Yes, the older you get, the higher your chances of having a multiple birth, such as twins or triplets. The risk starts at about age 35 years and goes up progressively after that.
The reason for this increase is multiple ovulation. Older women are more likely to release more than one egg in a cycle and therefore have a higher risk of having twins and triplets. (The rate of identical twins does not go up.) The rate of twin deliveries in the US continues to climb, and with it the rate of pre-term deliveries. The increasing rate of twins is one of the reasons that the pre-term deliveries are also increasing.
The rate of twin deliveries rose three percent from 1997 to 1998 and has risen 52 percent since 1980. There are now over 100,000 twin deliveries annually!
In addition to an increased risk of pre-term labor and delivery, older women are also at risk for other complications of pregnancy. High blood pressure, diabetes, premature separation of the placenta from the uterus (placental abruption), and other complications are all more common in older pregnant women. These women are also more likely than younger women to have babies with chromosomal problems, such as Down syndrome.
Despite the increased risk of complications, many older women complete successful pregnancies and have healthy babies. The ability to identify and treat complications of pregnancy gets better each year.
In summary, although the risks to your pregnancy increase as you get older, you still have an excellent chance of having a wonderful baby.