Higher risk of long-term developmental problems in moderately preterm infants

Children born 4-8 weeks prematurely have a higher risk of developmental problems than previously presumed. This is one of the findings in the Pinkeltje study, set up by UMCG paediatrician and neonatologist Jorien Kerstjens. ‘Some seven percent of all children in the Netherlands are born prematurely and the majority of them (70-85%) fall into this category,’ says Kerstjens. ‘It is a “forgotten” group. Unlike children born more than eight weeks prematurely (the “real” premature infants), paediatrics does not provide follow-up monitoring during their development.’ In view of the fact that 35% of brain development takes place in the final phase of pregnancy, Kerstjens is arguing for greater awareness of the risk of developmental problems in moderately preterm-born children. She will be awarded a PhD by the University of Groningen on 13 May 2013.

Kerstjens compared the development of children born moderately prematurely with that of children born full term and very prematurely (pregnancy of less than 32 weeks). At four years of age, she found developmental problems in 8.3% of the moderately preterm-born children, which is double the percentage found in children born full term. Developmental problems were evident in 14.9% of the seriously preterm-born children. By the age of seven, the moderately preterm-born children were scoring lower than children born full term for IQ, the development of visual-spatial skills (such as doing jigsaws), attention span and selective focusing on main issues. ‘Up until now, it was generally assumed that moderately preterm-born children would develop normally, but my research shows that some of these children show clear signs of long-term developmental problems’, says Kerstjens.

Exponential

The more prematurely infants are born, the higher the risk of developmental problems, concludes Kerstjens. ‘We think this is because the most important part of brain development takes place in the third trimester of pregnancy. Many premature infants have also experienced other problems relating to the placenta; they are put into incubators immediately after birth, are fed differently and exposed to different stimuli than if they had been carried to full term. This causes their brains to develop differently from children born full term.’ Kerstjens would like to see more attention paid to these risks when deciding whether or not to deliver an infant before term.

Factors

A number of well-known factors increase the risks of premature labour and developmental problems in moderately preterm-born children. Kerstjens cites smoking during pregnancy and obesity on the part of the mother. ‘Multiple pregnancies also tend to be shorter. Fertility treatment such as IVF often leads to multiple births. Indirectly, my research seems to be advising women not to wait too long before getting pregnant,’ says Kerstjens.

Social importance

According to Kerstjens, we are currently putting a lot of effort into monitoring and helping children born more than eight weeks prematurely. ‘This is obviously important, but we should be doing more for the group of moderately preterm-born children too. The social importance of monitoring and helping this group should not be underestimated. It’s actually more important than helping the group of very preterm-born children.’ In absolute terms, the group of moderately preterm-born 4-year-olds with retarded development in the Netherlands is probably twice as large as the group of more seriously preterm-born 4-year-olds with developmental problems. Kerstjens thinks that helping these children during the first four years of their lives may improve their opportunities in the future. She is also predicting more attention world-wide for moderately preterm-born children.

Curriculum Vitae

Jorien Kerstjens (Zwijndrecht, 1962) studied medicine at the University of Groningen. She trained as a paediatrician, worked as a general paediatrician for 10 years, and was then also trained as neonatologist in the Beatrix Children’s Hospital in the UMCG in Groningen and the Isala Klinieken in Zwolle. This unique combination aroused her interest in the development of children born prematurely and prompted her to set up the Pinkeltje study, which examines various aspects of the development of moderately or very preterm-born children. The Pinkeltje study is funded by the Beatrix Children’s Hospital UMCG, the Cornelia Foundation, the A. Bulk Youth Healthcare Research Fund, the Netherlands Brain Foundation, FrieslandCampina, Friso Nederland, Abbott and Pfizer Europe. Kerstjens conducted her research in the Neonatology Department of the UMCG under the supervision of Prof. A.F. Bos, Prof. S.A. Reijneveld, and Dr A.F. de Winter from the Health Sciences Department. Her thesis is entitled ‘Development of moderately preterm-born children.’