As South Korea's fertility rate rebounds from historic lows, a clear divergence is emerging across age groups. While birth rates among women in their early 30s have recently stagnated, those in their late 30s and 40s continue to rise. Analysts attribute this shift to later marriages pushing the center of childbearing upward.
According to the National Data Agency on the 5th, the birth rate for women aged 35-39 rose year-over-year for 11 consecutive months through November 2024. After increasing 8.7 births per 1,000 women in January compared to the previous year, the upward trend continued through November, the most recent data available. The average birth rate for this age group reached 51.7 during the January-November period, up 5.1 from 46.6 in the same period a year earlier, crossing the 50-mark. Experts say late-30s births have entered a clear recovery phase.
Birth rates among women in their 40s showed similar momentum, rising or holding steady for 11 straight months without a single decline.
In contrast, birth rates for women aged 30-34 have recently lost steam. After maintaining relatively solid growth through the first half, the rate fell year-over-year in both October and November. The cumulative average birth rate of 73.3 for January-November remained above the prior year's 71.0, but the upward momentum slowed with three declines in the second half. Birth rates among women in their 20s have fluctuated. The rate for women aged 25-29 briefly rebounded in September and October before declining again in November, while women aged 24 and under showed slight decreases or flat trends overall.
"This appears to reflect a shift in the center of childbearing toward older ages within the 30s, driven by rising marriage ages," a National Data Agency official explained. As marriage itself is being delayed, first births are increasingly occurring after the mid-30s. The average age at first marriage for women rose from 30.0 in 2015 to 31.6 in 2024, an increase of 1.6 years over nine years. Analysts note that structural changes across age groups are occurring alongside the broader fertility rate rebound.