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How likely are multiples to be born premature?


Photo courtesy Wikipedia Commons
Pre-term birth is a major concern for women pregnant with multiples.  The March of Dimes estimates that 60% of twins, 90% of triplets, and essentially all quadruplets and higher order multiples are born early and an informal survey of parents done by the multiples guide at shows 64% report their babies were premature.  The March of Dimes cites the average pregnancy lengths below.
  • Singleton: 39 weeks
  • Twins: 35 weeks
  • Triplets: 32 weeks
  • Quadruplets: 29 weeks
Medical professionals consider 37 to 40 weeks of gestation to be full term, though most of the rest of us just think of it as nine months.  Any birth before 37 weeks is considered pre-term and any birth before 32 weeks is considered very pre-term.  The dangers of a pre-term birth are pretty evident.  The fetus spends every bit of its time in the womb preparing for independent life and ending that preparation early usually results in a baby that needs medical help. 
The bare minimum gestation time that a baby needs in order to survive outside the womb is generally considered to be about 24 weeks, but a baby born that early would need a lot of medical intervention in order to survive.  Some of the more common problems for   The lungs are generally the last to develop, so many babies born very prematurely will spend some time on a ventilator.  The fetus also gains a lot of its excess weight toward the end of gestation, which is why premature babies always look so emaciated.  You can get more details from the March of Dimes.
Mother nature does try to compensate for the shorter gestation time of multiples.  Gestational development of multiples often speeds up in the third trimester so that the babies might have a better chance after birth.  Medical science also has various methods to slow things down if a woman's body starts to prepare for birth.  The most common is simply prescribing bed rest or limited activity for the expecting mother, but drug treatments are used as well.  In cases where a it's likely a baby will be born before 34 weeks, the provider may recommend an injection of corticosteroids for the mother in an effort to speed up fetal lung development.
Premature birth in the U.S. has been on the rise in the last twenty years, which isn't what you would expect given the advance of medical science.  In 2006, 12.8% of all babies were born before 37 weeks, with 3.7% born before 34 weeks.  The rising rate is thought to be mostly attributable to the rising rate of multiple births.  In singleton births only, 11% are premature.  Some also attribute this rise in premature births to a more pronounced tendency for obstetric professionals to perform Cesarean sections rather than trying to prolong at-risk pregnancies.
For a more local perspective, 2007 birth data shows a pre-mature birth rate of 11.9% in Davidson County (Nashville).  Shelby County (Memphis) had a rate of 12.6%, Knox County (Knoxville) was 12.4%, and Hamilton County (Chattanooga) was 14.6%.
It isn't all gloom and doom though.  Being pregnant with multiples isn't an automatic ticket to premature labor and the host of other things more likely to go wrong for multiples pregnancies.  The blog Looky Daddy! has an excellent post for those who want to forget the gloomy statistics.  Looky Daddy! is written by a father of multiples, but his wife commandeered the blog for a day so she could collect inspirational stories about pregnancies free of serious problems and births with healthy multiples.

Coming up next week........ parents give advice on coping when your child is in the NICU.