Preeclampsia, a disorder that significantly impacts maternal and fetal health during pregnancy, is characterized by high blood pressure and proteinuria. This study aimed to analyze maternal-fetal heart rate coupling in preeclamptic women during labor using time-frequency coherence (TFC) analysis. We compared two groups: the Preeclampsia Group (PG), with 11 participants, and the Control Group (CG), with 15 normotensive participants. Recordings were processed to extract 5-minute segments of maternal and fetal RR intervals, which were then analyzed using TFC methods. The results showed lower median TFC values in the PG (0.14 [0.12–0.22]) compared to the CG (0.15 [0.12–0.23]), indicating weaker maternal-fetal heart rate coupling in preeclamptic conditions. Statistical analysis confirmed significant differences between the groups (p = 0.0454). Our findings suggest reduced maternal-fetal coherence in preeclamptic conditions compared to normotensive controls. This diminished coherence likely reflects compromised physiological interactions between mother and fetus due to the pathological effects of preeclampsia, which may also alter fetal autonomic cardiac activity. We consider that TFC analysis could be a valuable tool for prenatal monitoring in preeclampsia, providing insights into fetal well-being and aiding in the management of pregnancies complicated by this condition.