Reductions in stillbirths and preterm birth in COVID-19-vaccinated women: a multicenter cohort study of vaccination uptake and perinatal outcomes.

BACKGROUND: COVID-19 infection in pregnancy is associated with a higher risk of progression to severe disease, but vaccine uptake by pregnant women is hindered by persistent safety concerns. COVID-19 vaccination in pregnancy has been shown to reduce stillbirth, but its relationship with preterm birth is uncertain. OBJECTIVE: This study aimed to measure the rate of COVID-19 vaccine uptake among women giving birth in Melbourne, Australia, and to compare perinatal outcomes by vaccination status. STUDY DESIGN: This was a retrospective multicenter cohort study conducted after the June 2021 government recommendations for messenger RNA COVID-19 vaccination during pregnancy. Routinely collected data from all 12 public maternity hospitals in Melbourne were extracted on births at ≥20 weeks' gestation from July 1, 2021 to March 31, 2022. Maternal sociodemographic characteristics were analyzed from the total birth cohort. Perinatal outcomes were compared between vaccinated and unvaccinated women for whom weeks 20 to 43 of gestation fell entirely within the 9-month data collection period. The primary outcomes were the rates of stillbirth and preterm birth (spontaneous and iatrogenic) in singleton pregnancies of at least 24 weeks' gestation, after exclusion of congenital anomalies. Secondary perinatal outcomes included the rate of congenital anomalies among infants born at ≥20 weeks' gestation and birthweight ≤third centile and newborn intensive care unit admissions among infants born without congenital anomalies at ≥24 weeks' gestation. We calculated the adjusted odds ratio of perinatal outcomes among vaccinated vs unvaccinated women using inverse propensity score-weighting regression adjustment with multiple covariates; P<.05 was considered statistically significant. RESULTS: Births from 32,536 women were analyzed: 17,365 (53.4%) were vaccinated and 15,171 (47.6%) were unvaccinated. Vaccinated women were more likely to be older, nulliparous, nonsmoking, not requiring an interpreter, of higher socioeconomic status, and vaccinated against pertussis and influenza. Vaccination status also varied by region of birth. Vaccinated women had a significantly lower rate of stillbirth compared with unvaccinated women (0.2% vs 0.8%; adjusted odds ratio, 0.18; 95% confidence interval, 0.09-0.37; P<.001). Vaccination was associated with a significant reduction in total preterm births at <37 weeks (5.1% vs 9.2%; adjusted odds ratio, 0.60; 95% confidence interval, 0.51-0.71; P<.001), spontaneous preterm birth (2.4% vs 4.0%; adjusted odds ratio, 0.73; 95% confidence interval, 0.56-0.96; P=.02), and iatrogenic preterm birth (2.7% vs 5.2%; adjusted odds ratio, 0.52; 95% confidence interval, 0.41-0.65; P<.001). Infants born to vaccinated mothers also had lower rates of admission to the neonatal intensive care unit. There was no significant increase in the rate of congenital anomalies or birthweight ≤3rd centile in vaccinated women. Vaccinated women were significantly less likely to have an infant with a major congenital anomaly compared with the unvaccinated group (2.4% vs 3.0%; adjusted odds ratio, 0.72; 95% confidence interval, 0.56-0.94; P=.02). This finding remained significant even when the analysis was restricted to women vaccinated before 20 weeks' gestation. CONCLUSION: COVID-19 vaccination during pregnancy was associated with a reduction in stillbirth and preterm birth, and not associated with any adverse impact on fetal growth or development. Vaccine coverage was substantially influenced by known social determinants of health.

Reduction in spontaneous and iatrogenic preterm births in twin pregnancies during COVID-19 lockdown in Melbourne, Australia: a multicenter cohort study.

BACKGROUND: Melbourne, Australia, recorded one of the longest and most stringent pandemic lockdowns in 2020, which was associated with an increase in preterm stillbirths among singleton pregnancies. Twin pregnancies may be particularly susceptible to the impacts of pandemic disruptions to maternity care due to their higher background risk of adverse perinatal outcomes. METHODS: Multicenter retrospective cohort study of all twin pregnancies birthing in public maternity hospitals in Melbourne. Multivariable log-binomial regression models were used to compare perinatal outcomes between a pre-pandemic group to women in whom weeks 20+0 to 40+0 of gestation occurred entirely during one of two lockdown-exposure periods: exposure 1 from 22 March 2020 to 21 March 2021 and exposure 2 from 22 March 2021 to 27 March 2022. RESULTS: Total preterm births < 37 weeks were significantly lower in exposure 1 compared with the pre-pandemic period (63.1% vs 68.3%; adjusted risk ratio 0.92 95% CI 0.87-0.98, p = 0.01). This was mainly driven by fewer spontaneous preterm births (18.9% vs 20.3%; adjusted risk ratio 0.95 95% CI 0.90-0.99, p = 0.04). There were also lower rates of preterm birth < 34 weeks (19.9% vs 23.0%, adjusted risk ratio 0.93 95% CI 0.89-0.98 p = 0.01) and total iatrogenic births for fetal compromise (13.4% vs 20.4%; adjusted risk ratio 0.94 95% CI 0.89-0.98, p = 0.01). There were fewer special care nursery admissions (38.5% vs 43.4%; adjusted risk ratio 0.91 95% CI 0.87-0.95, p < 0.001) but no significant changes in stillbirth (1.5% vs 1.6%; adjusted risk ratio 1.00 95% CI 0.99-1.01, p = 0.82). Compared with the pre-pandemic period, there were more preterm births < 28 weeks and neonatal intensive care unit admissions in exposure 2. CONCLUSIONS: Melbourne's first lockdown-exposure period was associated with lower preterm births in twins without significant differences in adverse newborn outcomes. Our findings provide insights into the influences on preterm birth and the optimal timing of delivery for twins.

Increase in preterm stillbirths in association with reduction in iatrogenic preterm births during COVID-19 lockdown in Australia: a multicenter cohort study.

BACKGROUND: The COVID-19 pandemic has been associated with a worsening of perinatal outcomes in many regions around the world. Melbourne, Australia, had one of the longest and most stringent lockdowns worldwide in 2020 while recording only rare instances of COVID-19 infection in pregnant women. OBJECTIVE: This study aimed to compare the stillbirth and preterm birth rates in women who were exposed or unexposed to lockdown restrictions during pregnancy. STUDY DESIGN: This was a retrospective, multicenter cohort study of perinatal outcomes in Melbourne before and during the COVID-19 lockdown. The lockdown period was defined as the period from March 23, 2020 to March 14, 2021. Routinely-collected maternity data on singleton pregnancies ≥24 weeks gestation without congenital anomalies were obtained from all the 12 public hospitals in Melbourne. We defined the lockdown-exposed cohort as those women for whom weeks 20 to 40 of gestation occurred during the lockdown and the unexposed control group as women from the corresponding calendar periods 12 and 24 months before. The main outcome measures were stillbirth, preterm birth, fetal growth restriction (birthweight < third centile), and iatrogenic preterm birth for fetal compromise. We performed multivariable logistic regression analysis to compare the odds of stillbirth, preterm birth, fetal growth restriction, and iatrogenic preterm birth for fetal compromise, adjusting for multiple covariates. RESULTS: There were 24,817 births in the exposed group and 50,017 births in the control group. There was a significantly higher risk of preterm stillbirth in the exposed group than the control group (0.26% vs 0.18%; adjusted odds ratio, 1.49; 95% confidence interval, 1.08-2.05; P=.015). There was also a significant reduction in the preterm birth of live infants <37 weeks (5.68% vs 6.07%; adjusted odds ratio, 0.93; 95% confidence interval, 0.87-0.99; P=.02), which was largely mediated by a significant reduction in iatrogenic preterm birth (3.01% vs 3.27%; adjusted odds ratio, 0.91; 95% confidence interval, 0.83-0.99; P=.03), including iatrogenic preterm birth for fetal compromise (1.25% vs 1.51%; adjusted odds ratio, 0.82; 95% confidence interval, 0.71-0.93; P=.003). There were also significant reductions in special care nursery admissions during lockdown (11.53% vs 12.51%; adjusted odds ratio, 0.90; 95% confidence interval, 0.86-0.95; P<.0001). There was a trend to fewer spontaneous preterm births <37 weeks in the exposed group of a similar magnitude to that reported in other countries (2.69% vs 2.82%; adjusted odds ratio, 0.95; 95% confidence interval, 0.87-1.05; P=.32). CONCLUSION: Lockdown restrictions in Melbourne, Australia were associated with a significant reduction in iatrogenic preterm birth for fetal compromise and a significant increase in preterm stillbirths. This raises concerns that pandemic conditions in 2020 may have led to a failure to identify and appropriately care for pregnant women at an increased risk of antepartum stillbirth. Further research is required to understand the relationship between these 2 findings and to inform our ongoing responses to the pandemic.

The addition of fetal scalp blood lactate measurement as an adjunct to cardiotocography to reduce caesarean sections during labour: The Flamingo randomised controlled trial.

BACKGROUND: Fetal scalp blood sampling for lactate measurement (FBSLM) is sometimes used to assist in identification of the need for expedited birth in the presence of an abnormal cardiotocograph (CTG). However, there is no randomised controlled trial evidence to support this. AIM: To determine whether adding FBSLM reduces the risk of birth by emergency caesarean section in labours complicated by an abnormal CTG, compared with CTG without FBS. MATERIAL AND METHODS: Labouring women at a tertiary maternity hospital in Melbourne, Australia with a singleton, cephalic presentation, at ≥37 weeks gestation with an abnormal CTG pattern were randomised to the intervention (n = 61), with intermittent FBSLM in addition to CTG monitoring, or control (CTG without FBS, n = 62). The primary outcome was rate of birth by caesarean section. Secondary outcomes included overall operative birth and fetal and neonatal safety endpoints. TRIAL REGISTRATION: ACTRN12611000172909. RESULTS: The smaller than anticipated sample was unable to demonstrate an effect from adding FBSLM to CTG monitoring on birth by caesarean section vs monitoring by CTG without FBS (25/61 and 28/62 respectively, P = 0.64, risk ratio 0.91, 95% confidence intervals 0.60-1.36). One newborn infant in the CTG group met the criteria for the composite neonatal outcome of death or serious outcome, neonatal encephalopathy, five-minute Apgar score < 4, neonatal resuscitation, admission to neonatal intensive care unit for 96 h or more. CONCLUSION: We were unable to provide robust evidence of the effectiveness of FBSLM to improve the specificity of the CTG in the assessment of fetal wellbeing.

Cervical length surveillance for predicting spontaneous preterm birth in women with uterine anomalies: A cohort study.

INTRODUCTION: Uterine anomalies occur in an estimated 5% of women and have been shown to confer a higher risk of spontaneous preterm birth (SPTB). A sonographically short cervix (<25 mm) is a risk indicator for SPTB, although its predictive utility has been little studied in this specific high-risk population. We aimed to assess the pregnancy outcomes and predictive ability of short cervix in a cohort of women with uterine anomalies attending a high-risk antenatal clinic. MATERIAL AND METHODS: This historical cohort study assessed all pregnancies in women with congenital uterine anomalies referred to the Preterm labor Clinic at the Royal Women's Hospital, Melbourne, Australia, between 2004 and 2013. Logistic and linear regressions and receiver-operator curves were used to examine associations between cervical length and preterm birth. RESULTS: SPTB (<37 weeks' gestation) occurred in 23% of the 86 pregnancies (n = 20); rates by subgroup were: unicornuate uterus 60% (n = 3/5), uterus didelphys 40% (n = 6/15), bicornuate uterus 18% (n = 9/51), septate uterus 13% (n = 2/15). Preterm prelabor rupture of membranes occurred in 55% of spontaneous preterm births and was not independently associated with the presence of cervical cerclage or ureaplasma urealyticum. Short cervical length was associated with SPTB in women with septate uterus. Short cervix at 24 weeks (not at 16 or 20 weeks) was moderately predictive of SPTB < 34 weeks. CONCLUSIONS: Women with uterine anomalies are at increased risk of spontaneous preterm birth, particularly those with unicornuate uterus or uterus didelphys, but cervical surveillance did not identify these cases. Short cervix may be associated with SPTB in women with septate uterus. Preterm prelabor rupture of membranes occurred in 55% of SPTB. More research is required into etiology to help determine appropriate monitoring and treatment.

Assessment of Placental Cortisol Pathway Gene Expression in Term Pregnant Women with Anxiety.

INTRODUCTION: The aim of this study was to expand on this field of work by examining, within a cohort of pregnant women with diagnosed clinical anxiety, the mRNA expression of a panel of genes associated with the cortisol pathway and comparing them to controls. METHODS: Placental samples were obtained from 24 pregnant women, 12 with a diagnosed anxiety disorder and 12 with no psychiatric history, within 30 min of delivery. Differential expression analysis of 85 genes known to be involved in glucocorticoid synthesis, metabolism or signalling was conducted for the: (1) full sample, (2) those at term without labour (5 cases, 7 controls) and (3) those at term with labour (7 cases, 5 controls). Correlation analyses between gene expression and measures of anxiety and depressive symptom severity were also conducted. RESULTS: No robust difference in placental gene expression between pregnant women with and without anxiety disorder was found nor did we detect robust differences by labour status. However, correlational analyses putatively showed a decrease in PER1 expression was associated with an increase in anxiety symptom severity, explaining up to 32% of the variance in anxiety symptom severity. DISCUSSION: Overall, the strongest correlation was found between a decrease in placental PER1 expression and increased anxiety scores. Labour status was found to have a profound effect on mRNA expression. The placental samples obtained from women following labour produced greater numbers of significant differences in mRNA species expression suggesting that in long-standing anxiety the placenta may respond differently under conditions of chronic stress.

Subclinical hypothyroidism during pregnancy: the Melbourne public hospitals consensus.

BACKGROUND: Interest in potential adverse outcomes associated with maternal subclinical hypothyroidism (normal free T4, elevated thyroid-stimulating hormone (TSH)) has increased significantly over recent years. In turn, the frequency of maternal thyroid function testing has risen, despite universal thyroid function screening not being recommended, leading to a marked increase in referrals to obstetric endocrinology clinics. In 2017 the American Thyroid Association revised their diagnostic and management guidelines. Although welcome, these new guidelines contain recommendations that may cause confusion in clinical practice. AIM: To ensure uniform practice in the diagnosis and management of subclinical hypothyroidism in pregnancy across all Melbourne public hospitals. METHODS: Endocrinology and obstetric representatives from all Melbourne public hospital networks reviewed the 2017 American Thyroid Association guidelines and other relevant literature to develop a consensus for diagnosing and treating subclinical hypothyroidism during pregnancy in Melbourne. The consensus guidelines were then referred to the Endocrine Society of Australia for comment and endorsement. RESULTS: Consensus was achieved and the guidelines were endorsed by the Council of the Endocrine Society of Australia. Trimester and assay-specific TSH reference intervals derived from healthy local populations should be used, where available. When unavailable, a TSH cut-off of 4 mU/L (replacing the previously recommended 2.5 mU/L) should be used to initiate treatment, irrespective of thyroid auto-antibody status. The recommended starting dose of levothyroxine is 50 µg daily, with a therapeutic TSH target of 0.1-2.5 mU/L. Levothyroxine should generally be ceased after delivery, with some exceptions. Hospitals will ensure smooth transfer of care back to the woman's general practitioner with clear documentation of pregnancy thyroid management and a recommended plan for follow-up. CONCLUSION: Fewer women will be classified as having subclinical hypothyroidism during pregnancy, which is likely to lead to reductions in emotional stress, hospital visits, repeated blood tests and financial costs. Uniform clinical practice will occur across Melbourne.

Clinical Application of Quantitative Foetal Fibronectin for the Prediction of Preterm Birth in Symptomatic Women.

AIM: To evaluate the clinical application of the new Hologic quantitative foetal fibronectin (qfFN) bedside test for the prediction of spontaneous preterm birth (sPTB) in patients with symptoms suggestive of spontaneous threatened preterm labour (sPTL). METHODS: A prospective observational study with 154 pregnant women presenting signs and symptoms of sPTL was conducted. These women were subjected to a qfFN test between 22 and 35 weeks of gestation For each cut-off threshold, the ability to predict sPTB at within 14 days of conducting the test and <37 weeks was assessed by calculating the positive predictive value (PPV), negative predictive value (NPV), likelihood ratios, odds ratios, sensitivity, and specificity. RESULTS: For the outcome of delivery within 14 days of the test, qfFN <10 ng/mL had a 100% NPV and >200 ng/mL produced a 50.0% PPV; thus, qfFN added enhanced discrimination between high- and low-risk patients. The overall rate of sPTB (<37) was 13.3% (16/120), which increased progressively with increasing levels of fFN, with rates of 9.8% (8/81), 11.5% (3/26), 14.2% (1/7), 50% (3/6) within the 4 categories (fFN 0-9, 10-49, 50-200, 200+) respectively. CONCLUSIONS: The use of the qfFN testing in symptomatic patients allowed for more accurate identification of women at risk of sPTB and thus more directed management.

Changes in myometrial expression of progesterone receptor membrane components 1 and 2 are associated with human parturition at term.

While the exact mechanism of human parturition remains unknown, functional progesterone withdrawal is believed to play a key regulatory role. Progesterone receptor membrane components 1 and 2 (PGRMC1, PGRMC2) are putative progesterone receptors and the aim of this project was to investigate their expression in human myometrium. Human term myometrium was obtained from the lower uterine segment incision in women undergoing elective (not-in-labour, NIL; n=11) and emergency Caesarean sections (in-labour, IL; n=10), following written consent. PGRMC1 and 2 expression was quantified using real-time reverse transcription polymerase chain reaction and western blot. Subcellular localisation was performed by immunohistochemistry and immunofluorescence. There was a significant decrease in PGRMC1 mRNA (P=0.0317) and protein expression (P=0.0151) in IL myometrium, compared with NIL myometrium. PGRMC2 mRNA expression (P=0.0151) was also decreased in IL myometrium, compared with NIL myometrium. Immunostaining studies confirmed the presence of PGRMC1 and 2 in smooth-muscle cells. Expression was perinuclear in NIL myometrium and more generalised and cytoplasmic in IL myometrium. The decrease in PGRMC1 expression and the translocation away from a perinuclear location for both PGRMC1 and 2 could contribute to a functional progesterone withdrawal that may ultimately initiate parturition.