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. 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).
About 60 percent of twins, more than 90 percent of triplets, and virtually all quadruplets and higher-order multiples are born premature. The length of pregnancy decreases with each additional baby. On average, most singleton pregnancies last 39 weeks; for twins, 35 weeks; for triplets, 32 weeks; and for quadruplets, 29 weeks.
More than half of twins and almost all higher-order multiples are born with low birthweight (LBW), less than 5½ pounds or 2,500 grams. LBW can result from premature birth and/or poor fetal growth. Both are common in multiple pregnancies.
LBW babies, especially those born before about 32 weeks gestation and/or weighing less than 3 1/3 pounds (1,500 grams), are at increased risk of health problems in the newborn period as well as lasting disabilities, such as mental retardation, cerebral palsy, and vision and hearing loss. While advances in caring for very small infants has brightened the outlook for these tiny babies, chances remain slim that all infants in a set of sextuplets or more will survive and thrive.
Preeclampsia and diabetes in the mother are two conditions that, for the safety of the mother and baby, can lead to an early delivery. Women expecting twins are more than twice as likely as women with a singleton pregnancy to develop preeclampsia. Gestational diabetes can cause the baby to grow especially large, increasing the risk of injuries to mother and baby during vaginal birth and making cesarean delivery more likely. Babies born to women with gestational diabetes also may have breathing and other problems during the newborn period.
Have you or someone in your family had twins or triplets? Were they in the NICU?