NEW YORK (Reuters Health) - Parents of twins may be slightly more likely to get divorced than parents without twins, according to a new study.
The findings "are not surprising, given the stresses that caring for (twins) brings," Dr. John Moore, a pediatrician at Virginia Tech-Carilion School of Medicine in Roanoke who was not involved in the study, told Reuters Health.
The difference in divorce rates was small - only 1 percent - and the authors say they can't be sure what would account for the added risk. It's possible, they note, that either the emotional or financial stress of having twins was to blame.
Twins now make up between 3 and 4 percent of all births in the US. And as twins become more common with the increased use of fertility treatment, those small differences in divorce rates may add up, researchers say.
For the new study, Dr. Anupam Jena of Massachusetts General Hospital in Boston and his colleagues used data from the 1980 census to compare the marital status of parents who had twins as their first-born children versus those that did not - a total of more than 800,000 families.
They used the older data because it removed the chance that newer fertility treatments affected divorce rates, and later census surveys were not set up to determine whether families had twins.
In total, about 13 percent of mothers with a non-twin eldest child reported being divorced and not living with their child's birth father, compared to about 14 percent of mothers who had twins in their first birth.
Having twins made a bigger difference in parents' chance of divorcing when mothers had lots of kids and less income. Older twins and twin pairs that included at least one girl also drove up divorce rates more than young twins and boy-boy pairs, according to the findings published in Obstetrics & Gynecology.
Dr. Elizabeth Damato, who studies parents of twins at Case Western Reserve University in Cleveland but was not involved in the study, said that stress and lack of sleep may be even worse in parents of twins than in parents with one baby, and that those factors may contribute to higher divorce rates.
In Damato's studies, "parents felt stressed because they spent so much time attending to their (infants') care needs ... that they don't have time to really enjoy them," she told Reuters Health.
Financial factors also likely play a role, Jena said, especially as children get older and there are two sets of clothes to buy and two sets of activities and educations to fund at the same time. With twins, clothes and cribs can't be purchased once and passed from one to the other, as with non-twin siblings.
Mothers in the study who had twins as their first children also had an average of more children overall than mothers who didn't have twins - 2.7 children versus 2.0 children - resulting in more financial pressure for those families, and probably more daily stress as well.
Estimates have shown that depending on a family's total income, the average cost of raising a child from birth to age 18 may be as high as $250,000.
The authors don't suggest avoiding having twins, if such a thing were even possible. The findings are a way to be aware of the challenges that may come in the future, Jena said.
"To warn families ahead of time that something like this may occur later on in life would not be a bad idea," Jena told Reuters Health. For pediatricians who see twins, he said, it would be helpful "to have a little more insight, and pay a little bit more attention to some of the family dynamics that can occur."
"Having (twins) is going to be challenging, even for the most well-adjusted people," Moore said. "Don't make yourself feel guilty about feeling stressed and feeling tired. Give yourself a break."
SOURCE: bit.ly/haHP4A Obstetrics & Gynecology, April 2011.