Those born before week 34 of the pregnancy and weighing less than 1,500 grams most at risk
Scientists have long been aware that premature, low-weight babies face a series of health issues later in life, including higher incidences of cancer, diabetes and attention deficit disorder. Now, a large-scale Israeli study has found that premature babies weighing less than 1,500 grams (3.3 pounds) have a fifty percent lower chance of generating offspring compared to average-weight babies.
“Over the past decade the mortality rate of these babies has not only declined but they are also living longer,” Professor Sorina Grisaru-Granovsky, director of the high-risk pregnancy unit at Israel’s Shaarei Zedek hospital and lead author of the study, explained to The Media Line. “These babies survive into their 20s and 30s and therefore constitute a new high-risk group for cancer, diabetes, and now fertility.”
Using the records of more than 67,000 babies born between 1982 and 1997, the study focused on three groups: babies born before the 34th week of the pregnancy and weighing under 1,500 grams; those birthed between weeks 34 and 37 who weighed between 1,500 grams and 2,500 grams; and normal-weight babies who were born at full-term.
A drop in fertility was found to effect both men and women. In males, it is often accompanied by undescended testicles, which can be corrected by surgery. The study also shows that even mid-weight babies born prematurely are 2.4 times more likely to have premature babies themselves.
Professor Grisaru-Granovsky said that further research needed to be done to determine whether those falling into the first group were less likely to become parents because of incomplete hormonal maturation or due to other serious premature birth-related health issues such blindness and cerebral palsy which reduce the likelihood of reproduction.
She added that other studies in Norway and Denmark found similar results but were not conducted on such a large scale.
Professor Arthur Edelman, a neonatologist and former chief of pediatrics at Shaarei Zedek, said the study adds to a growing body of knowledge about the subject. “Until a few years ago, if a baby was born prematurely and there were no noticeable problems we thought there was no difference between them and full-term babies,” Edelman told The Media Line. “We thought the only factor was complications resulting from premature births, but now we know that is not true.”
He said that if you compare two babies, one born at 40 weeks, and one born at 26 weeks who has spent 14 weeks in an incubator, the premature baby will actually have a better-functioning liver, heart and kidneys. But when it comes to the brain, those born full-term have an advantage.
“It is possible that the premature babies have less hormonal stimulation which is brain-related, or it is possible that the problem is because the eggs were not nurtured for 40 weeks,” Edelman related.
Researchers admit that the study has its limitations, as it only used data derived from birth and did not consider other medical or socioeconomic effects which might contribute to fertility issues later in life. Additionally, the study included individuals still in their 20s, who might not have yet married and therefore could have skewed the findings.
While the study does not offer further insights or recommendations, Grisaru-Granovsky suggested that those born prematurely pay extra attention in their youths to potential fertility issues.