 [95% CI, 0.34-0.92], P = 0.021 respectively). Double vaccinated, previously infected women had higher IgG S-protein antibody titers than unvaccinated, previously infected women (mean difference: 4.76, 95% CI = [2.65, 6.86], P < 0.001). Vaccination timing before vs during pregnancy did not significantly affect IgG S antibody titers (F(1, 77) = [0.07], P = 0.785). Conclusions: This inner-city pregnancy cohort demonstrates high rates of asymptomatic SARS-CoV-2 infection with women of black ethnicity having higher infection risk and lower vaccine uptake. SARS-CoV-2 antibody titers were highest among double vaccinated, previously infected women.

Objective: To evaluate whether a particular group of women with intrahepatic cholestasis of pregnancy would benefit from treatment with ursodeoxycholic acid. Design: Secondary analysis of the PITCHES trial (ISRCTN91918806). Setting: United Kingdom. Population or Sample: Women with intrahepatic cholestasis of pregnancy. Methods: Subgroup analyses were performed to determine whether baseline bile acid concentrations or baseline itch scores moderated a woman’s response to treatment with ursodeoxycholic acid. Main Outcome Measures: Bile acid concentration and itch score. Results: In women with baseline bile acid concentrations less than 40 μmol/L, treatment with UDCA resulted in increased post-randomisation bile acid concentrations (geometric mean ratio 1.19, 95% CI 1.99 to 1.41, p = 0.048). A test of interaction showed no significance (p = 0.647). A small, clinically insignificant difference was seen in itch response in women with a high baseline itch score (–6.0 mm, 95% CI –11.80 to –0.21, p = 0.042), with a test of interaction not showing significance (p = 0.640). Further subgroup analyses showed no significance. Across all women there was a weak relationship between bile acid concentrations and itch severity. Conclusions: There was no subgroup of women with intrahepatic cholestasis of pregnancy in whom a beneficial effect of treatment with ursodeoxycholic acid on bile acid concentration or itch score could be identified. This confirms that its routine use in women with this condition for improvement of bile acid concentration or itch score should be reconsidered. Funding: NIHR Efficacy and Mechanism Evaluation Programme 12/164/16. Keywords: Cholestasis, Pregnancy, Ursodeoxycholic acid, Perinatal, Stillbirth.

Objective: to establish a prognostic model informing optimal timing of delivery in women with late preterm preeclampsia. Design: development and validation of a prognostic model Setting: prospective cohort study, nested in the PHOENIX trial, in 36 maternity units across England and Wales. Population: women with late preterm pre-eclampsia (34+0-36+6 weeks’ gestation) Methods: prospective recruitment of women in whom blood samples for Placental Growth Factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) testing was obtained, alongside clinical data, for use within the ‘Prediction of complications in early-onset pre-eclampsia’ (PREP)-S model. Candidate variables were compared using standard methods (sensitivity, specificity, Receiver Operator Curve areas). Estimated probability of early delivery from PREP-S was compared to actual event rates by calibration. Main Outcome Measures: clinically indicated need for delivery for pre-eclampsia within seven days. Results: PlGF testing had high sensitivity (97.9%) for delivery within seven days, but negative predictive value was only 71.4%, with low specificity (8.4%). The area under the curve for PREP-S was 0.64 (standard error (SE) 0.03), for PlGF was 0.60 (SE 0.03), and 0.65 (0.03), and 0.64 (0.03) for PREP-S in combination with PlGF and sFlt-1:PlGF, respectively. Conclusions: PlGF-based testing does not add to clinical assessment to determine need for delivery in late preterm pre-eclampsia. Existing models developed in women with early onset pre-eclampsia to predict complications cannot be used to predict clinically indicated need for delivery in women with late preterm pre-eclampsia. Funding: NIHR HTA Monitoring Add on Studies Programme (reference 15/59/06). Keywords: placental growth factor, preeclampsia, prognosis