Pregnancy and birth rate outcomes in alpacas (Vicugna pacos) inseminated with frozen semen using two commercial extenders

The aim of this study was to evaluate alpaca pregnancy outcomes and birth rates of females inseminated with frozen semen using two commercial extenders. A total of 18 ejaculates from 8 adult alpaca males were obtained with artificial vagina, and macroscopic and microscopic semen characteristics were assessed. Afterwards, samples were divided into two aliquots, diluted with Biladyl® B or AndroMed®, and cooled for 2 h at 5°C. At that moment, sperm motility was evaluated, and samples were frozen through a gradual descent of temperature using a liquid nitrogen tank. To analyse frozen sperm quality, samples were thawed at 38°C for 30 s. Even though a significant decrease in sperm motility and viability was detected when thawed (p < .05), no superiority was found between the two commercial extenders (Biladyl® B vs. AndroMed®). A total of 36 alpaca females were artificially inseminated (AI) between 30 and 34 h post-injection of a GnRH analogue, administered when a growing dominant follicle was detected through transrectal palpation and ultrasonography. Obtained pregnancy rates were similar between Biladyl® B (33.3%, 6/18) and AndroMed® (22.2%, 4/18). No significant differences were detected in birth rates between the two tested extenders, obtaining 4 and 3 births for Biladyl® and AndroMed®, respectively. In conclusion, alpaca pregnancies and alive offspring can be obtained through AI with frozen semen at similar efficiency rates using commercial diluents, Biladyl® B or AndroMed®.

State-specific fertility rate changes across the USA following the first two waves of COVID-19

STUDY QUESTION

How did the first two coronavirus disease 2019 (COVID-19) waves affect fertility rates in the USA?

SUMMARY ANSWER

States differed widely in how their fertility rates changed following the COVID-19 outbreak and these changes were influenced more by state-level economic, racial, political, and social factors than by COVID-19 wave severity.

WHAT IS KNOWN ALREADY

The outbreak of the COVID-19 pandemic contributed to already declining fertility rates in the USA, but not equally across states. Identifying drivers of differential changes in fertility rates can help explain variations in demographic shifts across states in the USA and motivate policies that support families in general, not only during crises.

STUDY DESIGN, SIZE, DURATION

This is an ecological study using state-level data from 50 US states and the District of Columbia (n = 51). The study period extends from 2020 to 2021 with historical data from 2016 to 2019. We identified Wave 1 as the first apex for each state after February 2020 and Wave 2 as the second apex, during Fall/Winter 2020-2021.

PARTICIPANTS/MATERIALS, SETTING, METHODS

State-level COVID-19 wave severity, defined as case acceleration during each 3-month COVID-19 wave (cases/100 000 population/month), was derived from 7-day weekly moving average COVID-19 case rates from the US Centers for Disease Control and Prevention (CDC). State-level fertility rate changes (change in average monthly fertility rate/100 000 women of reproductive age (WRA)/year) were derived from the CDC Bureau of Vital Statistics and from 2020 US Census and University of Virginia 2021 population estimates 9 months after each COVID-19 wave. We performed univariate analyses to describe national and state-level fertility rate changes following each wave, and simple and multivariable linear regression analyses to assess the relation of COVID-19 wave severity and other state-level characteristics with fertility rate changes.

MAIN RESULTS AND THE ROLE OF CHANCE

Nationwide, fertility dropped by 17.5 births/month/100 000 WRA/year following Wave 1 and 9.2 births/month/100 000 WRA/year following Wave 2. The declines following Wave 1 were largest among majority-Democrat, more non-White states where people practiced greater social distancing. Greater COVID-19 wave severity was associated with steeper fertility rate decline post-Wave 1 in simple regression, but the association was attenuated when adjusted for other covariates. Adjusting for the economic impact of the pandemic (hypothesized mediator) also attenuated the effect. There was no relation between COVID-19 wave severity and fertility rate change following Wave 2.

LIMITATIONS, REASONS FOR CAUTION

Our study harnesses state-level data so individual-level conclusions cannot be inferred. There may be residual confounding in our multivariable regression and we were underpowered to detect some effects.

WIDER IMPLICATIONS OF THE FINDINGS

The COVID-19 pandemic initially impacted the national fertility rate but, overall, the fertility rate rebounded to the pre-pandemic level following Wave 2. Consistent with prior literature, COVID-19 wave severity did not appear to predict fertility rate change. Economic, racial, political, and social factors influenced state-specific fertility rates during the pandemic more than the severity of the outbreak alone. Future studies in other countries should also consider whether these factors account for internal heterogeneity when examining the impact of the COVID-19 pandemic and other crises on fertility.

STUDY FUNDING/COMPETING INTEREST(S)

L.G.K. received funding from the National Institute of Environmental Health Sciences (R00ES030403), M.C. from the National Science Foundation Graduate Research Fellowship Program (20-A0-00-1005789), and M.L. and E.S. from the National Institute of Environmental Health Sciences (R01ES032808). None of the authors have competing interests.

TRIAL REGISTRATION NUMBER

N/A.

The impact of COVID-19 on the birth rate in Nigeria: a report from population-based registries

Background and objectives

Coronavirus disease 2019 (COVID-19) is a pandemic that has become a major source of morbidity and mortality worldwide, affecting the physical and mental health of individuals influencing reproduction. Despite the threat, it poses to maternal health in sub-Saharan Africa and Nigeria, there is little or no data on the impact it has on fertility, conception, gestation and birth. To compare the birth rate between pre-COVID and COVID times using selected months of the year.

Materials and methods

This was a secondary analysis of cross-sectional analytical study data from the birth registries of three tertiary hospitals, comparing two years [2019 (Pre-COVID)] versus [2020 (COVID era)] using three months of the year (October to December). The data relied upon was obtained from birth registries in three busy maternity clinics all within tertiary hospitals in South-East Nigeria and we aimed at discussing the potential impacts of COVID-19 on fertility in Nigeria. The secondary outcome measures were; mode of delivery, booking status of the participants, maternal age and occupation.

Results

There was a significant decrease in tertiary-hospital based birth rate by 92 births (P = 0.0009; 95% CI: -16.0519 to -4.1481) among mothers in all the three hospitals in 2020 during the COVID period (post lockdown months) of October to December. There was a significant difference in the mode of delivery for mothers (P = 0.0096) with a 95% confidence interval of 1.0664 to 1.5916, as more gave birth through vaginal delivery during the 2020 COVID-19 period than pre-COVID-19.

Conclusion

Tertiary-hospital based birth rates were reduced during the pandemic. Our multi-centre study extrapolated on possible factors that may have played a role in this decline in their birth rate, which includes but is not limited to; decreased access to hospital care due to the total lockdowns/curfews and worsening inflation and economic recession in the country.

Early assessment of the relationship between the COVID-19 pandemic and births in high-income countries

Drawing on past pandemics, scholars have suggested that the COVID-19 pandemic will bring about fertility decline. Evidence from actual birth data has so far been scarce. This brief report uses data on vital statistics from a selection of high-income countries, including the United States. The pandemic has been accompanied by a significant drop in crude birth rates beyond that predicted by past trends in 7 out of the 22 countries considered, with particularly strong declines in southern Europe: Italy (−9.1%), Spain (−8.4%), and Portugal (−6.6%). Substantial heterogeneities are, however, observed.

[Marriage and fertility rates of Japanese women according to employment status: An age-period-cohort analysis]

Objectives　This study aimed to examine employment status differences in the marriage and fertility rates of Japanese women via an age-period-cohort (APC) analysis.Methods　We used data collected from 1995 to 2015 in Japan based on the government's "Report of Vital Statistics: Occupational and Industrial Aspects," which recorded the marriage rates of unmarried adults and fertility rates of married adults-according to their employment status. A Bayesian APC analysis was performed to identify changes in marriage and fertility rates based on three effects: age, period, and cohort. Finally, we calculated the marriage and fertility rate ratios between non-employed and employed women for each age group, period, and cohort.Results　The APC analyses showed that the period effect on marriage rates for non-employed women decreased during the periods analyzed, while that for employed women increased from 2005. Meanwhile, the period effect on fertility rates increased regardless of employment status, albeit to a larger degree for employed women. The cohort effect on marriage rates began to decrease from cohorts born in the 1960s for non-employed women, and from cohorts born in the 1970s for employed women. And the degree of the decrease was larger among non-employed women than those employed. Meanwhile, the marriage rate ratio increased from 0.46 (95% CI: 0.21, 0.90) in the cohort born between 1946 and 1950 to 1.00 (95% CI: 0.45, 1.92) in the cohort born between 1991 and 1995. Finally, the fertility rate ratio increased from 0.31 (95% CI: 0.12, 0.69) in the cohort born between 1946 and 1950 to 0.38 (95% CI: 0.14, 1.81) in the cohort born between 1991 and 1995.Conclusion　Employment status differences in the marriage rates of unmarried adults and fertility rates of married adults decreased among younger Japanese cohorts and in recent years. By contrast, there were statistically significant differences in fertility rates of married adults based on employment status, even in cohorts born more recently.

Decrease in American birth rates makes it imperative for the United States to implement state mandated fertility coverage

In recent years, the prevalence of infertility has increased due to delayed childbearing and an increase in the rate of male infertility. Given the high cost of fertility treatment, this option is not valid for families with a low income, and those who can afford it usually choose to have multiple embryo transfer, which has led to an increase in multiple birth rates and an increase in the cost of perinatal care. Due to the expected increase in infertility and decrease in the national live birth rate, the US should set a plan to fund infertility treatment and lead a policy for single embryo transfer. This will offset the decrease in the national birth rates and decrease expenditure on perinatal and neonatal complications resulting from multiple births.

Birth rates after radioactive iodine treatment for differentiated thyroid cancer

Treatment with radioactive iodine (RAI) for differentiated thyroid cancer has been associated with alterations in gonadal function in women, including changes in menstrual function and an earlier age at menopause. Our objective was to evaluate associations between RAI and postdiagnosis live birth rates among thyroid cancer survivors diagnosed at ages 15-39 years. We identified women diagnosed with differentiated thyroid cancer between January 2000 and December 2013 in the North Carolina Central Cancer Registry (CCR). CCR records were linked to state birth certificate files to identify livebirths to thyroid cancer survivors through December 2014. Person-years of follow-up were accrued from 6 months after diagnosis to first birth, 46th birthday, death, or December 31, 2014, whichever came first. Cox proportional hazards regression was used to estimate hazards ratios (HR) and 95% confidence intervals (CI) for first livebirth. Among 2,360 women with a differentiated thyroid cancer diagnosis, 53% received RAI. The cumulative incidence of birth at the end of follow-up (maximum 14.5 years) was 30.0 and 29.3% among those who were and were not treated with RAI, respectively. Overall, first birth rates did not significantly differ between groups (HR = 1.00; 95% CI: 0.82, 1.23). In our observational cohort, treatment with RAI was not associated with a reduced birth rate. Our findings add to the evidence available for counseling thyroid cancer patients with concerns about future fertility.

Relative Age Effect and Academic Timing in American Junior College Baseball

Previous research has shown that older athletes within age groupings are often perceived to be more talented simply due to advanced maturity, leading to biased selection in higher levels of sports competition, now commonly termed relative age effect (RAE). This study's goals were to determine whether (a) RAE influenced the selection of junior college baseball participants and (b) academic timing ( Glamser & Marciani, 1992 ), in which academic status determines age groupings more than strict age guidelines for college sports, influenced the formation of RAE. Participants were 150 junior college baseball players. Our results showed that RAE was only a significant factor, comparing the birth distribution of participants born before and after the midpoint of the participation year, when academic timing was also a factor in determining age groupings. In addition, the birth rate distribution, though not significantly different than expected, was greater only when those participants born during the expected participation year were included. The results of this study indicate that RAE could bear more influence among American student-athletes than was previously reported in that RAE in conjunction with academic timing does influence the selection of collegiate athletes.

"Super Bowl Babies": Do Counties with Super Bowl Winning Teams Experience Increases in Births Nine Months Later?

Following the claim of a highly publicized National Football League (NFL) commercial, we test whether the Super Bowl provides a positive exogenous shock to fertility in counties of winning teams. Using stadium locations to identify teams' counties, we analyze the number of births in counties of both winning and losing teams for ten recent Super Bowls. We also test for state effects and general effects of the NFL playoffs. Overall, our results show no clear pattern of increases in the number of births in winning counties nine months after the Super Bowl. We also do not find that births are affected at the state level or that counties competing in the playoffs are affected. Altogether, these results cast doubt on the NFL's claim that winning cities experience increases in births nine months after the Super Bowl.

Age-specific birth rates in women with epilepsy: a population-based study

OBJECTIVE

The aim of this study was to investigate birth rates and use of hormonal contraception in different age groups among women with epilepsy (WWE) in comparison to women without epilepsy.

MATERIALS AND METHODS

Demographic data and medical information on more than 25,000 pregnant women (40,000 births), representing 95% of all pregnancies in Oppland County, Norway, were registered in the Oppland Perinatal Database in the period 1989-2011. Data were analyzed with respect to epilepsy diagnoses, and 176 women with a validated epilepsy diagnosis (303 pregnancies) were identified. Age-specific birth rates in these women were estimated and compared with age-specific birth rates in women without epilepsy in the same county.

RESULTS

In WWE over 25 years of age, birth rates were significantly lower than in those of the same age group without epilepsy. In women below 20 years of age, birth rates were similar in those with and without epilepsy. The use of hormonal contraceptives prior to pregnancy was lower among WWE under 25 years than in the corresponding age group without epilepsy.

CONCLUSIONS

Health professionals who counsel WWE who are of fertile age should be aware of the strongly reduced birth rates in WWE over 25 years of age, and the lower rates of use of contraceptives among young WWE.

A dynamical model for human population

We analyze a simple, deterministic model of the dynamics of population changes in a bisexual, reproductive system based on marriage. Our model is one of a general class, special cases of which have been previously discussed within the framework of population biology by D. G. Kendall, L. A. Goodman, J. H. Pollard, and others. Here, we extend and complete previous analyses of systems characterized by first-degree homogeneous, unbounded marriage functions, allowing for arbitrary birth and death rates. The dynamics of the model is determined by three coupled first-order, nonlinear differential equations, similar to those used in the description of chemical reactions and of radioactive decay chains. Solutions of the differential equation system are classified according to the associated patterns of birth and death rates of the two sexes, and growth and stability properties are discussed. This preliminary report gives conditions sufficient to insure the existence of a unique, exponential mode of population growth or decay, with a finite ratio of the sexes. We also exhibit other conditions which, in contrast to the standard, linear demographic analysis of Lotka, guarantee that the sex ratio asymptotically becomes infinite. The model manifests a delicate balance between the vital parameters that alerts one to the possibility of selfaggravating distortions of the sex ratio, once a monogamous society's fertility falls below the replacement value.