Clinical characteristics of vasa previa with low-lying placenta / 中华围产医学杂志

ABSTRACT

Objective:To investigate the clinical characteristics of vasa previa (VP) with low-lying placenta (LP).Methods:A retrospective case-control study was conducted on pregnant women with VP who delivered at Guangzhou Women and Children's Medical Center from January 2015 to August 2021. According to the status of LP, these cases were classified into VP with LP (VP+LP) and VP without LP (VP-LP) group. The cases diagnosed with placenta previa (PP, n=128) during the same period were collected as control. Maternal-fetal clinical characteristics and outcomes were compared among the three groups using t-test, Mann-Whitney U test, and Chi-square test (or Fisher's exact test). Results:During the study period, 116 VP cases were diagnosed, accounting for 0.085% (116/136 450) of all deliveries. Apart from one case of intrauterine death caused by non-VP reasons in the third trimester, there were 64 in the VP+LP group and 51 in the VP-LP group. VP+LP cases accounted for about 2.9% (64/2 219) of all the cases with PP or LP. The proportions of multiparae and women with a history of cesarean section were significantly higher in the VP+LP group than in the VP-LP group [62.5% (40/64) vs 39.2% (20/51), χ 2= 6.17, P=0.013; 31.3% (20/64) vs 13.7% (7/51), χ 2= 4.85, P=0.028]. Besides, a rare type of VP (type Ⅲ) was only found in the VP+LP group (9.4%, 6/64). The median gestational age at first diagnosis by prenatal ultrasound was significantly larger in the VP+LP group than in the VP-LP group [28.3 (23.6-31.7) vs 23.9 (23.3-25.9) weeks, Z=2.61, P=0.007]. There was no significant difference in the incidence of antepartum hemorrhage between the two groups. In contrast, the amount of postpartum hemorrhage was significantly increased in the VP+LP group [550 (436-732) vs 420 (300-540) ml, Z=3.37, P=0.001]. Compared with the VP-LP group, the VP+LP group showed a lower incidence of lower neonatal Apgar score (<7 at 5 min) and hypoxic-ischemic encephalopathy [0.0%(0/64) vs 6.9%(4/58), 0.0%(0/64) vs 8.6% (5/58), Fisher's exact test, both P<0.05]. No neonatal death was reported in the VP+LP and VP-LP groups. No significant difference in the incidence of antepartum hemorrhage was found between the VP+LP group and the PP group. Still, the median time at delivery was earlier [36.0 (34.3-36.9) vs 37.0 (35.7-37.3) weeks, Z=3.79, P<0.001], and the incidence of abnormal fetal heart rate was higher [10.9% (7/64) vs 3.1% (4/128), Fisher's exact test , P=0.044] in the VP+LP group. Furthermore, the neonatal NICU admission rate and the incidence of respiratory distress syndrome were significantly higher in the VP+LP group than in the PP group [36.4% (24/66) vs 12.1% (16/132), χ 2= 16.04, P<0.001; 25.8% (17/66) vs 12.1% (16/132), χ 2= 5.89, P=0.015]. Conclusions:For VP+LP cases, there might be an additional type (type Ⅲ VP). Patients with VP+LP would have more blood loss within 24 h after delivery and a higher risk of adverse neonatal outcomes. Intensive attention should be paid to those diagnosed with LP during the third trimester to identify any VP.