Twinning rate in a sample from a Brazilian hospital with a high standard of reproductive care

Abstract

CONTEXT: Epidemiological studies on twin births have been motivated mostly by the positive correlation between twinning rate and human fertility, prematurity, low birth weight, increased risk of infant death and long term risk for morbidity. OBJECTIVE: This paper intends to estimate the incidence of multiple births in a private hospital in Brazil with a high standard of reproductive care, and to evaluate the effects of maternal age, gestation order and assisted fertilization on twinning rate. DESIGN: Retrospective analysis. SETTING: First-class tertiary private hospital, São Paulo, Brazil. PARTICIPANTS: The multiple birth rate was investigated among 7,997 deliveries from 1995 to 1998, including 7,786 singletons, 193 twins, 17 triplets and one quadruplet. RESULTS: The rates per 1,000 dizygotic and monozygotic pairs and for triplets were estimated as 19.51, 4.50 and 2.13, respectively. The dizygotic and triplet rates were the highest observed in Brazil up to the present day. The twinning rate among primigravidae older than 30 years was very high (45.02 per 1,000) and was due to a disproportionately high frequency of dizygotic pairs. The triplet rate was also very high among the mothers of this age group (5.71 per 1,000). These facts are strong indicators that these women were the ones most frequently submitted to assisted reproductive techniques. The mean maternal age of the studied population was about six years higher than that estimated for mothers in the general population of southeastern Brazil. Primigravidae aged under 30 years as well as multigravidae showed similar twinning rates, which were almost 20 per 1,000. Among the deliveries of multigravidae older than 30 years, an unusually high frequency of monozygotic twins was observed (7.04 per 1,000), probably as a consequence of the residual effect of long-term use of oral contraceptives. CONCLUSIONS: The dizygotic twinning rate increased from 13.51 to 28.98 per 1,000 over the four years studied, with the twinning rate for primigravidae over 30 years old in 1998 being twice that observed in 1995. The mean maternal age was also high during this period, but the extremely high increase in twinning rate observed cannot be attributed solely to this variable. Assisted fertilization seems to be the most probable cause of this unusually high twinning rate.

Perfil das patologias prevalentes na gestação de alto risco em uma maternidade escola de Maceió, Alagoas, Brasil

“…23 Apesar de alguns estudos retrospectivos sugerirem que a cesárea é benéfica para o prematuro extremo em apresentação cefálica, não há evidências científicas consistentes de que a prática da cesárea melhore a sobrevida ou diminua a morbidade neonatal. 24 Levando-se em consideração o agrupamento das variáveis (desvio quanto ao crescimento uterino e volume de líquido amniótico, gemelaridade) não foi possível atribuir as prevalências encontradas a cada uma isoladamente, porém a explicação para alguns dos achados pode ser sugerida pelo perfil epidemiológico conhecido de uma delas, de modo que a maior quantidade de gestantes (50%) com idades entre 31 e 40 anos pode ser justificada pelos casos de gravidez múltipla que costumam acometer essa faixa etária, 25,26 assim como a maior ocorrência de cesáreas (80,4%) a qual tem risco aumentado em 8,3 vezes segundo Cabral et al. 27 Na comparação da prevalência de pré-eclâmpsia e eclâmpsia com faixa etária, número de gestações e tempo de gestação, esta patologia esteve mais presente nas gestantes entre 20 e 30 anos (41,3%), primigestas (72,2%), que evoluíram com parto a termo (63,9%).…”

Twinning rate trend in a population sample from the city of São Paulo, Brazil

“…Among people of the middle and upper socioeconomic classes, the access to assisted reproduction techniques is growing, and this is correlated with multiple pregnancies (Steegers-Theunissen et al, 1998;Keith et al, 2000;Colletto et al, 2001). So, we cannot discard the possibility of this fact contributing to the rise of the incidence of dizygotic twin and triplet births.…”

“…The dizygotic twinning rate is positively correlated with maternal age and parity (Allen and Parisi, 1990;Beiguelman et al, 1996), as well as with assisted reproduction (Keith et al, 2000;Kiely and Kiely, 2001;Colletto et al, 2001). Prior to the widespread use of assisted reproduction techniques, a decrease in the dizygotic twinning rate had been observed in most of the urban populations studied (Beiguelman et al, 1996).…”

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

“…Only a few studies have investigated the twinning rates in Brazil, showing highly divergent results, 2 that is, between 4.7 and 29.0‰ (Colletto, 2003;Colletto & Rosario, 2004;Colletto et al, 2001;2003;Geraldo et al, 2008, for details see, Table 1). These studies were conducted in only a few hospitals in the cities of São Paulo and Pelotas (located in southeast and south of Brazil, respectively).…”