Effects of Litter Size and Parity on Farrowing Duration of Landrace × Yorkshire Sows

Litter size has increased and farrowing duration has also prolonged in recent years. The aim of this study was to analyze the effect of litter size and parity on farrowing duration (FAR) to estimate the possibility of selecting a short farrowing duration. We recorded 32,200 parturitions of 8420 Landrace × Yorkshire sows, determined farrowing duration, litter size, parity, gestation length. Results showed that total number of born (TNB) and parity obeyed a cubic (p = 0.0004, p = 0.004) relationship while number born alive (NBA) and number born dead (NBD) obeyed a linear (p = 0.0239, p = 0.0035) relationship with FAR. Gestation length obeyed a linear (p = 0.02) relationship with FAR. FAR of sows with stillbirth was longer than that of sows without stillbirth. Stillbirth rate increased rapidly from about 2% to 4%, especially when FAR was over 240 min. FAR gradually prolonged with the parities. FAR of 7th parity sows was longer than that of 1st~6th parity sows (p < 0.05), but different parity sows had little difference in the same FAR interval except for gilts. Results indicated it was possible and necessary to consider FAR into pig breeding without worrying about decreasing of live litter size or negative effect of parity if FAR was shorter than 300 min.

Epidemiology of Antepartum Stillbirths in Austria—A Population-Based Study between 2008 and 2020

(1) Background: Across Europe, the incidence of antepartum stillbirth varies greatly, partly because of heterogeneous definitions regarding gestational weeks and differences in legislation. With this study, we sought to provide a comprehensive overview on the demographics of antepartum stillbirth in Austria, defined as non-iatrogenic fetal demise ≥22+0 gestational weeks (/40). (2) Methods: We conducted a population-based study on epidemiological characteristics of singleton antepartum stillbirth in Austria between January 2008 and December 2020. Data were derived from the validated Austrian Birth Registry. (3) Results: From January 2008 through December 2020, the antepartum stillbirth rate ≥20+0/40 was 3.10, ≥22+0/40 3.14, and ≥24+0/40 2.83 per 1000 births in Austria. The highest incidence was recorded in the federal states of Vienna, Styria, and Lower and Upper Austria, contributing to 71.9% of all stillbirths in the country. In the last decade, significant fluctuations in incidence were noted: from 2011 to 2012, the rate significantly declined from 3.40 to 3.07‰, whilst it significantly increased from 2.76 to 3.49‰ between 2019 and 2020. The median gestational age of antepartum stillbirth in Austria was 33+0 (27+2–37+4) weeks. Stillbirth rates ≤26/40 ranged from 164.98 to 334.18‰, whilst the lowest rates of 0.58–8.4‰ were observed ≥36/40. The main demographic risk factors were maternal obesity and low parity. (4) Conclusions: In Austria, the antepartum stillbirth rate has remained relatively stable at 2.83–3.10 per 1000 births for the last decade, despite a significant decline in 2012 and an increase in 2020.

Changes in the Antenatal Utilization of High-Risk Obstetric Services and Stillbirth Rate during the COVID-19 Pandemic

Objective The primary objective of this study was to evaluate coronavirus 2019 (COVID-19) pandemic–related changes in the antenatal utilization of high-risk obstetric services. Our secondary objective was to characterize change in stillbirth rate during the pandemic. Study Design This is a retrospective, observational study performed at a single, tertiary care center. Maternal-Fetal Medicine (MFM) visits, ultrasounds, and antenatal tests of fetal well-being during the pandemic epoch (2020), which spans the first 12 weeks of the year to include pandemic onset and implementation of mitigation efforts, were compared with the same epoch of the three preceding years visually and using general linear models to account for week and year effect. An analysis of stillbirth rate comparing the pandemic time period to prepandemic was also performed. Results While there were decreased MFM visits and antenatal tests of fetal well-being during the pandemic epoch compared with prepandemic epochs, only the decrease in MFM visits by year was statistically significant (p < 0.001). The stillbirth rate during the pandemic epoch was not significantly different when compared with the prepandemic period and accounting for both week (p = 0.286) and year (p = 0.643) effect. Conclusion The COVID-19 pandemic resulted in a significant decrease in MFM visits, whereas obstetric ultrasounds and antenatal tests of fetal well-being remained unchanged. While we observed no change in the stillbirth rate compared with the prepandemic epoch, our study design and sample size preclude us from making assumptions of association. Our findings may support future work investigating how changes in prenatal care for high-risk obstetric patients influence perinatal outcomes. Key Points

Intra-urban differentials of fetal mortality in clusters of social vulnerability in São Paulo Municipality, Brazil

This study aimed to analyze the distribution of stillbirths by birth weight, type of death, the trend of Stillbirth Rate (SBR), and avoidable causes of death, according to social vulnerability clusters in São Paulo Municipality, 2007–2017. Social vulnerability clusters were created with the k-means method. The Prais-Winsten generalized linear regression was used in the trend of SBR by < 2500 g, ≥ 2500 g, and total deaths analysis. The Brazilian list of avoidable causes of death was adapted for stillbirths. There was a predominance of antepartum stillbirths (70%). There was an increase in SBR with the growth of social vulnerability from the center to the outskirts of the city. The cluster with the highest vulnerability presented SBR 69% higher than the cluster with the lowest vulnerability. SBR ≥ 2500 g was decreasing in the clusters with the high vulnerability. There was an increase in SBR of avoidable causes of death of the cluster from the lowest to the highest vulnerability. Ill-defined causes of death accounted for 75% of deaths in the highest vulnerability area. Rates of fetal mortality and avoidable causes of death increased with social vulnerability. The trend of reduction of SBR ≥ 2500 g may suggest improvement in prenatal care in areas of higher vulnerability.

Preterm birth, stillbirth and early neonatal mortality during the Danish COVID-19 lockdown

Using provisional or opportunistic data, three nationwide studies (The Netherlands, the USA and Denmark) have identified a reduction in preterm or extremely preterm births during periods of COVID-19 restrictions. However, none of the studies accounted for perinatal deaths. To determine whether the reduction in extremely preterm births, observed in Denmark during the COVID-19 lockdown, could be the result of an increase in perinatal deaths and to assess the impact of extended COVID-19 restrictions, we performed a nationwide Danish register-based prevalence proportion study. We examined all singleton pregnancies delivered in Denmark during the COVID-19 strict lockdown calendar periods (March 12–April 14, 2015-2020, N = 31,164 births) and the extended calendar periods of COVID-19 restrictions (February 27–September 30, 2015-2020, N = 214,862 births). The extremely preterm birth rate was reduced (OR 0.27, 95% CI 0.07 to 0.86) during the strict lockdown period in 2020, while perinatal mortality was not significantly different. During the extended period of restrictions in 2020, the extremely preterm birth rate was marginally reduced, and a significant reduction in the stillbirth rate (OR 0.69, 0.50 to 0.95) was observed. No changes in early neonatal mortality rates were found.Conclusion: Stillbirth and extremely preterm birth rates were reduced in Denmark during the period of COVID-19 restrictions and lockdown, respectively, suggesting that aspects of these containment and control measures confer an element of protection. The present observational study does not allow for causal inference; however, the results support the design of studies to ascertain whether behavioural or social changes for pregnant women may improve pregnancy outcomes. What is Known:• The aetiologies of preterm birth and stillbirth are multifaceted and linked to a wide range of socio-demographic, medical, obstetric, foetal, psychosocial and environmental factors.• The COVID-19 lockdown saw a reduction in extremely preterm births in Denmark and other high-income countries. An urgent question is whether this reduction can be explained by increased perinatal mortality. What is New:• The reduction in extremely preterm births during the Danish COVID-19 lockdown was not a consequence of increased perinatal mortality, which remained unchanged during this period.• The stillbirth rate was reduced throughout the extended period of COVID-19 restrictions.

Factors associated with stillbirths among women delivering at a resource limited tertiary hospital in Malawi

Background: Stillbirths remain a major public health issue worldwide with an estimated 3 million deaths per year globally. We investigated the factors associated with stillbirths in fetuses of at least 28 weeks’ gestation or 1000 grams at birth. Methods: We performed a hospital-based, cross-sectional study among women who delivered stillbirths at Kamuzu Central Hospital (KCH) in Lilongwe, Malawi from May-November 2017. Eligible women were enrolled after obtaining informed consent, and their demographic and reproductive health information was collected. Blood samples were collected for full blood count, malaria, blood glucose, syphilis, and HIV testing, and the probable risk factors associated with stillbirths were assessed. Results: A total of 1,687 deliveries with 126 stillbirths occurred during the 6-month period, representing a stillbirth rate of 79 per 1,000 births. Seventy percent of these stillbirths were diagnosed on admission at KCH, and about 49% were fresh stillbirths. Half of the stillbirths had a birthweight of at least 2,500g, and the majority of these stillbirths were fresh (60%). The following factors were associated with stillbirth: uterine rupture (15.1%), placental abruption (14.3%), Hypertension (10.3%), obstructed/prolonged labor (5.8%), syphilis (7.1%), malaria (2.4%), congenital anomalies (2.4%), and diabetes (1.5%). Conclusions: The stillbirth rate at KCH is high, and most fetal deaths occurred prior to arrival at KCH. Although most of the stillbirths were unexplained, uterine rupture and abruption placenta emerged as major factors associated with stillbirths and these are largely preventable even in resource limited settings.

437Comparison of stillbirth trends in Wales and Western Australia using pooled routinely collected health data

Background As there are variations in stillbirth rates and trends, even among high income countries, international comparisons can provide insights into how reductions in stillbirths can be achieved. We compared stillbirth rates and trends over time in Wales and Western Australia (WA). Methods We pooled population-based data of all births of at least 24 weeks’ gestation occurring between 1993-2015 in Wales and WA, divided into 6 time-periods. The stillbirth rate per 1,000 births was estimated for each cohort in each time-period. Multivariable Poisson regression analyses, were performed to evaluate the interaction between cohort and time-period. relative risk (RRs) and 95% Confidence Intervals (CIs) for each time-period and cohort were calculated. Results The overall stillbirth rate declined by 15.9% in Wales and 40.4% in WA. Using WA and 1993-1996 as the reference group, the adjusted RRs for stillbirths at 39-41 weeks’ gestation in the most recent study period (2013-15) were 0.85 (95% CI 0.64 to 1.13) in Wales and 0.51 (95% CI 0.36 to 0.73) in WA. Conclusions The stillbirth rate disparities between Wales and WA have widened in the last two decades (especially among term births). Some of these differences may be partially explained by maternal lifestyle behaviours such as smoking, but we had insufficient population-level data to investigate their contribution. Key messages The stillbirth rate was persistently higher in Wales than WA from 1993 to 2015, with widening disparities after adjustment for important risk factors.

Immunization against Gonadotropin-Releasing Hormone in Female Beef Calves to Avoid Pregnancy at Time of Slaughter

Precocious puberty in beef heifers can result in unwanted pregnancies due to accidental breeding by farm bulls. Inbreeding, premature calving followed by dystocia and a high stillbirth rate or slaughtering of pregnant heifers are the consequences of this behaviour. The aim of the study was to postpone puberty by using Improvac®, an anti-GnRH vaccine. Therefore, n = 25 calves were twice vaccinated, once at the age of 5 and then at 6.5 months. n = 24 calves served as unvaccinated case controls. The onset of puberty was assigned if progesterone analysis in the blood exceeded 1 ng/mL. Progesterone values were excluded if the corresponding serum cortisol levels were ≥60 nmol/L. Our target was met, as in the vaccinated group none of the calves exceeded a progesterone value >1 ng/mL until the scheduled age of slaughter at 11 months and only 12.5% of the animals exceeded a progesterone value of 1 ng/mL over the whole measuring period (>400 days) compared with 56.5% of the calves in the control group. In conclusion, the favourable results from our study using the vaccine Improvac® represent an animal-friendly, non-invasive and reliable way to avoid early pregnancy in heifers as well as the slaughter of pregnant cattle.