Study finds both cousin marriage and older mothers double risk of birth defects

July 3, 2013, Lancet
Important research has shed light on the prevalence of congenital anomalies. Credit: US National Institutes of Health

Marriage between first cousins can more than double the risk of giving birth to a baby with a congenital anomaly (eg, heart and lung defects, Down syndrome), although the absolute risk is low, according to a multiethnic study of more than 11300 babies from the city of Bradford in the UK, published in The Lancet.

The high level of consanguineous marriage (marriage between blood relatives) within the large Pakistani community in the study* accounted for nearly a third (31%) of in babies of Pakistani origin.

A similar but expected increased risk in (over 34 years of age) was seen among white British women.

"It is important to note that the absolute increase in risk is small (from 3% to 6%), meaning that only a of babies born to couples who are blood relatives or older mothers (older White British mums have an increase in risk from 2% to 4%) will develop a congenital anomaly"**, cautions lead author Eamonn Sheridan from the University of Leeds in the UK.

The investigators looked at the influence of various maternal lifestyle and clinical risk factors (eg, smoking, obesity, and deprivation) in children with one or more anomalies from the Born in Bradford (BiB) study, which is tracking the health of 13 500 babies born at Bradford Royal Infirmary between 2007 and 2011, but found that the greatest risk factor was closely-related parents.

Overall rates of congenital anomalies in the BiB babies (305.74 per 10000 livebirths) were almost double national rates (165.90 per 10000 livebirths).

Socioeconomic status did not explain the increased rates of birth defects in offspring of blood relatives, despite two-thirds of the babies in the study coming from the most deprived fifth of the UK population.

What is more, in contrast with previous research, maternal smoking, , and obesity were not identified as for birth defects in this cohort, although the study may not have been large enough to detect the increases in risk associated with these factors.

A high level of maternal education was protective irrespective of ethnic origin, roughly halving the risk of having a baby with a congenital anomaly.

Consanguinity is a deeply rooted social trend with more than one billion people worldwide currently living in communities where consanguineous marriages are commonplace.

According to Neil Small from the University of Bradford who co-led the research, "This is the first study that has been able to explore all causes of in a population where there are sufficient numbers in both consanguineous and non-consanguineous groups to come to reliable conclusions. Clear and accessible information on these small but significant avoidable risks should be widely disseminated to local communities and be included as part of antenatal counselling and in the planning of healthcare services." **

Commenting on the study, Alan Bittles from Murdoch University and Edith Cowan University in Perth, Australia writes, "Sheridan and colleagues deserve major credit for their complex, time-consuming, and socially sensitive study… In view of the high community support for the Born in Bradford programme, a complementary substudy to determine the effects of consanguinity and community endogamy [when individuals marry within the same ethnic, class, or social group] on adult-onset diseases would be an invaluable investment for the future."

Explore further: The number of multiple births affected by congenital anomalies has doubled since the 1980s

More information: www.thelancet.com/journals/lan … (13)61132-0/abstract

Related Stories

The number of multiple births affected by congenital anomalies has doubled since the 1980s

February 5, 2013
The number of congenital anomalies, or birth defects arising from multiple births has almost doubled since the 1980s, suggests a new study published today (6 February) in BJOG: An International Journal of Obstetrics and Gynaecology.

Younger mothers and older mothers are at higher risk of adverse delivery outcomes

June 11, 2013
Younger mothers are at a higher risk of preterm birth while older mothers are more likely to have a caesarean section, suggests a new study published today (12 June) in BJOG: An International Journal of Obstetrics and Gynaecology.

Overweight mothers who smoke while pregnant can damage baby's heart

January 30, 2012
Mums-to-be who are both overweight and smoke during their pregnancy risk damaging their baby's developing heart, finds research published online in Heart.

Poor maternal and child health linked with premature high blood pressure, kidney disease

June 19, 2013
(Medical Xpress)—How babies grow and develop in the womb, as newborns and into childhood can put them at increased risk for premature high blood pressure, kidney disease and heart disease, according to a research review ...

Study reveals mothers' migrant status linked to newborns' weight

June 27, 2013
A new study involving Oxford University researchers suggests that the migrant status of couples in Hong Kong is a key factor in their babies' birth weights.

Rubella in pregnancy rare in US, but can be devastating for baby

March 28, 2013
(HealthDay)—Although rare in the United States, three babies with birth defects caused by rubella (or "German measles") were reported in 2012 and doctors need to be on the lookout for such cases, a new government report ...

Recommended for you

Rise in preterm births linked to clinical intervention

January 18, 2018
Research at the University of Adelaide shows preterm births in South Australia have increased by 40 percent over 28 years and early intervention by medical professionals has resulted in the majority of the increase.

New report calls into question effectiveness of pregnancy anti-nausea drug

January 17, 2018
Previously unpublished information from the clinical trial that the U.S. Food and Drug Administration relied on to approve the most commonly prescribed medicine for nausea in pregnancy indicates the drug is not effective, ...

New study finds 'baby brain' is real, but the cause remains mysterious

January 15, 2018
So-called "baby brain" refers to increased forgetfulness, inattention, and mental "fogginess" reported by four out of five pregnant women. These changes in brain function during pregnancy have long been recognised in midwifery ...

Sleep quality improves with help of incontinence drug

January 12, 2018
A drug used to curtail episodes of urinary incontinence in women also improves quality of sleep, a researcher at the Stanford University School of Medicine reports.

Frozen embryos result in just as many live births in IVF

January 10, 2018
Freezing and subsequent transfer of embryos gives infertile couples just as much of a chance of having a child as using fresh embryos for in vitro fertilization (IVF), research from Ho Chi Minh City, Vietnam, and Adelaide, ...

Study suggests air pollution breathed in the months before and after conception increases chance of birth defects

January 8, 2018
A team of researchers with the University of Cincinnati and Cincinnati Children's Hospital has found evidence that indicates that pre-and post-pregnant women living in an area with air pollution are at an increased risk of ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.