Except there is the awkward fact that it is the third world which has higher population growth rates and the nordics have are leaders in low birth rates.
Consider that the world is complex and there's more than one factor. Conservatives cultures have higher birth rates, as do families with lower educational levels. Both are common in the third world. In developed countries, there's constant conversation about how people are being priced out of feeling safe or able to hit traditional milestones like having children. I myself didnt have kids in a marriage only because we couldn't afford it, and I worked around the clock hoping to soon.
Africa has by far the highest rates, and the Nordics are far below replacement, but some of the lowest (and noticeably lower than the Nordics) are South Korea (0.7), Taiwan (0.9), and Singapore (0.9). Replacement would require ~2.1.
https://ourworldindata.org/grapher/children-born-per-woman?t...