Twinning and Multiple Birth Rates According to Maternal Age in the City of São Paulo, Brazil: 2003–2014

Abstract

The present study investigates the twinning rates in the city of São Paulo, Brazil, during the years 2003-2014. The data were drawn from the Brazilian Health Department database of Sistema de Informações de Nascidos Vivos de São Paulo-SINASC (Live Births Information System of São Paulo). In general, more information is available on the incidence of twinning in developed countries than in developing ones. A total of 24,589 twin deliveries and 736 multiple deliveries were registered in 140 hospitals of São Paulo out of a total of 2,056,016 deliveries during the studied time period. The overall average rates of singleton, twin, and multiple births per 1,000 maternities (‰) were 987.43, 11.96 (dizygotic (DZ) rate was 7.15 and monozygotic (MZ) 4.42), and 0.36, respectively. We further regressed maternal age and historical time period on percentage of singleton, twin, and multiple birth rates. Our results indicated that maternal age strongly positively predicted twin and multiple birth rates, and negatively predicted singleton birth rates. The historical time period also positively, although weakly, predicted twin birth rates, and had no effect on singleton or multiple birth rates. Further, after applying Weinberg's differential method, we computed regressions separately for the estimated frequencies of DZ and MZ twin rates. DZ twinning was strongly positively predicted by maternal age and, to a smaller degree, by time period, while MZ twinning increased marginally only with higher maternal age. Factors such as increasing body mass index or air pollution can lead to the slight historical increase in DZ twinning rates. Importantly, consistent with previous cross-cultural and historical research, our results support the existence of an age-dependent physiological mechanism that leads to a strong increase in twinning and multiple births, but not singleton births, among mothers of higher age categories. From the ultimate perspective, twinning and multiple births in later age can lead to higher individual reproductive success near the end of the reproductive career of the mother.

Twin Births In The Pelotas (Brazil) 2004 And 2015 Birth Cohorts 

“…There was no difference in twinning rates between the two cohorts, but the rate in 2015 (1.4%) was higher than in the Brazilian state where Pelotas is located (Rio Grande do Sul) (1.2%) (p = 0.04) and in Brazil as a whole (1.13%) (p = 0.002) from 2011 to 2014. (4) This nding is consistent with the fact that the prevalence of some maternal factors associated with the occurrence of twin pregnancies, such as higher age and obesity, (20,31) increased in Pelotas in the last three decades. The proportion of mothers 35 years or older increased from 9.9% in 1982 to 11.0%, 13.3%, and 14.7% in 1993, 2004, and 2015, respectively.…”

“…(15)(16)(17)(18) There are still few studies on the epidemiology of twin pregnancies and twin births in Brazil. (4,8,(19)(20)(21)(22) Thus, based on data from the 2004 and 2015 Pelotas Birth Cohorts, this study aimed to describe the prevalence of multiple pregnancies according to maternal characteristics and to compare rst-and second-born twins from the same cohort to each other and to newborns from singleton pregnancies, according to the incidence of unfavorable perinatal outcomes and infant mortality rate (IMR). The use of two populationbased birth cohorts from the same city, eleven years apart, with data collected for each twin separately at the time of birth, allows to estimate change in twin births prevalence and to assess difference of risk according to birth order.…”

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

“…Considering the whole city of São Paulo (Otta et al, 2016), the overall average rates of twin and multiple births per 1000 maternities (%) were 11.96 (7.15 DZ and 4.42 MZ) and 0.36, respectively. Over the whole time period considered, we found that the twin birth rate increased 30.8% from 2003 (10.19%) to 2014 (13.33%).…”

Epigenetic Consequences of Hormonal Interactions between Opposite-sex Twin Fetuses

“…The incidence of spontaneous dizygotic twinning is between 1% and 4%[1], which is increasing due to advanced maternal ages and the application of assisted reproductive technologies[2, 3]. Approximately 40% of twins are opposite-sex (OS)[4].…”