Multiples: twins, triplets and beyond
When a woman is carrying one baby (fetus), it is called a singleton pregnancy. When she is carrying two or more babies, it is called a multiple pregnancy.
In the past 2 decades, the rate of multiple births in the United States jumped dramatically. The rate of twin births increased by 70 percent between 1980 and 2004, and the rate of higher-order multiples (triplets or more) increased four-fold between 1980 and 1998 (1).
However, the rapid rise in multiple birth rates may be ending. In 2005 and 2006, the rate of twin births remained stable (1). The rate of higher-order multiple births has declined 21 percent since its peak in 1998 (1).
Today, more than 3 percent of babies in this country are born in sets of two, three or more; about 95 percent of these multiple births are twins (1). The high number of multiple pregnancies is a concern because women who are expecting more than one baby are at increased risk of certain pregnancy complications, including premature birth (before 37 completed weeks of pregnancy). Premature babies are at risk of serious health problems during the newborn period, as well as lasting disabilities and death.
Some of the complications associated with multiple pregnancy can be minimized or prevented when they are diagnosed early. There are a number of steps a pregnant woman and her health care provider can take to help improve the chances that her babies will be born healthy.
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