A Japanese researcher who likes to provoke controversy, Satoshi Kanazawa, has proclaimed that women with high IQs have few or no children. This leads him to proclaim in his book The Intelligence Paradox that "the urge to have kids among women drops by 25 percent with every extra 15 IQ points above a certain rate."
The correlation is likely true. The causation, though, is not likely to be that high IQ leads women to want fewer children, and certainly not that the highest IQ women want no children.
Rather, high IQ women have many choices in life, and are much more likely to have long years of education and highly demanding jobs than lower IQ women do. Therefore, the whole population of high IQ women is likely to have fewer children than women with average or low IQs. The correlation, though, is not the cause.