Twinning Rates in Uruguay Between 1999 and 2015: Association with Socioeconomic and Demographic Factors

Abstract

Twinning is rare among humans, but there is much variability among populations. Several studies show that certain demographic and socioeconomic factors, such as maternal age, mother’s educational level and income, influence twinning rate. There is no background of analytical studies of twins in Uruguay. To the best of our knowledge, this is the first study that has focused on describing and analyzing Uruguayan twinning rates over a period of 17 years (1999–2015). The birth data were collected from the website of Uruguay’s Ministry of Public Health. Economic data were obtained from Uruguay’s Instituto Nacional de Estadísti’s website for the period 2001–2013, since these variables are defined specifically for that period of time. The statistical software R (The R Project for Statistical Computing) was used. The twinning rate varied from 8.51 to 13 in the studied period. Montevideo has the highest median and the smallest variability in comparison with the other departments. In Uruguay (1999–2015), the highest twinning rate (28.94%) was observed in women aged 45 and older. The analysis also showed a relationship between twin birth rates and the mother’s educational level. In three regions of the country (West, Center and East), twin births show a random pattern but in the other two (North and Metropolitan), there is an increasing trend in the number of twins over time. In conclusion, this study recognizes social, economic and demographic factors that influence in the rate of twin births in Uruguay.

Twin studies in behavioral and health research: current status, prospects and aplications

“…The mother's age is a relevant variable in the TR, as well as certain factors related to her economic status, educational level and the use of ARTs. In conclusion, this study found social, economic and demographic factors significantly associated with the rate of twin births in Uruguay (Gómez et al, 2019). Data from national birth registries do not specify zygosity.…”

Trends in Dizygotic and Monozygotic Spontaneous Twin Births During the Period 2007–2017 in Lombardy, Northern Italy: A Population-Based Study

“…Norway, Denmark and Sweden) observed a decline in the twinning rate from the early 2000s (data estimated by published figures) and suggested that the improved treatment fertility techniques may avoid multiple pregnancies (Fellman, 2016). Instead, in South America from 2000 to 2014, the twinning rate increased from about 8.5 per 1000 pregnancies to 10.2 per 1000 in Brazil (Otta et al, 2016) and 12.9 in Uruguay (Gomez et al, 2019), where probably the access to the fertility procedures had widened in recent years.…”

The University of São Paulo Twin Panel: Current Status and Prospects for Brazilian Twin Studies in Behavioral Research

“…We took part in another population study in which the birth rate of Uruguay was investigated for the first time, over the years 1999-2015, from Uruguay's Ministry of Public Health database, in partnership with Painel USP de Gêmeos (Gómez et al, 2019). We expect that other countries in Latin America will feel encouraged to conduct similar population studies, since these data are still lacking.…”