Elsevier

Early Human Development

Volume 101, October 2016, Pages 85-89
Early Human Development

Placental histopathology lesions and pregnancy outcome in pregnancies complicated with symptomatic vs. non-symptomatic placenta previa,☆☆

https://doi.org/10.1016/j.earlhumdev.2016.08.012Get rights and content

Highlights

  • We compared pregnancy outcome and placental pathology in symptomatic (bleeding) vs. non-symptomatic placenta previa (PP)

  • We studied the effect of the coexisting retro-placental hemorrhage (RPH) in cases of symptomatic PP on pregnancy outcome

  • The symptomatic previa group was characterized by older women, more smokers, thrombophilia, and preterm deliveries

  • Placentas in the symptomatic group had higher rates of weight < 10th%, RPH, and villous changes of maternal malperfusion

  • Coexisting RPH in symptomatic PP was associated with adverse neonatal outcome independent of background factors.

Abstract

Background

The mechanisms involved in bleeding in cases of placenta previa (PP) and the effect on pregnancy outcome is unclear.

Objectives

We aimed to compare pregnancy outcome and placental histopathology in pregnancies complicated with symptomatic (bleeding) vs. non-symptomatic PP, and to study the effects of the co-existence of histopathological retro-placental hemorrhage (RPH) in cases of symptomatic PP on neonatal and maternal outcomes.

Study design

Labor and maternal characteristics, neonatal outcome and placental histopathology lesions of pregnancies with PP, delivered between 24 and 42 weeks, during 2009–2015, were reviewed. Results were compared between PP who had elective cesarean delivery (CD) (previa group) and PP with bleeding necessitating emergent CD (symptomatic previa group). Placental lesions were classified to lesions consistent with maternal malperfusion or fetal thrombo-occlusive disease (vascular and villous changes), and inflammatory lesions.

Results

Compared to the previa group (n = 63), the symptomatic previa group (n = 74) was characterized by older patients (p < 0.001), higher rate of smokers (p = 0.005), thrombophilia (p = 0.038), and preterm deliveries (p < 0.001). Placentas within the symptomatic previa group were smaller, with higher rates of weight < 10th% (p = 0.02), RPH (p < 0.001) and villous changes related to maternal malperfusion (p = 0.023). As compared to symptomatic PP without RPH, co-existence of RPH was associated with higher rate of adverse neonatal outcome (p < 0.001) and maternal blood transfusion (p = 0.02). On multivariate regression analysis, composite adverse neonatal outcome was found to be dependent on coexisting RPH (OR = 2.8, 95%CI 1.2–11.7, p = 0.03), and low gestational age (OR = 3.1, 95%CI 1.6–4.9, p = 0.02).

Conclusions

Symptomatic placenta previa is associated with increased placental malperfusion lesions suggesting an association of maternal malperfusion with abnormal placental separation. The coexisting finding of RPH with symptomatic placenta previa can be seen as a marker for more extensive/severe placental separation, hence the association with maternal transfusion requirements and poorer fetal outcome.

Introduction

Placenta previa is defined as placental implantation that takes place in the lower uterine segment, partially or completely covering the internal cervical os [1]. The incidence of placenta previa is about 1 in 200 term pregnancies [2], and the rate appears to be rising as a consequence of the increasing rate of cesarean deliveries (CD) [3]. Advanced maternal age (over 35 years), multiparty, smoking and infertility treatment appears to be additional risk factors for placenta previa [3], [4], [5], [6]. Diagnosis is usually done during the second half of pregnancy by vaginal or trans-abdominal ultrasound [7]. Symptomatic (bleeding) placenta previa is associated with increased maternal and neonatal morbidity and mortality [1], [5], [8], [9], [10]. There is a threefold increase in neonatal mortality rate, in comparison with normally positioned placenta [11].

Studies on placental histopathology evaluation in cases of placenta previa are scarce, although abnormal placental implantation may be associated with different placental developmental abnormalities, that may provide specific explanations for adverse neonatal outcome [12]. Histopathology evaluation of placental bed biopsies revealed that placenta previa is associated with normal physiological changes in the spiral arterioles [13]. Stereological analysis has been shown that the volume of blood vessels of the placental villi is significantly increased as compared to controls [14]. Moreover, the mechanism that involve in bleeding is unclear. It is usually, but not always, related to uterine contractions, cervical effacement and dilation leading to separation of the placenta from the underlying decidua [14].

We aimed to compare pregnancy outcome and placental histopathology lesions in pregnancies with placenta previa, with and without bleeding events requiring emergent CD. We hypothesized that in cases of symptomatic placenta previa, due to abnormal placentation, higher rates of placental pathological lesions will be observed, as compared to non-symptomatic placenta previa. Additionally, we aimed to study the consequences of the existence of retro-placental hemorrhage in symptomatic placenta previa on neonatal and maternal outcomes.

Section snippets

Materials and methods

The medical records of all women diagnosed with placenta previa (complete or partial), who underwent CD, and their placentas were sent to histology evaluation, at 24 to 42 gestational weeks, between January 2009 to December 2015, were reviewed. The study was conducted in a single university hospital, with an annual volume of approximately 5000 deliveries and a total cesarean delivery rate of approximately 22.5%. In all cases diagnosis of placenta previa was confirmed by trans-vaginal ultrasound

Results

During the study period 32,246 deliveries occurs in our institute. Of them, 137 CD (0.42%) for placenta previa were performed and met the inclusion criteria for the study (after excluding 11 cases of multiple pregnancy and 10 cases of concomitant placenta accreta). The mean gestational age at the initial diagnosis of placenta previa was 27.1 ± 3.1 gestational weeks.

Out of those CDs 74 (54%) underwent non-elective CDs due to vaginal bleeding (symptomatic previa group) and 63 (46%) underwent

Comment

The present study demonstrates that pregnancies complicated with symptomatic placenta previa differ in maternal and pregnancy characteristics and placental histopathology lesions, as compared to pregnancies complicated with non- symptomatic placenta previa, without bleeding episodes.

The etiology of placenta previa is multifactorial and it is associated with adverse maternal and neonatal outcomes [1], [5], [8], [9], [10]. Possible etiopathogenesis of placenta previa is injured endometrium and

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    This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

    ☆☆

    All authors have no conflicts of interest to report.

    1

    First two authors, EW and HM, contributed equally to the article.

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