Page URL: https://www.bionews.org.uk/page_92819

Fertility treatment success linked to weight and race, study claims

14 February 2011
Appeared in BioNews 595

New research suggests that women from ethnic minority backgrounds may have lower success rates with fertility treatment.

Research has already shown that there are important racial and ethnic differences, with particular minority groups experiencing a greater risk of 'adverse reproductive outcomes', including low birth weight and higher infant mortality. However, these disparities are just emerging and less well established among women undergoing fertility treatments, namely IVF. It has been suggested that higher rates of obesity among women from minority backgrounds may be a contributory factor in these differences.

To address this question, scientists collected information on nearly 32,000 fertility procedures performed at US clinics in 2007. They found that obese women were less likely to have a baby compared to normal weight women. However, even when weight was accounted for, black, Hispanic and Asian women still had lower success rates compared to white women. Following IVF treatment, 45% of white women became pregnant, compared to 43% of Hispanic women, 38% of Asian women and 36% of black women.

Further differences were also observed in maintaining the pregnancy and giving birth: 85% of white women who carried their babies for at least 22 weeks eventually gave birth, compared to 80% of Asian and Hispanic women and 76% of black women.

These results more firmly establish a racial disparity in reproductive success among women receiving fertility treatment and refute the notion that weight differences are responsible. This leaves the question of what other factors could account for these discrepancies.

The team led by Dr Barbara Luke of Michigan State University suggests a few possibilities. One potential explanation could be body fat distribution. Increased body fat is thought to affect reproductive success by altering hormone levels and increasing inflammatory factors. Although overall body fat did not explain the differing success rates, the distribution of fat may do. Black women tend to carry more of their excess weight in the upper body, which is thought to bear greater health risks than fat around the hips and thighs.

Black women are also more likely to have uterine fibroids, which are associated with lower pregnancy and birth rates. The scientists also speculate a role for vitamin D deficiency, which has been linked to an increased risk of a vaginal infection called bacterial vaginosis, increasing the chances of complications during pregnancy.

Individuals are able to synthesise vitamin D endogenously when their skin is exposured to sunlight. However, increased pigmentation in darker skinned people can hinder this process and can lead to deficiency in countries where sunlight is less abundant.

Other factors such as age and type of infertility did not explain the racial differences either. However, the research team was restricted by the limited amount of available information on the women.

The researchers called for further studies to be carried out, where 'future research', they suggested, 'should focus on clarifying the underlying causes of these disparities'.

The findings were published in the journal Fertility and Sterility.

SOURCES & REFERENCES
Racial and ethnic disparities in assisted reproductive technology pregnancy and live birth rates within body mass index categories
Fertility and Sterility |  27 January 2011
Weight, race tied to fertility treatment success
Reuters |  9 February 2011
RELATED ARTICLES FROM THE BIONEWS ARCHIVE
11 November 2013 - by Dr Linda Wijlaars 
The outcome of fertility treatment may be influenced by the ethnicity of the mother, a UK study has found...
17 September 2012 - by Sarah Pritchard 
The eggs of women undergoing IVF are significantly more likely to contain chromosomal abnormalities if the woman is severely obese than eggs belonging to women who are of a healthy weight, a recent US study suggests...
13 June 2011 - by Dr Kimberley Bryon-Dodd 
US researchers have found a link between an ovarian hormone called anti-mullerian hormone (AMH) and IVF success. The findings suggest AMH testing could help clinicians tailor doses of ovary-stimulating drugs to improve women's egg production and likelihood of pregnancy...
11 April 2011 - by Dr Jess Buxton 
This evening debate, organised by the Progress Educational Trust (PET) in partnership with University College London's Genetics Institute, and supported by the Wellcome Trust, marked the launch of PET's project 'Genes, Ancestry and Racial Identity: Does it Matter Where Your Genes Come From?' The first of what promises to be a very lively series of debates...
17 January 2011 - by Dr Marianne Kennedy 
Scientists have found that the health of infants born through IVF depends on which techniques were used and their infertility diagnoses....
10 January 2011 - by Dr Gabrielle Samuel 
Researchers have developed a calculator that they claim can be used to provide people who are having fertility problems with an assessment of the likelihood of having a successful outcome following IVF...
15 November 2010 - by Kyrillos Georgiadis 
UK-based researchers have developed a new screening technique which could double or triple IVF success rates. The new test allows for any chromosomal abnormalities to be detected in embryos before they are implanted into the mother....
1 November 2010 - by Rosemary Paxman 
An embyro screening test could significantly increase IVF success rates, US researchers have found...
20 September 2010 - by Gozde Zorlu 
Higher fertilisation rates have been found in women undergoing IVF in spring, according to new research presented at the World Congress of Fertility and Sterility last week...
HAVE YOUR SAY
Log in to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions


Syndicate this story - click here to enquire about using this story.