Artificial conception methods such as ART, IVF, and ICSI have increased throughout most Western nations in recent years. It’s currently estimated that over 6-million ART-conceived children were born in the year 2016 alone. Of them, 80,000 were born in the Netherlands.
During each phase of an ART treatment process, there are different techniques used. This includes the stimulation of multiple follicles are part of the oocyte retrieval and sperm preparation process. Following this embryo culture, sperm cryopreservation and the preservations of oocytes and embryos serve as important steps leading up to embryo transfer. The process is significantly different from natural conception.
ART occurs in the same timeframe as epigenetic programming. This means that during the first days after conception, the pre-implanted embryo can be very sensitive to environmental factors that were generated during embryo culture. This may further alter fetal development, with repercussions that are both prenatal as well as postnatal. At the same time differences in the methylation of multiple genes have been found in things such as cord blood as well as placenta samples that were taken from children who were conceived by IVF as opposed to in vivo. It’s also worth noting that altered epigenetic patterns have also been found in embryos that were derived from animals after the ART process. At the same time, there have been a few studies of ART-conceived children that found an unexpectedly high incidence of rare cancer syndromes. This includes things like Beckwith–Wiedemann syndrome as well as Angelman syndrome. Furthermore, a systematic meta-analysis conducted in 2013 found an increased cancer risk in children who were conceived by fertility treatments. Yet this study also found that it isn’t fully clear whether these factors, underlying subfertility, or the ART treatment process itself is a primary factor. Continuing research was required, which included several cohort studies, which also reported comprehensive results for the overall risk of cancer. In two of these studies, increased overall cancer risk was found in the offspring of women with long-term fertility problems. It’s still worth noting that while each study found an increased risk for specific cancer types, the findings were inconsistent from one study to the next. The studies had relatively short follow-up periods as well as other limitations including a small number of cases and potential restrictions to the general population comparison group. This made it difficult to preclude firm conclusions. Therefore, the evaluated cancer risk in children and young adults conceived by ART in the Dutch nationwide OMEGA-offspring cohort is potentially dubious.
In 1995 a Nation-wide research study based in the Netherlands examined the cancer risk amongst women who had received ovarian stimulation as part of the ART process. It identified over 30,000 women who received one or more ART treatments during a span of time between 1983 and the year 2000.
With 70% of these cases, the conception method was self-evident thanks to the complete information derived from the specific pregnancy provided by the mother’s questionnaire or a case where the child could only have been conceived by ART.
At the end of this process, six mutually exclusive exposure categories were generated.
- Children conceived by IVF/ICSI/cryopreservation of embryos, ART-conceived.
- Children conceived by FDs, with/without intrauterine insemination, but not by ART.
- Children who naturally conceived.
- Children who were naturally conceived by FDs, but not by ART.
- Adopted children.
- Children with an unknown or unclear method of conception
The net results of the study found that 24,269 children were conceived by ART, another 4,181 by fertility drugs, and with/without intrauterine insemination. There were also 13,761 natural conceptions as well as 5,479 which were conceived naturally or by non-ART fertility drugs. When this was compared to the general Dutch population, overall cancer risk was not increased in the entire OMEGA-offspring cohort. It’s also worth noting that there was a longer follow-up in the risk of cancer compared with the general population which did not increase in ART-conceived children between the ages of 15 to 19 years. A minimal increased risk was observed in children who were conceived by ICSI than compared with the general population of the Netherlands.
This large-scale study which included 21-years of follow-up demonstrated that the overall cancer risk for ART-conceived children is not higher than the general population.
Photo: NYFI
Based on Oxford Academic
