Most research on migrant fertility focuses on immigrants from high-fertility countries who have moved to countries with lower fertility. But little is known about fertility trends among immigrant women from countries where fertility is lower than in the destination country.
Elevated fertility right after migration
We estimated the total fertility rates (TFRs) of migrants from low-fertility countries (Poland, Lithuania, and Germany) in Norway, a moderate-fertility country. We used Norwegian register data on immigrant women to calculate TFRs by duration of stay in Norway. We also explored differences between family migrants and women who migrate for other reasons, between women of different ages at arrival, and between those who emigrated again and those who remained in Norway. Our results showed that among immigrants from low-fertility countries, total fertility rates are elevated in the first years after migration. This is particularly true for women from Poland and Lithuania, who often arrive as family migrants and at peak fertility age (25 to 34 years).
Adaptation from below?
For non-family migrants, we found high or increasing TFR after arrival. This could be an example of “adaptation from below”, at least for those from Germany, whose fertility clearly increases in the first four to five years after migration. Since most of the women in this group are labor migrants, we may assume that labor market participation can accelerate adaptation to local fertility patterns (Andersson and Scott 2005, 2008).
Family migrants may explain previous inconclusive results
By using data on reason for migration, we may also shed light on why previous studies on immigrants from low-fertility areas have been inconclusive: in Western European destinations, a relatively large proportion of female migrants from low-fertility countries may have come for family reasons. This is hard to confirm with existing data, but it could be a reason for the high (but declining) fertility observed after immigration in European countries by Anderson (2004) and Lübke (2015) but not in non-European countries (Ford 1990; Hwang and Saenz 1997; Nahmias 2004; Okun and Kagya 2012).
Strong age effect warrants caution
Our results also show that for women who arrive at young ages, initial fertility upon arrival is higher than for non-immigrant women of the same age both in Norway and in the origin country, but fertility also increases for these women throughout their 20s. Thus, although fertility for young immigrant women is relatively high after arrival, this does not necessarily imply decreasing fertility by duration of stay. This age effect may partly explain the different fertility pattern for women from Germany in Norway, as they tend to arrive at younger ages. The age effect implies that immigrant women’s fertility changes by duration of stay, but should be interpreted with some caution; if the great majority of immigrant women arrive in their early 20s, the age effect suggests that we may see an increasing TFR by duration of stay even with a strong presence of elevated fertility right after arrival. On the other hand, if the great majority are 30 years or older at arrival, they will most likely have a decreasing TFR anyway simply because of this age effect.
Highest contribution to births right after migration
As fertility declines in many parts of Europe, including the Nordic countries, the results of this study indicate that immigrant women from low-fertility countries contribute most to the number of births right after their migration, or after a couple of years if they do not arrive as family migrants. Age and reason for migration contribute to these results. Fertility patterns of migrants can therefore provide helpful information to societies and governments in the context of decreasing births.