Nowadays, babies born under a healthy weight are often able to survive and grow to a healthy weight. However, when these babies grow into adults, they may have problems having babies of their own.
A recent study found that women born at a low birth weight or who were small for their gestational age (length of pregnancy) were at increased risk for having fertility problems as an adult.
The lead author of this study was Josefin Vikström, PhD, from the Division of Obstetrics and Gynecology at Linköping University in Sweden.
The study included 1,206 women in heterosexual relationships seeking infertility treatment at the Centre of Reproductive Medicine in the Linköping University Hospital between January 1, 2005 and December 31, 2010.
All of these women were born in Sweden in 1973 or later.
These women provided information on previous pregnancies, children, abortions and marriages.
The researchers then determined whether the reason for infertility was related to the female participant, her male partner, both the male and the female or unexplained with sperm samples, gynecological examinations and ultrasounds.
Information on the women's birth height, weight and week were obtained from the national Medical Birth Register.
The women who weighed 2,500 grams or fewer (about 5.5 pounds) when they were born were classified as low birth weight (LBW). Those born before 37 weeks of pregnancy were considered preterm. The women who were born under the average weight for their gestational age were considered to be small for gestational age (SGA), and those who were born over the average weight for their gestational age were considered to be large for gestational age (LGA).
The findings showed that 39 percent of the women had female-caused infertility issues, 27 percent had male-caused infertility issues, 7 percent had combined fertility issues and 28 percent of the participants had unexplained fertility issues.
The participants who had either female-caused or combined fertility issues were heavier as adults than the average weight of the group and more likely to be obese. A total of 91 percent of the participants had no previous children, and 12 percent had experienced previous miscarriages.
Of the women who had female-caused or combined fertility issues, 60 percent had one or more chronic illnesses. The researchers found that 3 percent of the participants had been born before 37 weeks of pregnancy, meaning that 4 percent of the participants with female-caused or combined fertility issues were born preterm.
Four percent of the participants were LBW, 3 percent were SGA, and three percent were born LGA.
The researchers determined that the women seeking treatment due to female causes were 2.4 times more likely to have been LBW compared to the women seeking treatment due to male or unexplained causes.
The participants with female-caused or combined infertility were 2.7 times more likely to be born SGA compared to the women with unexplained fertility issues.
Preterm birth or LGA did not affect the risk of each type of infertility.
Dr. Vikström and team mentioned some limitations of their study. First, the study population was small. Second, the participants who had unexplained infertility may have caused difficulties in interpreting the results because the cause of infertility may not have been discovered yet and may have been due to things other than infertility, such as sexual dysfunction.
Furthermore, some of the participants may not have told the truth about the length of time they had been trying to conceive. Lastly, the study population only included Swedish women, so the findings may not be applicable to the general population.
This study was published on March 10 in BMJ Open.
The Health Research Council of the Southeast of Sweden and the County Council of Östergötland provided funding.