Perinatal outcomes after admission with COVID-19 in pregnancy: a UK national cohort study

There are few population-based studies of sufficient size and follow-up duration to have reliably assessed perinatal outcomes for pregnant women hospitalised with SARS-CoV-2 infection. The United Kingdom Obstetric Surveillance System (UKOSS) covers all 194 consultant-led UK maternity units and included all pregnant women admitted to hospital with an ongoing SARS-CoV-2 infection. Here we show that in this large national cohort comprising two years’ active surveillance over four SARS-CoV-2 variant periods and with near complete follow-up of pregnancy outcomes for 16,627 included women, severe perinatal outcomes were more common in women with moderate to severe COVID-19, during the delta dominant period and among unvaccinated women. We provide strong evidence to recommend continuous surveillance of pregnancy outcomes in future pandemics and to continue to recommend SARS-CoV-2 vaccination in pregnancy to protect both mothers and babies

Perinatal outcomes after admission with COVID-19 in pregnancy:a UK national cohort study

There are few population-based studies of sufficient size and follow-up duration to have reliably assessed perinatal outcomes for pregnant women hospitalised with SARS-CoV-2 infection. The United Kingdom Obstetric Surveillance System (UKOSS) covers all 194 consultant-led UK maternity units and included all pregnant women admitted to hospital with an ongoing SARS-CoV-2 infection. Here we show that in this large national cohort comprising two years’ active surveillance over four SARS-CoV-2 variant periods and with near complete follow-up of pregnancy outcomes for 16,627 included women, severe perinatal outcomes were more common in women with moderate to severe COVID-19, during the delta dominant period and among unvaccinated women. We provide strong evidence to recommend continuous surveillance of pregnancy outcomes in future pandemics and to continue to recommend SARS-CoV-2 vaccination in pregnancy to protect both mothers and babies

Early suppression policies protected pregnant women from COVID-19 in 2020: A population-based surveillance from the Nordic countries

Introduction The Coronavirus 2019 Disease (COVID-19) pandemic reached the Nordic countries in March 2020. Public health interventions to limit viral transmission varied across different countries both in timing and in magnitude. Interventions indicated by an Oxford Stringency Index ≥50 were implemented early (March 13–17, 2020) in Denmark, Finland, Norway and Iceland, and on March 26, 2020 in Sweden. The aim of the current study was to assess the incidence of COVID-19-related admissions of pregnant women in the Nordic countries in relation to the different national public health strategies during the first year of the pandemic. Material and methods This is a meta-analysis of population-based cohort studies in the five Nordic countries with national or regional surveillance in the Nordic Obstetric Surveillance System (NOSS) collaboration: national data from Denmark, Finland, Iceland and Norway, and regional data covering 31% of births in Sweden. The source population consisted of women giving birth in the included areas March 1–December 31, 2020. Pregnant women with a positive SARS-CoV-2 PCR test ≤14 days before hospital admission were included, and admissions were stratified as either COVID-19-related or non-COVID (other obstetric healthcare). Information about public health policies was retrieved retrospectively. Results In total, 392 382 maternities were considered. Of these, 600 women were diagnosed with SARS-CoV-2 infection and 137 (22.8%) were admitted for COVID-19 symptoms. The pooled incidence of COVID-19 admissions per 1000 maternities was 0.5 (95% confidence interval [CI] 0.2 to 1.2, I2 = 77.6, tau2 = 0.68, P = 0.0), ranging from no admissions in Iceland to 1.9 admissions in the Swedish regions. Interventions to restrict viral transmission were less stringent in Sweden than in the other Nordic countries. Conclusions There was a clear variation in pregnant women's risk of COVID-19 admission across countries with similar healthcare systems but different public health interventions to limit viral transmission. The meta-analysis indicates that early suppression policies protected pregnant women from severe COVID-19 disease prior to the availability of individual protection with vaccines

Obstetric care in Norway - the role of institution availability and place of delivery for maternal and perinatal outcomes. Population-based retrospective cohort studies

Background: Obstetric care in midwife-led institutions may be more cost-effective and reduce the number of interventions during labour. On the other hand, large obstetric institutions may offer more technologically advanced and specialised care. Knowledge of how availability of and access to different types of obstetric institutions impact maternal and perinatal clinical outcomes in a high-income context is lacking. Aims: The aim of this thesis was to assess availability of and access to obstetric institutions in Norway during recent decades and to assess perinatal and maternal clinical outcomes by travel time to institution and place of birth. The first study assessed changes in travel time on a population level, the risk of unplanned birth outside institution over time, as well as the risk of maternal morbidity. The second study aimed to assess the association of mother’s travel time to an obstetric institution and place of birth with peripartum perinatal mortality. The aim of the third study was to assess risk of eclampsia and HELLP syndrome by the mother’s travel time to an obstetric institution and place of delivery. Material and methods: The studies were conducted using population-based data from Norway. The primary data source was the Medical Birth Registry of Norway (MBRN), and we included births from 1979 to 2009. The mother’s unique national identification number was used to link births in the MBRN to her registered address. Statistics Norway provided geographic coordinates linked to National Registry addresses for two ecological cross-sectional studies and two cohort analyses. We also used the mother’s unique identification number to link births to their mother in a sibling-structure to assess clinical outcomes in subsequent pregnancies. Obstetric institutions were categorised by function and annual number of births. Availability of and access to obstetric institutions was based on the woman’s travel time to the nearest obstetric institution. Travel time was estimated using geographic information systems software combined with the Norwegian digital road database. Population proportions and risks were assessed using cross-tables. Logistic regression and generalized linear models were used to calculate odds ratios and relative risks with 95% confidence intervals and to adjust for confounders. Travel time ≤ 1 hour was used as reference for all travel time analyses. Multilevel regression models were used to account for clustering by several births to the same mother and by births in the same institution. Sibling structures with the mother as the observation unit were used to assess outcomes in successive pregnancies. Results: In the first study, we found a 10% increase in the proportion of women of reproductive age living outside the 1-hour travel zone to all obstetric institutions and to Emergency Obstetric and Newborn Care (EmONC) institutions from 2000 to 2010. On a national level, the risk of unplanned birth outside institution doubled from 1979- 83 to 2004-09 and the differences between counties increased. The risk of maternal morbidity increased by 40% from 2000 to 2009 on a national level, with increasing regional differences. The second study showed that unplanned birth outside institution was associated with higher risk of peripartum perinatal death (death during delivery or within the first 24 hours). Women with travel time exceeding one hour to any obstetric institution had higher risk of unplanned birth outside institution compared to women with less than 1 hour travel time. On a population level, 2 % of peripartum perinatal deaths could be attributed to unplanned birth outside institution. In the third study, we found that nulliparous women who had to travel more than one hour to any obstetric institutions had a 50 % higher risk of eclampsia or HELLPsyndrome. These complications occurred in all categories of obstetric institutions. Women with risk factors such as preeclampsia or previous preeclampsia delivered in the larger EmONC institutions. Deliveries prior to 35 gestational weeks were also referred to the largest EmONC institutions. Women with previous preeclampsia had a higher risk of recurrence, but the majority of parous women with eclampsia or HELLP did not have previous preeclampsia. Conclusion: Access to obstetric institutions and skilled birth attendance play an important role to reduce the risk of adverse clinical maternal and fetal outcomes. In planning or evaluating changes in the obstetric healthcare structure, associated changes in the distribution of benefits and burdens should be considered. Further work must aim at assessing risk of a wider range of maternal complications as well as neonatal morbidity and mortality

Availability and access in modern obstetric care: a retrospective population-based study

Objective: To assess the availability of obstetric institutions, the risk of unplanned delivery outside an institution and maternal morbidity in a national setting in which the number of institutions declined from 95 to 51 during 30 years. Design: Retrospective population-based, three cohorts and two cross-sectional analyses. Setting: Census data, Statistics Norway. The Medical Birth Registry of Norway from 1979 to 2009. Population: Women (15–49 years), 2000 (n=1 050 269) and 2010 (n=1 127 665). Women who delivered during the period 1979–2009 (n=1 807 714). Methods: Geographic Information Systems software for travel zone calculations. Cross-table and multiple logistic regression analysis of change over time and regional differences. World Health Organization Emergency Obstetric and Newborn Care (EmOC) indicators. Main outcome measures: Proportion of women living outside the 1-hour travel zone to obstetric institutions. Risk of unplanned delivery outside obstetric institutions. Maternal morbidity. Results: The proportion of women living outside the 1-hour zone for all obstetric institutions increased from 7.9% to 8.8% from 2000 to 2010 (relative risk, 1.1; 95% confidence interval, 1.11– 1.12), and for emergency obstetric care from 11.0% to 12.1% (relative risk, 1.1; 95% confidence interval, 1.09–1.11). The risk of unplanned delivery outside institutions increased from 0.4% in 1979–83 to 0.7% in 2004–09 (adjusted odds ratio, 2.0; 95% confidence interval, 1.9–2.2). Maternal morbidity increased from 1.7% in 2000 to 2.2% in 2009 (adjusted odds ratio, 1.4; 95% confidence interval, 1.2–1.5) and the regional differences increased. Conclusions: The availability of and access to obstetric institutions was reduced and we did not observe the expected decrease in maternal morbidity following the centralisation

Increased risk of peripartum perinatal mortality in unplanned births outside an institution: a retrospective population-based study

Background: Births in midwife-led institutions may reduce the frequency of medical interventions and provide cost-effective care, while larger institutions offer medically and technically advanced obstetric care. Unplanned births outside an institution and intrapartum stillbirths have frequently been excluded in previous studies on adverse outcomes by place of birth. Objective: The objective of the study was to assess peripartum mortality by place of birth and travel time to obstetric institutions, with the hypothesis that centralization reduces institution availability but improves mortality. Study Design: This was a national population-based retrospective cohort study of all births in Norway from 1999 to 2009 (n = 648,555) using data from the Medical Birth Registry of Norway and Statistics Norway and including births from 22 gestational weeks or birthweight ≥500 g. Main exposures were travel time to the nearest obstetric institution and place of birth. The main clinical outcome was peripartum mortality, defined as death during birth or within 24 hours. Intrauterine fetal deaths prior to start of labor were excluded from the primary outcome. Results: A total of 1586 peripartum deaths were identified (2.5 per 1000 births). Unplanned birth outside an institution had a 3 times higher mortality (8.4 per 1000) than institutional births (2.4 per 1000), relative risk, 3.5 (95% confidence interval, 2.5–4.9) and contributed 2% (95% confidence interval, 1.2–3.0%) of the peripartum mortality at the population level. The risk of unplanned birth outside an institution increased from 0.5% to 3.3% and 4.5% with travel time 2 hours, respectively. In obstetric institutions the mortality rate at term ranged from 0.7 per 1000 to 0.9 per 1000. Comparable mortality rates in different obstetric institutions indicated well-functioning routines for referral. Conclusion: Unplanned birth outside an institution was associated with increased peripartum mortality and with long travel time to obstetric institutions. Structural determinants have an important impact on perinatal health in high-income countries and also for low-risk births. The results show the importance of skilled birth attendance and warrant attention from clinicians and policy makers to negative consequences of reduced access to institutions

Pregnancy and risk of COVID-19: a Norwegian registry-linkage study

Objective: To compare the risk of acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and contact with specialist healthcare services for coronavirus disease 2019 (COVID-19) between pregnant and non-pregnant women. Population or sample: All women ages 15–45 living in Norway on 1 March 2020 (n = 1 033 699). Methods: We linked information from the national birth, patient, communicable diseases and education databases using unique national identifiers. Main outcome measure: We estimated hazard ratios (HR) among pregnant compared to non-pregnant women of having a positive test for SARS-CoV-2, a diagnosis of COVID-19 in specialist healthcare, or hospitalisation with COVID-19 using Cox regression. Multivariable analyses adjusted for age, marital status, education, income, country of birth and underlying medical conditions. Results: Pregnant women were not more likely to be tested for or to a have a positive SARS-CoV-2 test (adjusted HR 0.99; 95% CI 0.92–1.07). Pregnant women had higher risk of hospitalisation with COVID-19 (HR 4.70, 95% CI 3.51–6.30) and any type of specialist care for COVID-19 (HR 3.46, 95% CI 2.89–4.14). Pregnant women born outside Scandinavia were less likely to be tested, and at higher risk of a positive test (HR 2.37, 95% CI 2.51–8.87). Compared with pregnant Scandinavian-born women, pregnant women with minority background had a higher risk of hospitalisation with COVID-19 (HR 4.72, 95% CI 2.51–8.87). Conclusion: Pregnant women were not more likely to be infected with SARS-CoV-2. Still, pregnant women with COVID-19, especially those born outside of Scandinavia, were more likely to be hospitalised