Healthcare

Significant statistically from population-based study as an outgrowth of a previous study by same Swedish researcher showed that the children born after in vitro fertilization (IVF) are ‘moderately’ increased the risk of developing childhood cancer.

26,692 children born after IVF compared with control group of 2.4 million children not conceived by IVF between 1982 to 2005 investigated by the researchers.
From their identification, the risk of total cancer estimated 1.42 from 53 cases identified (38 cases were expected) in children who were born after IVF.

Although the investigator don’t believe the link between IVF and that risk, Bengt Källén, MD, PhD, the lead author of the study from the Tornblad Institute of the University of Lund in Sweden, said, “this is probably not attributable to the IVF procedure itself but could be an effect of confounding from unidentified characteristics of women who undergo IVF or could act via the widely known increased risks for neonatal complication.”
However, Källén said, “it should be stressed that the individual risk for a child who is born after IVF to develop childhood cancer is low.”

The authors point out that the increased risk for perinatal complications from IVF births include congenital malformations.

From the study results among 53 cancer cases that found in the study , the researchers found;
- 18 infants had hematologic neoplasms (12.3 expected), 15 of which were acute lymphoblastic leukemia,
- 15 infants had central nervous system neoplasms (8.1 expected), 7 of which were astrocytomas,
- 2 infants had malignant retinal tumors (retinoblastoma) (1.25 expected),
- 6 infants had Langerhans cell histiocytosis (1 expected).

The odds ratio after adjustment for year of birth for childhood cancer among infant who were born after IVF was 1.42.

Due to the Langerhans cell histocytosis classified as a cancer and debatable for “is it a malignant neoplastic disease or a reactive process?”, the authors write, “little is known about the epidemiology of Langerhans histiocytosis.”
Therefore, they performed an analysis of the total cancer risk that excluded the children with histiocytosis and found that the odds ratio went down to 1.34, but remained statistically significant.

There is a question for what’s driving the increasing risk of childhood cancer for infant who was born after IVF.

The investigators observed that in the study, the mothers of children born after IVF differed in many ways from the 2.4 million other women who gave birth such as there was a high percentage of first parity, maternal age was higher, more had a high body mass index, fewer smoked, and fewer were born outside Sweden.

The authors report that neither the differences between the 2 sets of mothers nor adjustment for these differences had any impact on the estimated risk, but neonatal characteristic did affect cancer risk.

There was an increased risk for cancer associated with preterm birth before week 37, a birth weight of 4500 g of higher, and a low Apgar score.

The authors write, “neonatal factors could act as intermediaries between the IVF procedure and cancer development.”

They also note that, in various studies, 2 neonatal factors have shown a “relatively constant association” with an increased childhood cancer risk: high birth weight and neonatal asphyxia.
In this study, both factors was seen. Neonatal asphyxia or oxygen treatment was indicated in the study by a low Apgar score.
However, the authors write that in this study, multiple births which are a common complication in IVF pregnancies didn’t seem to factor into the cancer risk.