First comes love, then comes marriage, and then post-birth stress arrives with the baby carriage. The joy of parenthood brings with it abrupt change and puts extreme strain on a marriage. In fact, for 90 percent of couples, marital bliss wanes and is replaced by a lack of satisfaction in the marital relationship within a year after the birth of their first child.

Researchers from the University of Denver and Texas A&M University conducted an eight-year study of 218 couples that found those with children experienced an accelerated decline of marital bliss, especially while adjusting to parenthood after the their first child is born. Although childless couples also experienced a decrease in marital bliss, the decline occurred much more gradually, over a long period of time. The study was published in the Journal of Personality and Social Psychology.

Of the 218 couples that participated in the study, those who encountered the strongest impact were the ones who were the most romantic before the arrival of a baby. According to Scott Stanley, a Denver University psychology professor, these couples got the "biggest jolt at baby time." In addition, those couples that had babies within a year of getting married as well as couples that had lower incomes underwent significant declines in marital satisfaction. Those couples who had been married longer or who had higher incomes fared much better in maintaining stability in their marriages.

Having children also comes with a heavy financial responsibility. Add today's economic instability, including the rising unemployment rates and plummeting retirement funds, and the strain on marriages becomes even greater. Economic and marital instability take a heavier toll on those with less education. According to recent data, almost half of those men having only a high school degree and having married by age 21 were divorced within 10 years of marriage. However, men who have a college education offer marriage a better chance for survival of both economic and emotional stressors that place a strain on the marital relationship. Only 10 percent of marriages in which the male was a college graduate over the age of 32 were found to have ended in divorce within a 10-year period.

However, this should not make one jump to the conclusion that remaining childless is the key to marital bliss and the secret to a happy marriage long-term. Stanley says, "Declines are somewhat normal in marriage. For those having children, they are going to be more concentrated around the time that you have children."

Stanley acknowledged that the findings of the study do not portray the comfort and long-lasting contentment that result from building a family together. He explained, "While there is a strain on the marriage from having children, a lot of couples gain this sort of deeper thing that you are growing as a family." In addition, tough times can lead people to re-evaluate life's priorities and take the time to have serious discussions that can build more intimacy and resilience.