Most studies on internal migration and fertility conclude that migration leads to lower fertility. This phenomenon is opened explained in the context of the social mobility and assimilation models. But there are other studies that report conflicting results. This note proposes an alternative model that may reconcile the conflicts. A "migration cycle" posits a non-linear migration-fertility relationship whereby fertility falls on account of economic and psychic hardships caused by displacement following migration, and then rises during the period of adjustment, as child bearing becomes easier. It may only be in the long run, with further improvements in income and education and fuller assimilation into the new environment, when a sustained fertility declined can be expected. The model is borne out by Philippine data form the 1973 NDS. It would seem then that, after a temporarily alleviating the fertility problem, migration tends to aggravate it. What this implies for policy is to quicken the period of adjustment for migrants so that sustained fertility decline can occur sooner than otherwise. The implication for research is to test the model with longitudinal data and with data on other countries as well.
