Step 1: Read the definition carefully.
We need live births counted against women of reproductive age, per 1000, in one year. That specific denominator, women aged 15 to 49, is the clue.
Step 2: Write the ratio.
\[ GFR = \frac{\text{live births in the year}}{\text{women aged 15-49}} \times 1000 \]
This is exactly the General Fertility Rate.
Step 3: Rule out the sound alike terms.
Total Fertility Rate sums up age-specific rates to estimate children per woman over a lifetime, not an annual per-1000 figure. Gross Reproduction Rate only counts female babies. Net Reproduction Rate goes further and folds in the mother's survival chances. None of these match the plain "live births per 1000 women" wording.
Step 4: Conclude.
\[ \boxed{\text{General Fertility Rate}} \]