For children conceived using assisted reproductive technology (ART), early weight differences do not appear to persist into puberty, researchers report.
With Dr. Ahmed Elhakeem of the University of Bristol, UK, and colleagues, those conceived naturally, those conceived through ART tend to be shorter and lighter in early childhood.
However, as shown in their study in JAMA Network Open, the weight difference in children receiving ART was only in infants Periods are evident and then fade away throughout childhood. More specifically, adjusted mean weight differences were no longer significant at age 14:
- 17 to 23 months: -0.16 SD units (95% CI -0.22 to -0.09)
- 14 to 17 years: -0.02 SD units (95% CI -0.15 to 0.12)(*
“The results do not appear to be related to multiple births and are at least partially influenced by birth weight and gestational age, especially in young,” the researchers noted.
They added that the findings should be “reassuring as differences in early growth were small, although more follow-up and more research in older adults is needed to investigate this Likely to be more obese in adulthood.”
Not all children conceived through ART tend to be smaller babies, however. Elhakeem’s group found that this smaller size was only seen in those who conceived through fresh (not frozen) embryo transfers versus natural conception. The weight difference between fresh embryo transfer and natural conception was -0.14 (95% CI -0.20 to -0.07) SD units at age 4 to 5 years, and the weight difference between frozen embryo transfer and frozen embryo transfer was 0.00 (95% CI -0.15 to -0.15) 0.15) SD units for natural conception.
This is not surprising, as Elhakeem’s group says the finding is consistent with previous research on the subject of lower birth weight in offspring conceived via fresh embryo transfer Birth weight and large-for-gestational age of offspring conceived by frozen-thawed embryo transfer compared to offspring conceived by fresh embryo transfer.
Weight differences in children conceived via fresh-embryo ART were also not limited to body weight, these early life size researchers reported. These children also tended to have smaller waist circumferences, body fat percentage and fat mass index. Although, like weight, these differences gradually diminished during adolescence.
“There is little evidence that the difference is due to subfertility of the parents, when we compare offspring conceived through ART with those who conceived after 12 months of trying [natural conception] ] and conceived within a shorter period of time after the attempt began,” Elhakeem’s team noted.
A total of 26 study cohorts were included in the meta-analysis, including data on 158,066 offspring – 4,329 of whom were conceived by ART. Cohorts were drawn from Europe, Asia Pacific and North America and consisted mainly of children born after 2002.
Kristen Monaco is a staff writer focusing on endocrinology, psychiatry and nephrology news. She works out of the New York City office and has been with the company since 2015.
The study was funded by the European Research Council, the Medical Research Council, the British Heart Foundation and the Bristol National Institutes of Health Biomedical Research Centre under the EU Horizon 2020 research and innovation programme.
Elhakeem made no disclosures; other co-authors reported several disclosures, including some relationships with commercial entities.