First-Trimester Clinical Characteristics and Pregnancy Outcomes in Women with Recurrent Pregnancy Loss

<b>Objective</b>: To describe first-trimester maternal, biochemical, biophysical, and ultrasound characteristics in women with recurrent pregnancy loss (RPL) compared to women without RPL. <b>Methods</b>: This was a retrospective cohort study analyzing data from 4440 pregnant women, including 142 women with previous RPL. Maternal and pregnancy characteristics, first-trimester biochemical markers, biophysical assessments, early-onset preeclampsia (EOPE) risk, and perinatal outcomes were compared. <b>Results</b>: Women with RPL were older (37.8 vs. 34.0 years, <i>p</i> < 0.001) and had higher rates of antiphospholipid syndrome (4.9% vs. 0.9%, <i>p</i> < 0.001), other thrombophilias (5.6% vs. 0.8%, <i>p</i> < 0.001), and thyroid disorders (14% vs. 7.5%, <i>p</i> = 0.010) than women without RPL. First-trimester uterine artery pulsatility index (UtA-PI) values, pregnancy-associated plasma protein-A (PAPP-A) levels, mean arterial pressure, and final risk for EOPE were comparable between groups. However, the RPL group had higher rates of very high risk for PE (10.6 vs. 5.1, <i>p</i> = 0.011). Likewise, second-trimester UtA-PI was higher in this group (1.10 vs. 1.01, <i>p</i> = 0.045). Aspirin and low molecular weight heparin prophylaxis were more frequent in women with RPL (23.8% vs. 9.6%, <i>p</i> < 0.001; 14.7% vs. 0.1%, <i>p</i> < 0.001). Regarding perinatal outcomes, we found a higher incidence of second-trimester intrauterine demise in the RPL group (6.4% vs. 1.4%, <i>p</i> = 0.011), with no other differences observed in the remaining outcomes. <b>Conclusions:</b> Women with RPL exhibit distinct maternal characteristics and worse pregnancy outcomes, although first-trimester markers do not seem to significantly differ from findings in women without RPL. These findings underscore the importance of tailored screening and intervention protocols to improve perinatal outcomes in this high-risk population.