How Similar are Cohabiting and Married Parents? Second Conception Risks by Union Type in the United States and Across Europe.

The increase in births within cohabitation in the United States and across Europe suggests that cohabitation and marriage have become more similar with respect to childbearing. However, little is known about additional childbearing after first birth. Using harmonized union and fertility histories from surveys in 15 countries, this study examines second conception risks leading to a live birth for women who have given birth within a union. Results show that women who continue to cohabit after birth have significantly lower second conception risks than married women in all countries except those in Eastern Europe, even when controlling for union duration, union dissolution, age at first birth, and education. Pooled models indicate that differences in the second conception risks by union type between Eastern and Western Europe are significant. Pooled models including an indicator for the diffusion of cohabitation show that when first births within cohabitation are rare, cohabiting women have significantly lower second conception risks than married women. As first births within cohabitation increase, differences in second conception risks for cohabiting and married women narrow. But as the percent increases further, the differentials increase again, suggesting that cohabitation and marriage are not becoming equivalent settings for additional childbearing. However, I also find that in all countries except Estonia, women who marry after first birth have second conception risks similar to couples married at first birth, indicating that the sequence of marriage and childbearing does not matter to fertility as much as the act of marrying itself.