Adverse perinatal outcomes in 665,244 term and post-term deliveries-a Norwegian population-based study

Individual and familial factors associated with mRNA COVID-19 vaccine uptake in pregnancy: A large-scale registry-based linkage study

The association between maternal COVID-19 vaccination in pregnancy and factors such as high risk for severe COVID-19, pre-existing asthma, prior adverse reproductive history, or paternal COVID-19 vaccination during pregnancy, remains unclear. The aim of this study is two-fold: (i) to describe uptake of COVID-19 vaccine during pregnancy by maternal risk for severe COVID-19 and asthma, and (ii) to comprehensively examine individual and familial factors associated with vaccine uptake during pregnancy in Norway. Based on nation-wide registry-linkage data in Norway, we included 101,659 deliveries with gestational length ≥12 weeks, in 2021-2022. Our outcome measure was uptake of at least one dose of mRNA COVID-19 vaccine during pregnancy, using a narrow (first ever dose) and broad (any dose) definition. We fit univariate and multivariate modified Poisson regression models, clustered by county of residency and adjusted for calendar time, to estimate risk ratios (RR) with 95 % Confidence Intervals (CIs). Gestational uptake of any COVID-19 vaccine dose increased from <1 % before mid Aug-2021, to 38.8 % in the rest of 2021, and 48.9 % in 2022. Only 28.8 % and 33.9 % pregnant individuals with high risk for severe COVID-19 or asthma, respectively, received at least one COVID-19 vaccine dose. Paternal COVID-19 vaccination was strongly associated with greater vaccine uptake by pregnant individuals (adjusted RR: 7.2, 95 % CI: 6.8-7.5). Maternal SARS-CoV-2 infection pre-pregnancy (adjusted RR: 0.31, 95 % CI: 0.26, 0.37), familial and individual migrant status were associated with a considerable decreased likelihood of vaccine uptake in pregnancy. History of miscarriage or pregnancy with congenital anomaly were not associated with vaccine uptake. Despite rising COVID-19 vaccine rates in pregnancy, uptake remained low for high-risk individuals. Paternal vaccination, pre-pregnancy infection, migration status, and maternal citizenship were strongly associated with prenatal vaccine uptake. This knowledge can inform tailoring of future vaccination campaigns.

Adverse obstetric outcomes in cases of meconium-stained amniotic fluid complicated with intrapartum fever

PURPOSE

Meconium-stained amniotic fluid (MSAF) often signifies colonization of the amniotic sac by microorganisms. This study investigated additional adverse obstetric outcomes associated with MSAF in deliveries complicated by maternal intrapartum fever (IF).

METHODS

This retrospective study included all singleton pregnancies from 2014 to 2020, with intrapartum maternal fever ≥ 38 °C during a trial of labor. In accordance with departmental protocol, all patients received intravenous antibiotic therapy consisting of ampicillin and gentamicin in the absence of allergies to these medications. Subsequent antibiotic therapy was adjusted based on the culture results. Antibiotic treatment was discontinued postpartum after 48 h without fever. Swab cultures were obtained immediately postpartum from both the maternal and fetal sides of the placenta. Maternal and fetal outcomes, along with positive placental cultures, were compared between participants with MSAF&IF and those with clear amniotic fluid &IF (control group).

RESULTS

In comparison to the control group (n = 1089), the MSAF&IF group (n = 264) exhibited significantly higher rates of cesarean delivery (CD) (p = 0.001), CD due to non-reassuring fetal heart rate (p = 0.001), and cord pH ≤ 7.1 (p = 0.004). Positive swab cultures from the placental maternal and fetal sides were more prevalent among the MSAF&IF group (23.1% vs. 17.6%, p = 0.041 and 29.2% vs. 22.9%, p = 0.032, respectively). Placental cultures yielding gastrointestinal pathogens and extended spectrum beta-lactamase were notably more common in the MSAF&IF group compared to controls (p = 0.023). However, there was no significant difference between groups regarding the rate of group B streptococcus positive placental cultures.

CONCLUSIONS

Women experiencing IF and MSAF during labor face an elevated risk of CD compared to those with IF alone. The presence of MSAF heightens the risk of positive placental cultures, particularly with gastrointestinal and extended spectrum beta-lactamase pathogens.

Comorbidity in Congenital Hypothyroidism-A Nationwide, Population-based Cohort Study

CONTEXT

Patients with congenital hypothyroidism (CH) are affected more often than the general population by other chronic diseases and neurological difficulties.

OBJECTIVE

The aim of this nationwide population-based register study was to investigate the incidence of congenital malformations, comorbidities, and the use of prescribed drugs in patients with primary CH.

METHODS

The study cohort and matched controls were identified from national population-based registers in Finland. All diagnoses from birth until the end of 2018 were collected from the Care Register, and subject-specific prescription drug purchases were identified from The Prescription Register from birth until the end of 2017.

RESULTS

Diagnoses of neonatal and chronic diseases were collected for 438 full-term patients and 835 controls (median follow-up time 11.6 years; range, 0-23 years). Newborns with CH were more often found to have neonatal jaundice (11.2% and 2.0%; P < .001), hypoglycemia (8.9% and 2.8%; P < .001), metabolic acidemia (3.2% and 1.1%; P = .007), and respiratory distress (3.9% and 1.3%; P < .003) as compared to their matched controls.Congenital malformations were diagnosed in 66 of 438 (15.1%) CH patients and in 62 of 835 (7.4%) controls (P < .001). The most commonly affected extrathyroidal systems were the circulatory and musculoskeletal systems. The cumulative incidence of hearing loss and specific developmental disorders was higher among CH patients than controls. The use of antidepressant and antipsychotic drugs was similar in CH patients and their controls.

CONCLUSION

CH patients have more neonatal morbidity and congenital malformations than their matched controls. The cumulative incidence of neurological disorders is higher in CH patients. However, our results do not support the existence of severe psychiatric comorbidity.

Trends in Term Intrapartum Stillbirth in Norway

Importance

Fetal death during labor at term is a complication that is rarely studied in high-income countries. There is a need for large population-based studies to examine the rate of term intrapartum stillbirth in high-income countries and the factors associated with its occurrence.

Objective

To evaluate trends in term intrapartum stillbirth over time and to investigate the association between the trends and term intrapartum stillbirth risk factors from 1999 to 2018 in Norway.

Design, Setting, and Participants

This cohort study used data from the Medical Birth Registry of Norway from 1999 to 2018 to examine rates of term intrapartum stillbirth and risk factors associated with this event. A population of 1 021 268 term singleton pregnancies without congenital anomalies or antepartum stillbirths was included in analyses, which were performed from September 2022 to February 2023.

Exposure

The main exposure variable was time, which was divided into four 5-year periods: 1999 to 2003, 2004 to 2008, 2009 to 2013, and 2014 to 2018.

Main Outcomes and Measures

The primary study outcome was term intrapartum stillbirth. Risk ratios were calculated, and multivariable logistic regression analyses were conducted to identify factors associated with secular trends of term intrapartum stillbirth.

Results

The study population consisted of 1 021 268 term singleton births (maternal mean [SD] age, 29.72 [5.01] years; mean [SD] gestational age, 39.69 [1.27] weeks). During the study period, there were 95 term intrapartum stillbirths (0.09 per 1000 births). Maternal age, the proportion of individuals born in a country other than Norway, and the prevalence of gestational diabetes, labor induction, operative vaginal delivery, and previous cesarean delivery increased over the course of the study period. Conversely, the prevalence of infants large for gestational age, hypertensive disorder in pregnancy, and spontaneous vaginal delivery and the proportion of individuals who smoked decreased. The term intrapartum stillbirth rate decreased by 87% (95% CI, 68%-95%) from 0.15 per 1000 births in 1999 to 2008 to 0.02 per 1000 births in 2014 to 2018. Three in 4 term intrapartum stillbirths (70 of 95) occurred during intrapartum operative deliveries. The increased prevalence of older maternal age and obstetric risk factors were not associated with the variation in intrapartum stillbirth rates among the time periods. The prevalence of term intrapartum stillbirth was higher for individuals who gave birth in maternity units with fewer than 3000 annual births (adjusted odds ratio, 1.67; 95% CI, 1.07-2.61) than for those who gave birth in units with 3000 or more annual births.

Conclusions and Relevance

Findings of this study suggest that, despite increases in maternal and obstetric risk factors, term intrapartum stillbirth rates substantially decreased during the study period. Reasons for this decrease may be due to improvements in intrapartum care.

Contributing factors of birth asphyxia in Thailand: a case-control study

BACKGROUND

Birth asphyxia is of significant concern because it impacts newborn health from low to severe levels. In Thailand, birth asphyxia remains a leading cause of delayed developmental health in children under 5 years old. The study aimed to determine the maternal, fetal and health service factors contributing to birth asphyxia.

METHODS

A case-control design was conducted on a sample of 4256 intrapartum chart records. The samples were selected based on their Apgar scores in the first minute of life. A low Apgar score (≤ 7) was chosen for the case group (852) and a high Apgar score (> 7) for the control group (3408). In addition, a systematic random technique was performed to select 23 hospitals, including university, advanced and secondary, in eight health administration areas in Thailand for evaluating the intrapartum care service. Data analysis was conducted using SPSS statistical software.

RESULTS

The odds of birth asphyxia increases in the university and advanced hospitals but the university hospitals had the highest quality of care. The advanced and secondary hospitals had average nurse work-hours per week of more than 40 h. Multivariable logistic regression analysis found that intrapartum care services and maternal-fetal factors contributed to birth asphyxia. The odd of birth asphyxia increases significantly in late-preterm, late-term pregnancies, low-birth weight, and macrosomia. Furthermore, maternal comorbidity, non-reassuring, and obstetric emergency conditions significantly increase the odd of birth asphyxia. In addition, an excellent quality of intrapartum care, a combined nursing model, low nurse work-hours, and obstetrician-conducted delivery significantly reduced birth asphyxia.

CONCLUSION

Birth asphyxia problems may be resolved in the health service management offered by reducing the nurse work-hours. Excellent quality of care required the primary nursing care model combined with a team nursing care model. However, careful evaluation and monitoring are needed in cases of comorbidity, late-preterm, late-term pregnancies, low-birth weight, and macrosomia. Furthermore, increasing the obstetrician availability in obstetric emergencies and non-reassuring fetal status is important.

Impact of Thin Meconium on Delivery and Early Neonatal Outcomes

Several reports regarding the effects of thin meconium on maternal and neonatal outcomes are contradictory. This study evaluated the risk factors and obstetrical outcomes during deliveries complicated with thin meconium. This retrospective cohort study included all women with a singleton pregnancy, who underwent trial of labor >24 weeks of gestation, in a single tertiary center, over a six-year period. Obstetrical, delivery, and neonatal outcomes were compared between deliveries with thin meconium (thin meconium group) to deliveries with clear amniotic fluid (control group). Included in the study were 31,536 deliveries. Among them 1946 (6.2%) were in the thin meconium group and 29,590 (93.8%) were controls. Meconium aspiration syndrome was diagnosed in eight neonates in the thin meconium group and in none of the controls (0.41%, p < 0.001). In multivariate logistic regression analysis, the following adverse outcomes were found to be independently associated with increased odds ratio (OR) for thin meconium: intrapartum fever (OR 1.37, 95% CI 1.1-1.7), instrumental delivery (OR 1.26, 95% CI 1.09-1.46), cesarean delivery for non-reassuring fetal heart rate (OR 2.0, 95% CI 1.68-2.46), and respiratory distress requiring mechanical ventilation (OR 2.06, 95% CI 1.19-3.56). Thin meconium was associated with adverse obstetrical, delivery, and neonatal outcomes that should receive extra neonatal care and alert the pediatrician.

Effects of gestational age at birth on perinatal structural brain development in healthy term-born babies

Infants born in early term (37-38 weeks gestation) experience slower neurodevelopment than those born at full term (40-41 weeks gestation). While this could be due to higher perinatal morbidity, gestational age at birth may also have a direct effect on the brain. Here we characterise brain volume and white matter correlates of gestational age at birth in healthy term-born neonates and their relationship to later neurodevelopmental outcome using T2 and diffusion weighted MRI acquired in the neonatal period from a cohort (n = 454) of healthy babies born at term age (>37 weeks gestation) and scanned between 1 and 41 days after birth. Images were analysed using tensor-based morphometry and tract-based spatial statistics. Neurodevelopment was assessed at age 18 months using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). Infants born earlier had higher relative ventricular volume and lower relative brain volume in the deep grey matter, cerebellum and brainstem. Earlier birth was also associated with lower fractional anisotropy, higher mean, axial, and radial diffusivity in major white matter tracts. Gestational age at birth was positively associated with all Bayley-III subscales at age 18 months. Regression models predicting outcome from gestational age at birth were significantly improved after adding neuroimaging features associated with gestational age at birth. This work adds to the body of evidence of the impact of early term birth and highlights the importance of considering the effect of gestational age at birth in future neuroimaging studies including term-born babies.

Induction of labour from 39 weeks in low-risk multiparas with ripe cervixes: A randomised controlled trial

BACKGROUND

Induction of labour (IOL) in low-risk nulliparas at 39 weeks reduces caesarean delivery. Multiparas with ripe cervixes typically have vaginal delivery within eight hours. Delivery at night and weekend are associated with higher maternal and neonatal mortality.

AIMS

To evaluate IOL in full-term multiparas with ripe cervixes to achieve delivery at normal working hours and improve maternal satisfaction.

METHODS

A randomised trial was performed in a tertiary hospital in Malaysia. Low-risk multiparas with ripe cervixes (Bishop score ≥6) were recruited at 38⁺⁴ -40⁺⁰  weeks, then randomised to planned labour induction at 39⁺⁰  weeks or expectant care. Primary outcomes were delivery during 'normal working hours' 09:00-17:00 hours, Monday-Friday and patient satisfaction by visual numerical rating scale.

RESULTS

For IOL (n = 80) vs expectant care (n = 80) arms respectively, primary outcomes of delivery at normal working hours was 27/80 (34%) vs 29/78 (37%), relative risk (RR) 0.9, 95% CI 0.5-1.7, P = 0.41, patient satisfaction was 8.0 ± 1.8 vs 7.8 ± 1.6, P = 0.41; presentation for spontaneous labour or rupture of membranes were 27/80 (34%) vs 70/79 (89%), RR 0.4, 95% CI 0.3-0.5, P < 0.001; and for labour induction 52/80 (65%) vs 15/79 (19%), RR 3.4, 95% CI 2.1-5.5, P < 0.001. Caesarean delivery was 8/80 (10%) vs 4/79 (5%), RR 2.0, 95% CI 0.62-6.3, P = 0.25; and mean birthweight was 3.1 ± 0.3 vs 3.3 ± 0.4 kg, P = 0.06 for IOL vs expectant care, respectively.

CONCLUSION

Labour induction in low-risk multiparas does not increase births during working hours or improve patient satisfaction. Antenatal clinic visits and non-birth hospitalisation were significantly reduced.

Neonatal Morbidities in Infants Born Late Preterm at 35-36 Weeks of Gestation: A Swedish Nationwide Population-based Study

OBJECTIVE

To assess risk for neonatal morbidities among infants born late preterm at 35-36 gestational weeks, early term (37-38 weeks), and late-term (41 weeks) infants, compared with full-term (39-40 weeks) infants.

STUDY DESIGN

This nationwide population-based cohort study included 1 650 450 non-malformed liveborn singleton infants born at 35-41 weeks between 1998 and 2016 in Sweden. The relative risks for low Apgar score (0-3) at 5 minutes; respiratory, metabolic, infectious, and neurologic morbidities; and severe neonatal morbidity (composite outcome) were adjusted for maternal, pregnancy, delivery, and infant characteristics.

RESULTS

Compared with infants born at 39-40 weeks, the adjusted relative risks and proportions of infants born at 35-36 weeks were higher for metabolic morbidity 7.79 (95%, 7.61 to 7.97; 33.75% vs 3.11%), respiratory morbidity 5.54 (95% CI, 5.24 to 5.85; 5.49% vs 0.75%), severe neonatal morbidity 2.42 (95% CI, 2.27 to 2.59; 3.40% versus 1.03%), infectious morbidity 1.98 (95% CI, 1.83 to 2.14; 2.53% vs 0.95%), neurologic morbidity 1.74 (95% CI, 1.48 to 2.03; 0.54% vs 0.23%), and low Apgar score 2.07 (95% CI, 1.72 to 2.51; 0.42% vs 0.12%). The risks for respiratory, severe neonatal morbidity, infectious, neurologic morbidities, and low Apgar score were highest at 35 weeks, gradually decreased until 39 weeks, and increased during 39-41 weeks.

CONCLUSIONS

Infants born late preterm at 35-36 weeks of gestation are at increased risk of neonatal morbidities, although the absolute risks for severe neonatal morbidities are low. Our findings reinforce the need of preventing late preterm delivery to decrease the burden of neonatal morbidity and help professionals and families with a better risk assessment.

Maternal diseases and risk of hypertensive disorders of pregnancy across gestational age groups

OBJECTIVES

To estimate the risk of hypertensive disorders of pregnancy in nulliparous women with diabetes, chronic hypertension or obesity in three gestational age groups.

STUDY DESIGN

Population-based observational cohort study of 382 618 nulliparous women (94 280 with known BMI) using Medical Birth Registry of Norway and Statistics Norway. Main exposure variables were diabetes, chronic hypertension, Body Mass Index (BMI). Multiple regression analysis was performed without (model 1) and with (model 2) BMI.

MAIN OUTCOME MEASURES

Preeclampsia stratified by gestational age group at delivery: early (23⁰-33⁶ weeks), intermediate (34⁰-36⁶ weeks) and late (37⁰-43⁶ weeks), and gestational hypertension.

RESULTS

In model 1, Type 1 diabetes was associated with early (aOR = 5.0, 95%CI 3.8, 6.7), intermediate (aOR = 10.2, 95%CI 8.5, 12.3) and late preeclampsia (aOR = 2.7, 95%CI 2.4, 3.2), compared to no diabetes. Compared to normotensive women, women with chronic hypertension had an increased risk of preeclampsia in all groups: early (aOR = 8.68, 95%CI 6.94, 10.85), intermediate (aOR = 5.59, 95%CI 4.46, 7.02), late (aOR = 3.45, 95%CI 3.00, 3.96). The same trends persisted after adjusting for BMI (model 2). Obesity remained an independent risk factor for hypertensive disorders of pregnancy.

CONCLUSIONS

Maternal diabetes, chronic hypertension and obesity were associated with an increased risk of hypertensive disorders of pregnancy across all gestational age groups in nulliparous women. Adjusting for BMI did not further modify the risk in these women, although 75% of the women in the study lacked BMI data.

Midwife annual delivery workload and maternal and neonatal adverse outcomes, is there an association?

OBJECTIVE

In recent years there has been growing interest in the relationship between the workload of an individual practitioner and its short- and long-term consequences on birth outcomes. In this respect, data is limited with regard to midwives' workload. We aimed to evaluate the association between midwives' annual birth workload and the short-term, adverse maternal and neonatal outcomes occurring at birth.

STUDY DESIGN

This retrospective cohort study was performed in a single tertiary academic center between 2006 and 2018. All single, live vertex term vaginal births were included and categorized into two groups based on the midwife's median annual volume of births during the study duration. The "high-volume" and "low-volume" groups included births above and below the median annual volume, respectively as a dichotomous variable. Further analyses were performed for the annual volume by deciles. Short term maternal and neonatal outcomes were compared between groups and between deciles.

RESULTS

During the study period 140,856 births met the study criteria. The median annual volume of births of a single midwife was 152 [114-195]. Maternal and labor characteristics were comparable between the groups. Maternal outcomes were not significantly associated with the midwifes' annual workload. However, neonates delivered by midwives with "low" annual volume had 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 midwives' annual volume after controlling for the midwife, parturient and neonate's characteristics.