At the present time, twins in the United States are born approximately twice as often than 20-40 years ago. The data was received from the centers for the control and elimination of diseases in Atlanta, in the state of Georgia.
The report states that in 2009 more than 137 thousand twins were born in the United States. That is, for every 30 genera there was one such case. In 1980, only 68 thousand newborn twins were recorded. Joyce Martin, one of the researchers of this phenomenon, said that the growth of the appearance of twins is observed in all age groups and in all states.
“The main reason for this trend can be called excellent successes of modern medicine in the treatment of infertility,” ITAR-TASS reports. Researchers note that such a pregnancy is relatively difficult, and the twins are born a little earlier. Also their weight is less than the weight of the average newborn. Despite this, most of the births with twins are fine.
It is believed that nationality, age and heredity of the future mother play a large role in multiple pregnancy. According to research, twins most often be born in African American diasporas. The probability of the appearance of such newborns increases with an increase in the age of the expectant mother.