Step 1: Recall the short list of pregnancy-safe antihypertensives, then find the choice that falls outside it.
Step 2: Methyldopa, labetalol and hydralazine form the core of pre-eclampsia management and are considered safe for the fetus.
Step 3: Atenolol is the outlier; long-term use links to intrauterine growth restriction, so it is deliberately avoided in pre-eclampsia. That identifies it as the drug not used.
\[\boxed{\text{Atenolol}}\]