Infertility treatment affects a child’s growth pattern, but not long

Children born as a result of fertility treatment have different growth patterns than naturally pregnant children, but by the age of 17, the height, weight, and body mass index (BMI) are higher, according to a study published today. Will be the same (Wednesday) Human reproduction [1]..

A study of 81,461 children in the Norwegian Mother, Father and Child Cohort Study (MoBa) and 544,113 teenagers screened for military service and registered in the military health registry was supported by reproductive technology ( ART) Researchers say.

ART is known to be associated with low birth weight, but it is not clear how long the growth difference will persist in childhood. Further studies were needed to determine whether growth patterns could be affected by various fertility treatments or underlying subfertility in naturally pregnant parents.

Dr. Maria Magnus, a researcher at the Fertilizer and Health Center of the Norwegian Institute for Public Health (Oslo, Norway), and her colleagues found in a MoBa study of 79,740 spontaneous pregnancies and 1,721 ART children by age seven I examined the data. Among the naturally pregnant children were 5,279 born to infertile parents who took more than 12 months to become pregnant. Among the children of ART, 1,073 were born from fresh embryos and 179 were born from frozen embryos.

They found that children born after ART had an average birth weight of 3,495 g and an average length of 50.2 cm, while naturally pregnant children weighed 3,608 g and 50.5 cm. However, ART children grew faster in the first 18 months, and after the age of one they were slightly longer and heavier than naturally born children. This difference lasted until the age of seven. Children born to infertile parents are not as small as ART children, but they are smaller at birth and show similar growth patterns to ART children. Children born from fresh embryos were smaller than naturally born children, whereas children born from frozen embryos resembled naturally born children.

The researchers then examined 17-year-old data in the military health registry, including information on fertility from the national birth registry and self-reported height, weight, and BMI at age 17. .. Differences between ART and spontaneously pregnant teenagers, or those born as a result of frozen or fresh embryo transfer.

Dr. Magnus said: “The fact that there was no difference in height, weight, or BMI between ART and offspring naturally pregnant at age 17 is encouraging. Our study found growth patterns in children pregnant after birth and after freezing. The first study to show a clear difference. Assisted reproductive technology up to school age. Further studies are needed to assess what underlies these differences and are observed among ART children in the first year of life. Longer follow-up is needed to assess whether accelerated growth affects later health.

Other studies suggest that rapid childhood growth can adversely affect the heart, blood vessels, and metabolism. One study shows that rapid weight gain in children born as a result of fertility treatment is associated with increased blood pressure between the ages of 8 and 18, while another study shows type 1 diabetes. Has been shown to be at high risk.

“As more and more ART offspring enter adulthood, future studies need to assess potential long-term health effects,” said Dr. Magnus.

Possible explanations for why ART children are small at birth include the effects of hormone therapy that stimulates maternal ovulation, or the effects of media in which embryos are stored in the laboratory. Factors involved in parents’ fertility problems may also play a role, supported by the discovery that naturally pregnant babies born to infertile parents were small.

The limits of the study depended on the fact that there may be selection bias due to voluntary participation in MoBa studies, and that researchers relied on self-reported measurements of height and weight of teenagers in the military health registry. Includes the fact. The strengths of this study are the inclusion of large numbers of children and teens and information on the low conception rate of parents in the MoBa study.

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[1] “Children’s Growth Invented by ART”, Maria C. Magnus et al. Human reproduction journal. doi: 10.1093 / humrep / deab007

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