Impacts of COVID-19 pandemic on preterm birth: a systematic review and meta-analysis

Maternal inflammatory and microbial drivers of low birthweight in low- and middle-income countries

BACKGROUND

Low birthweight (LBW) is when an infant is born too soon or too small, and it affects one in seven infants in low- and middle-income countries. LBW has a significant impact on short-term morbidity and mortality, and it impairs long-term health and human capital. Antenatal microbial and inflammatory exposure may contribute to LBW.

METHODS

Ovid-Medline, Embase and Cochrane databases were searched for English-language articles evaluating inflammatory, microbial or infective causes of LBW, small-for-gestational age, intra-uterine growth restriction or prematurity. Inclusion criteria were human studies including published data; conference abstracts and grey literature were excluded. A narrative synthesis of the literature was conducted.

RESULTS

Local infections may drive the underlying causes of LBW: for example, vaginitis and placental infection are associated with a greater risk of prematurity. Distal infection and inflammatory pathways are also associated with LBW, with an association between periodontitis and preterm delivery and environmental enteric dysfunction and reduced intra-uterine growth. Systemic maternal infections such as malaria and HIV are associated with LBW, even when infants are exposed to HIV but not infected. This latter association may be driven by chronic inflammation, co-infections and socio-economic confounders. Antimicrobial prophylaxis against other bacteria in pregnancy has shown minimal impact in most trials, though positive effects on birthweight have been found in some settings with a high infectious disease burden.

CONCLUSION

Maternal inflammatory and infective processes underlie LBW, and provide treatable pathways for interventions. However, an improved understanding of the mechanisms and pathways underlying LBW is needed, given the impact of LBW on life-course.

Impact of SARS-COV-2 Infection on Maternal, Obstetric and Neonatal Outcomes in a Cohort of Vaccinated Women: A Pilot Study

We aimed to investigate the impact of COVID-19 infection on maternal characteristics and obstetric and neonatal outcomes in a cohort of women in labor previously vaccinated who tested positive for SARS-CoV-2 infection, compared to aged-matched healthy controls. A retrospective case-control study was conducted among 66 women in labor. Clinical data were obtained from medical records. The attendance rates at childbirth and parenting classes, as well as the implementation of a birth plan, were significantly lower in the COVID-19 infection group (6.1% vs. 48.5%, <0.001; 6.1% vs. 33.3%, p = .005, respectively). Women with COVID-19 had a higher prevalence of prolonged postpartum hospital stay (33.3% vs. 9.1%, p = .016), and significantly higher prevalence of spontaneous preterm birth (27.3% vs. 1.09%, p = .006). Breastfeeding within the first 24 hr was also lower in women with COVID-19 (72.7% vs. 97.0%, p = .006). Maternal characteristics and neonatal outcomes are influenced by COVID-19 infection in vaccinated women. Complications include spontaneous preterm birth, prolonged postpartum hospital stay, and lack of breastfeeding within the first 24 hr. Childbirth education, parenting classes and implementing a birth plan may be associated with a decreased risk of COVID-19 infection.

Socioeconomic disparities in changes to preterm birth and stillbirth rates during the first year of the COVID-19 pandemic: a study of 21 European countries

BACKGROUND

Despite concerns about worsening pregnancy outcomes resulting from healthcare restrictions, economic difficulties and increased stress during the COVID-19 pandemic, preterm birth (PTB) rates declined in some countries in 2020, while stillbirth rates appeared stable. Like other shocks, the pandemic may have exacerbated existing socioeconomic disparities in pregnancy, but this remains to be established. Our objective was to investigate changes in PTB and stillbirth by socioeconomic status (SES) in European countries.

METHODS

The Euro-Peristat network implemented this study within the Population Health Information Research Infrastructure (PHIRI) project. A common data model was developed to collect aggregated tables from routine birth data for 2015-2020. SES was based on mother's educational level or area-level deprivation/maternal occupation if education was unavailable and harmonized into low, medium and high SES. Country-specific relative risks (RRs) of PTB and stillbirth for March to December 2020, adjusted for linear trends from 2015 to 2019, by SES group were pooled using random effects meta-analysis.

RESULTS

Twenty-one countries provided data on perinatal outcomes by SES. PTB declined by an average 4% in 2020 {pooled RR: 0.96 [95% confidence intervals (CIs): 0.94-0.97]} with similar estimates across all SES groups. Stillbirths rose by 5% [RR: 1.05 (95% CI: 0.99-1.10)], with increases of between 3 and 6% across the three SES groups, with overlapping confidence limits.

CONCLUSIONS

PTB decreases were similar regardless of SES group, while stillbirth rates rose without marked differences between groups.

Analysis of anthropometric outcomes in Indian children during the COVID-19 pandemic using National Family Health Survey data

BACKGROUND

Disruptions in food, health, and economic systems during the COVID-19 pandemic may have adversely affected child health. There is currently limited research on the potential effects of the COVID-19 pandemic on stunting, wasting, and underweight status of young children.

METHODS

We examine the short-term associations between the pandemic and anthropometric outcomes of under-5 children (n = 232,920) in India, using data from the National Family Health Survey (2019-2021). Children surveyed after March 2020 are considered as the post-COVID group, while those surveyed earlier are considered as pre-COVID. Potential biases arising from differences in socioeconomic characteristics of the two groups are mitigated using propensity score matching methods.

RESULTS

Post-COVID children surveyed in 2020 and 2021 have 1.2% higher underweight rates, 1.2% lower wasting rates, 0.1 lower height-for-age z-scores (HAZ), and 0.04 lower weight-for-height z-scores as compared with matched pre-COVID children. Post-COVID children surveyed in 2020 have 1.6%, 4.6%, and 2.4% higher stunting, underweight, and wasting rates, respectively, and 0.07 lower HAZ, as compared with matched pre-COVID children. Reductions in nutritional status are largest among children from households in the poorest wealth quintiles.

CONCLUSIONS

These findings indicate a trend towards a recovery in child anthropometric outcomes in 2021 after the initial post-pandemic reductions. The resilience of health and food systems to shocks such as COVID-19 should be strengthened while immediate investments are required to decrease child malnutrition and improve broader child health outcomes.

Impact of COVID-19 on pregnancy and fetal outcomes in women with multiple sclerosis

BACKGROUND

In the general population, maternal COVID-19 is associated with worse maternal and fetal outcomes. Two previous studies have assessed COVID-19 clinical outcomes in pregnant women with multiple sclerosis (MS), but there are no data about maternal and fetal outcomes.

OBJECTIVES

In this multicenter study, we aimed to assess maternal and fetal outcomes in pregnant women with MS and COVID-19 infection.

METHODS

We recruited pregnant patients with MS who contracted COVID-19 and were followed up in Italian and Turkish Centers, during 2020-2022. A control group was extracted from a previous Italian cohort. Associations between group (COVID-19 or healthy patients) and clinical outcomes (maternal complications, fetal malformations, and spontaneous abortion) were investigated with a weighted logistic regression where propensity score-based inverse probability of treatment weighting (IPTW) approach was applied for adjusting for difference in baseline confounders.

RESULTS

In the multivariable analysis, COVID-19 during pregnancy was associated with a higher risk of maternal complications (odd ratio (OR) = 2.12; 95% confidence interval (CI) = 1.32-3.48; p = 0.002), while it was not associated with higher risk of spontaneous abortion and fetal malformations.

CONCLUSION

Our data indicate that COVID-19 during pregnancy increases the risk of maternal complications, while it seems to have no significant impact on fetal outcomes.

Preterm births among male and female conception cohorts in France during initial COVID-19 societal restrictions

PURPOSE

A recent meta-analysis finds reduced risk of preterm birth (PTB; <37 weeks gestational age) during the initial stage of COVID-19 in which infection rates remained relatively low but many societies imposed restrictions on movement. None of this work, however, examines sex-specific responses despite much literature on other ambient "shocks" which would predict male sensitivity. We use a conception cohort approach to explore potential sex-specific PTB responses in France, a country which imposed a lockdown in Spring 2020.

METHODS

We applied interrupted time series methods using national data in France for 207 weeks among 1403,284 males and 1341,359 females conceived from 19 Jan 2016 to 6 Jan 2020.

RESULTS

For males in utero, the 1st COVID-19 societal lockdown corresponds with a - 0.60 per 100 conception reduction in PTB cases per week, for 12 consecutive weeks (95% confidence interval [CI]: -.36, -.84). For females in utero, the PTB reduction is smaller (-0.40 reduction per 100 conceptions, for 10 consecutive weeks, 95% CI: -.15, -.61). A formal test of sex differences in the PTB response indicates a stronger reduction in male (vs. female) PTB during the lockdown (p = .001).

CONCLUSIONS

Explanations for the counterintuitive reduction in PTB during COVID-19 among cohorts in utero during Spring 2020 should consider mechanisms that disproportionately affect males.

Preterm birth and stillbirth during COVID-19 pandemic in Bihor County/Romania

Background

International studies have reported conflicting data about the effects of COVID-19 pandemic policy measures on maternal and neonatal health. A major impact was reported on stillbirth and prematurity. The published literature suggests that the economic setting influenced the effects of imposed mitigation measures with a more severe effect in low-income countries.

Objectives

Our objective is to compare pregnancy outcomes at the only tertiary Maternity Hospital in Bihor County-Romania before and during the COVID-19 pandemic. This study aims to observe and document differences in perinatal outcomes across these periods, without inferring direct causation related to the pandemic or its associated restrictions.

Materials and methods

We used data from the registries of Public Health Services Bihor to conduct a retrospective cohort analysis of preterm births and stillbirths during the COVID-19 pandemic in Bihor County, Romania. Pregnancy outcomes were compared between the pandemic period (March 2020-February 2022) to the corresponding historical pre-COVID-19 period (March 2018-February 2020). Maternal socio-demographic variables and neonatal characteristics of these periods were also examined.

Results

The COVID-19 pandemic period was associated with an increase in the stillbirth rate (RR: 1.53, 95% CI, 1.05-2.23). Preterm birth was significantly impacted during this period and showed changes when analyzing gestational age (RR: 0.88, 95% CI, 0.79-0.96) or birth weight (RR: 0.91, 95% CI, 0.82-1.00). The main cause of stillbirth was intrauterine asphyxia due to placental causes (67.6%) or cord pathology (12.6%), the most frequently encountered maternal pathology was cardiovascular (28.3%) or infectious (21.7%). Our study revealed no significant changes in terms of maternal and neonatal characteristics during the two-year pandemic period.

Conclusions

Lockdown restrictions in Bihor County, Romania were associated with an increase in stillbirths, whilst preterm birth rate decreased. This raises concerns about whether pandemic policy measures may have led to a failure in identifying and offering proper care for pregnant women who were more likely to experience an antepartum loss. Further studies across the globe are needed in order to integrate comparable data that will help develop adequate protocols and policies for protecting maternal and child health during the next pandemic that will follow.

Newborn Hospitalizations Before and During COVID-19 Pandemic in Poland: A Comparative Study Based on a National Hospital Registry

Objectives: There are limited data on the impact of the COVID-19 outbreak in Poland on newborn health. The aim of the study is to show recent information on hospitalizations of newborns in Poland in the pre-pandemic and COVID-19 pandemic era. Methods: A retrospective, population-based study was conducted using data from hospital discharge records of patients hospitalized in 2017-2021. Results: The data on which the study was based consisted of a substantial number of 104,450 hospitalization records. Annual hospitalization rate was estimated to be 50.3-51.9 per 1,000 in 2017-2019, 56 per 1,000 in 2020 and it rose to 77.7 per 1,000 in 2021. In comparison to the pre-pandemic period, in the COVID-19 era, we observed significantly more hospitalization cases of newborns affected by maternal renal and urinary tract diseases (p < 0.001), syndrome of infant of mother with gestational diabetes (p < 0.001), maternal complications of pregnancy (p < 0.001). In the COVID-19 era, the prevalence of COVID-19 among newborns was 4.5 cases per 1,000 newborn hospitalizations. Conclusion: The COVID-19 pandemic outbreak could significantly contribute to qualitative and quantitative changes in hospitalizations among newborns.

Assessing the Impact of COVID-19 Vaccination on Preterm Birth: A Systematic Review with Meta-Analysis

During the coronavirus diseases 2019 (COVID-19) pandemic, the safety and efficacy of vaccination during pregnancy, particularly regarding the risk of preterm birth, have been a subject of concern. This systematic review aims to evaluate the impact of COVID-19 vaccination on preterm birth risk and to inform clinical practice and public health policies. Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a database search included PubMed, Embase, and Scopus, conducted up until October 2023. Inclusion criteria focused on studies that examined COVID-19 vaccination during pregnancy and its correlation with preterm birth, defined as a birth before 37 weeks of gestation. Six studies met these criteria, encompassing 35,612 patients. A quality assessment was performed using the Newcastle-Ottawa Scale and the Cochrane Collaboration's tool, with the risk of bias evaluated via a funnel plot analysis and an Egger's regression test. The studies demonstrated geographical diversity, mainly from Israel, Romania, and the United States, with a blend of prospective and retrospective designs. The patient cohort's mean age was 31.2 years, with common comorbidities such as gestational diabetes and obesity affecting 9.85% of the total population. The vaccination types varied across the studies, with BNT162b2 being the most used. The results indicated a low heterogeneity among the included studies, evidenced by a Cochran's Q statistic of 2.10 and an I2 statistic of 13%. The meta-analysis yielded a pooled odds ratio (OR) for a preterm birth risk post-vaccination of approximately 1.03 (95% CI: 0.82-1.30), suggesting no significant increase in preterm birth risk was associated with COVID-19 vaccination. Notable findings included a low preterm birth rate (as low as 0.6% and up to 6.1%) with minimal differences in neonatal outcomes, such as birth weight and APGAR (appearance, pulse, grimace, activity, and respiration) scores between vaccinated and unvaccinated groups. This study concludes that a COVID-19 vaccination during pregnancy does not significantly increase the risk of preterm birth. These findings are crucial for reassuring healthcare providers and pregnant women about the safety of COVID-19 vaccines and supporting their use in public health strategies during the pandemic.

Impacts of the COVID-19 pandemic on early pregnancy outcomes among women undergoing frozen-thawed embryo transfer: a retrospective cohort study

The effect of COVID-19 pandemic on early pregnancy outcomes among women undergoing frozen-thawed embryo transfer (FET) remains unclear. We aimed to evaluate whether early pregnancy outcomes were altered in patients undergoing FET during the pandemic. In this retrospective cohort study, women conceived through FET in 2016-2021 from two hospitals in China were included. The early pregnancy outcomes were compared using Logistic regression model, including biochemical pregnancy rate (BPR), clinical pregnancy rate (CPR), and early pregnancy loss rate (EPLR). A total of 16,669 (67.2%) and 6,113 (26.8%) FET cycles enrolled before and during the pandemic, respectively. Univariate analyses showed that women undergoing FET during the pandemic had significantly increased BPR (72.9% vs. 69.7%) and CPR (59.5% vs. 55.0%), and significantly decreased EPLR (13.7% vs. 16.7%) compared to pre-pandemic (all P < 0.001). Moreover, after adjustment, the results were in accordance with univariate analysis for CPR [adjusted OR (95%CI) = 1.08 (1.01-1.14)] and EPLR [adjusted OR (95%CI) = 0.82 (0.73-0.91)], while the statistical significance between BPR and the pandemic disappeared. In summary, women conceived by FET did not have a reduced possibility of clinical pregnancy and a higher risk of early pregnancy loss during the pandemic compared with the pre-pandemic.

The COVID-19 pandemic affects pregnancy complications and delivery outcomes in Japan: a large-scale nationwide population-based longitudinal study

The impact of the coronavirus disease 2019 (COVID-19) pandemic on pregnancy outcomes in Japan at the national level is unclear. This study aimed to assess the impact of the pandemic on pregnancy complications and delivery outcomes in Japan using nationwide population-based longitudinal data. Secondary data from the Japan Society of Obstetrics and Gynecology from 2016 to 2020 were analyzed. Obstetric information, pregnancy complications, and delivery information of pregnant women over 22 weeks of gestation were compared before and during the pandemic. The trends of hypertensive disorder of pregnancy, fetal growth restriction, and APGAR < 7 increased, whereas those of preterm birth and low birth weight decreased during the COVID-19 pandemic. Pregnancy complications and delivery outcomes have worsened during the COVID-19 pandemic in Japan. Social changes caused by unprecedented situations may have massively influenced pregnancy in several ways. Our findings suggest that even in mild lockdowns like those in Japan, the introduction of social fear during the pandemic might negatively impact pregnancy outcomes.

Stress of Prematurity in the Experience of the COVID-19 Pandemic-Current State of Knowledge

Stress is a process that triggers various physiological, hormonal and psychological mechanisms in response to a threat, which significantly affects the health of an individual. The COVID-19 pandemic introduced a lot of social changes that required constant adaptation to unfavorable conditions. The aim of the study was to assess the impact of stress related to this pandemic on pregnant women, mothers of premature infants and their families, and on obstetric complications, particularly preterm birth. A comprehensive literature review was performed using electronic databases such as Pubmed, Science Direct and Google Scholar. Keywords such as: "prematurity"; "pregnancy"; "stress"; "COVID-19" and various combinations of the above were used. Maternal stress and anxiety increase the levels of corticotropin-releasing hormone (CRH) in the placenta, which in turn affects the incidence of preterm birth and many other related maternal and neonatal complications. In addition, it was found that SARS-CoV-2 infection may increase the risk of this phenomenon. The COVID-19 pandemic has adversely affected preterm birth rates and the mental health of mothers of preterm infants, exacerbating their negative experience of having a premature baby. More research is needed to demonstrate the long-term effects of COVID-19 stress on prematurity.

An evaluation of the association between lockdown during the SARS-CoV-2 pandemic and prematurity at the Nice University Hospital

Aim

To study the association between lockdown in France due to the SARS-CoV-2 pandemic and premature births at the Nice University Hospital.

Methods

Data concerning neonates born at the level III maternity of the Nice University Hospital and immediately hospitalised in the neonatal reanimation unit or the neonatology department of the hospital with their mothers between the 1st of January 2017 and the 31st of December 2020, included.

Results

We did not find a significant decrease in the global number of premature births <37 weeks of gestation, in low weight at birth or a significant increase in stillbirths during lockdown compared to a period with no lockdown. The profiles of the mothers and their newborns were compared when birth occurred during lockdown vs. no lockdown.

Conclusion

We did not find any evidence of an association between lockdown and prematurity at the Nice University Hospital. This result is in agreement with meta-analyses published in the medical literature. The possible decrease in factors of risk of prematurity during lockdown is controversial.

Effect of COVID-19 on Pregnancy and Neonate's Vital Parameters: A Systematic Review

Background

COVID-19 is a new pandemic, which was declared by the World Health Organization in 2019 as a threat to public health. According to numerous reports, it can have negative consequences for pregnant women, labour, and neonates born to infected mothers. The aim of this paper was to gather the evidence and to present a summary of the results of studies concerning COVID-19 in pregnant women and their neonates.

Methods

Articles from prestigious journals covering the period from 2020 to February 2023, relevant review papers, and original research articles from PubMed were analysed. In order to analyse the available research literature, the Web of Science, Scopus, and PubMed databases were used, in which the search for articles was conducted using terms ("pregnancy," "coronavirus," "SARS-CoV-2," and "newborn") and using PRISMA (Preferred Reporting Items for Systemic Reviews and Meta-Analysis) guidelines for clinical trials. Meta-analyses and systematic reviews (2022-2023) on symptoms, neonatal course, and risk of COVID-19 infection have been summarized. Summary of meta-analyses and systematic reviews (2022-2023) on the effect and adverse reaction of the COVID-19 vaccination is presented.

Results

As a result of the research conducted, it was confirmed that in most pregnant women, no serious signs of the infection were observed, although isolated cases of death related to COVID-19 in pregnant women were reported. Several authors called attention to the more severe course of the infection in pregnant women with obesity. It seemed that no vertical transmission from mother to child was occurring. Nevertheless, the information was not clinching. The condition of the neonates born to mothers with COVID-19 was in most cases described as normal; however, some papers reported deaths of infected neonates.

Conclusions

Due to insufficient data, further research is necessary. Further studies and follow-up are recommended, which would make possible an assessment of remote effects of COVID-19 on pregnancy and vital parameters of the newborn.