The Unknown Factor
Ethnicity can affect IVF success rates
For many couples who struggle with infertility, artificial reproductive techniques (ART) like In-Vitro Fertilisation (IVF) and Intracytoplasmic Sperm Injection (ICSI) are their only options in the hopes of conception and starting a family of their own. However, if you are considering IVF, it is important for you to learn about IVF success factors that can either boost or hinder your chances at pregnancy.
The main factors that may impact IVF success are age, especially of the mother; a history of previous pregnancies or miscarriage with the same or different partner; the type of fertility problem; lifestyle habits; the use of donor eggs and the fertility clinic chosen. However, several studies have contributed another factor for IVF success – a woman’s ethnicity.
In an observational cohort study conducted by the Nottingham University Research and Treatment Unit in Reproduction (NURTURE), UK, it was found that live birth rates following IVF treatment was significantly lower in Asian and Black women, as compared with white European women.
The study involved 1517 women, of which 1291 were white Europeans and 226 belonged to ethnic minorities. All these women underwent their first cycle of assisted reproductive technology between 2006 and 2011.
Despite sharing favourable chances of conceiving, such as the quality of their egg reserves, only 35% of Asian and Black women successfully conceived and gave birth after IVF, as compared with 44% of white women who were treated at the same clinic during that period.
The researchers at NURTURE are unsure why this is, but suggest that it could be down to genetics, as well as social and environmental factors. According to lead researcher, Dr Walid Maalouf, “Further research into genetic background as a potential determinant of IVF outcome, as well as the influencing effects of lifestyle and cultural factors on reproductive outcomes is needed.”
NURTURE’s findings are supported by a research conducted at the University of Kansas-Wichita, USA. The researchers there state that while the average birth rate after IVF using fresh eggs is 25.7%, this figure conceals the wide variation in the success rates for different ethnic groups.
After studying the records of more than 80,000 IVF treatment cycles carried out between 1999 and 2000, they found that the birth rate for black women was 18.7%, 20.7% for Asian women, 26.3% for white women and 26.7% for Hispanic women. They also learnt that black women had the highest miscarriage rate of 22%, compared to 13.9% for white women, 16.4% for Hispanic and 16.2% for Asian women.
Another US study, by researchers at the University of California, confirmed that Asian women had a lower pregnancy rate than non-Asians. The study looked at 1,200 IVF treatment cycles and found that the birth rate for Japanese, Indian and Chinese patients is about 60 per cent that of white women. However, the team stressed that the differences did not apply to natural conception.
Like the NURTURE team, the US teams are unsure of the reasons for these differences. According to Marion Damewoood, president of the American Society for Reproductive Medicine (ASRM), “The findings were preliminary but important, and we need to further explore these apparent racial differences to see if we can better understand and hopefully address their causes.”
While Asian couples may find these results worrying, it is crucial for all couples to be counselled on their realistic probabilities for IVF success. Based on these findings, Asian women are encouraged to seek treatment earlier to improve their chances of pregnancy.