Girls born unexpectedly small or underweight are twice as likely to experience infertility and other fertility issues as adults compared to girls born at a normal weight, suggest the findings of a new study published in the journal BMJ Open.
According to the National Institutes of Health, a low birth weight is less than 5.5 pounds while high birth weight is more than 8.8 pounds. The normal birth weight for babies is between 5.5 and 8.8 pounds. Both low birth weight and high birth weight can cause significant health problems for the baby.
With advances in medicines, more babies born with low birth weights are surviving into adulthood, meaning that more problems associated with low birth weight will continue to surface.
For the present study, the researchers assessed data on all women born in Sweden since 1973 who sought infertility treatment at the Centre of Reproductive Medicine between 2005 and 2010. A total of 1,293 women in heterosexual relationships participated in the study. The researchers analyzed cause of infertility from medical records and obtained details on birth size, age, and weight from the national medical birth register in Sweden.
Within the couples, the cause of infertility was attributed to the woman in 38.5 percent of cases, to men in 27 percent of cases, to combined causes in seven percent of cases, and to unexplained reasons in 28 percent of cases.
Of the total women, four percent had been born prematurely, approximately four percent were underweight at birth, and just under six percent were “unexpectedly small babies.”
According to the study, the women with fertility problems attributed to the female were nearly 2.5 times more likely to have been born underweight compared with the women whose fertility problems were attributed to the male or in which the cause was unknown. These women were also nearly three times more likely to have been born unexpectedly small.
Women with fertility problems were also more likely to be overweight, a known risk factor for infertility. The majority of the women in the study were a healthy weight; however, around 25 percent were overweight, five percent were obese, and 2.5 percent were underweight.
Birth weight, therefore, appears to be a factor in fertility during adulthood.
Conclude the researchers:
“As medical research and care advances, more infants will be born [with low birth weight or small size] and survive, which in turn might influence future need of infertility treatment. Thus, infants born with birth characteristics that deviate from the norm may be at greater risk of difficulties in childbearing later on in life. Since this study is the first of its kind, more studies are needed to verify the associations.”
Another recent study found that the use of endocrine-disrupting chemicals, or EDCs, during the controversial oil and natural gas drilling technique called hydraulic fracturing, or fracking, can also cause infertility.
References
Birth Weight: http://www.nlm.nih.gov/medlineplus/birthweight.html
Girls born underweight ‘more likely to be infertile adults’: http://www.medicalnewstoday.com/articles/273812.php
Image Credits
Baby Feet: http://www.freeimages.com/photo/1040792
