Are pregnant women happier?
This paper uses data from the Behavioral Risk Factor Surveillance System (BRFSS) to study the relationship between pregnancy and life satisfaction for women of childbearing age. The results show strong differences by race. Pregnancy has the strongest positive correlation with happiness for Whites, a smaller but still statistically significant positive correlation for Hispanics, and no relationship for Blacks. The results cannot be explained by differences in other demographics such age, income, education, or marital status. Within each racial group, the results hold across different categories for all these characteristics. There is evidence that racial differences in the effects of pregnancy on emotional and social support from others can partly explain this result.
Source: “Are Pregnant Women Happier? Racial Differences in the Relationsip Between Pregnancy and Life Satisfaction” from Department of Economics, Hamilton College
You can read an excellent article on happiness here.
For a more thorough list of techniques to make yourself happy you may want to check out this book.