Every Week Counts – in the Womb

Extremely premature babies survive with less disability for each extra week before birth

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) A single week out of the year may not seem like a big deal - unless you're a tiny human waiting to greet the world. For preemies, every week counts.

That's the conclusion of a study comparing toddlers who were born extremely premature in 1995 or in 2006.

Each week later the kids were born, the lower their rate of disabilities were. The other good news was that severe disabilities among extreme preemies have decreased from 1995 to 2006.

"Attend all prenatal appointments."

The study, led by Tamanna Moore, a research associate in the Academic Neonatology unit at the UCL Institute for Women's Health in London, focused on how well 3-year-old children were doing if they had been born before the 27th week of pregnancy.

The researchers compared 584 children who had been born between the 22nd and 25th week of pregnancy in 2006 to 260 children born during the same pregnancy weeks in 1995. Specifically, the researchers looked at how many children survived to age 3 and what disabilities or developmental differences they had.

Among the 2006 babies, 13 percent had a severe disability and 12 percent had a moderate disability. Cerebral palsy affected 14 percent of these children.

The earlier the children were born during their mother's pregnancy, the more likely it was that they would have brain developmental difficulties. While 45 percent of the children born at 22 to 23 weeks of pregnancy had neurodevelopmental disabilities, only 20 percent of the babies born at 26 weeks had these problems.

Similarly, the children's IQ was higher for each additional week of pregnancy when they were born. The average IQ of the children born at 22 to 23 weeks was 80.

The children's average IQ was 86 if they were born at 24 weeks, 88 if they were born at 25 weeks and 91 if they were born at 26 weeks. An average IQ for the general population is 100.

The number of babies who survived extreme prematurity with a severe disability was nearly the same in 1995 and 2006: 18 percent in 1995 and 19 percent in 2006.

But there was also an increase in the extremely premature babies who were admitted to neonatal care and survived without any disability. Only 23 percent of the extremely premature children born in 1995 had no disability, which rose to 34 percent for children born in 2006. One reason may be lower rates of moderate disability.

The researchers concluded that the outcomes for babies overall improve for each additional week they remain in the womb.

The study was published December 4 in the journal BMJ. The research was funded by the Medical Research Council. The authors declare no conflicts of interest.

Reviewed by: 
Review Date: 
December 4, 2012
Last Updated:
December 5, 2012