Multiple births are a sociological phenomenon that has double filled Spain with double carts in recent years. In 2014 18.746 babies were born fruit of a multiple pregnancy, representing 2.29% of total births in Spain that year. It is the highest percentage in history in our country and is broken down into 9,493 twin births (2.26%) and 117 births and 2 triple quadruple or more. That is, that 22.9 of every 1,000 births in Spain were more than one baby, above the world average is between 10 and 15 multiple births per 1000 births.
       Since 1983 assisted reproductive technologies were introduced in Spain, twin pregnancies have tripled, that is to say, increased by 287%. Helped by the fact that increasingly have children later, Spain is the second European country with the highest percentage of mothers over 35 years, 29.5%, so it is logical that is increasingly employing such techniques . In addition, between 25 and 35 the probability of becoming pregnant with twins naturally is multiplied by four. Other determinants are race – black is the most highly prevalence, family history – there is a genetic component inherited the twins – and body mass index – the fatter and taller women have higher propensity.

resource: key4communications