Maternal and Neonatal Outcomes Resulting from Antepartum Hemorrhage in Women with Placenta Previa and Its Associated Risk Factors: A Single-Center Retrospective Study

Prevalence of placenta previa among deliveries: An update systematic review and meta-analysis after the introduction of the two-child policy in Mainland China

Background

As birth policy can affect maternal and infant health, we sought to identify whether and how the introduction of the two-child policy might have affected the prevalence of placenta previa in pregnant women in mainland China.

Methods

In this update meta-analysis and systematic review, we searched PubMed, Web of Science, the Cochrane Library, Weipu, Wanfang, and the China National Knowledge Infrastructure (CNKI) databases for studies evaluating the prevalence of placenta previa in China published between the inception of each database and March 2024, with no restrictions. Two investigators independently extracted the data from each included study. We then combined the prevalence of placenta previa using random-effects models.

Results

We included 128 studies in our analysis, 48 more than in our previous review. The prevalence of placenta previa among Chinese pregnant women was 1.44% (95% confidence interval (CI) = 1.32, 1.56). After the implementation of the two-child policy, the prevalence increased significantly, from 1.25% (95% CI = 1.16, 1.34) to 4.12% (95% CI = 3.33, 4.91).

Conclusions

The prevalence of placenta previa increased significantly from the one-child policy period to the two-child policy period among mainland Chinese pregnant women, with varying trends across regions. This change requires the attention of health officials and timely adjustment of resource allocation policies.

Registration

PROSPERO: CRD42021262309.

Risk Factors and Pregnancy Outcomes of Antepartum Hemorrhage in Women with Placenta Previa

Placenta previa (PP) is one such complication related to several adverse pregnancy outcomes. Adverse outcomes are likely greater if PP coexists with antepartum hemorrhage (APH). This study aims to evaluate the risk factors and pregnancy outcomes of APH in women with PP. This retrospective case-control study included 125 singleton pregnancies with PP who delivered between 2017 and 2019. Women with PP were divided into two groups: PP without APH (n = 59) and PP with APH (n = 66). We investigated the risk factors associated with APH and compared the differences between both groups in placental histopathology lesions due to APH and the resulting maternal and neonatal outcomes. Women with APH had more frequent antepartum uterine contractions (33.3% vs. 10.2%, P = .002) and short cervical length (< 2.5 cm) at admission (53.0% vs. 27.1%, P = .003). The placentas from the APH group had lower weight (442.9 ± 110.1 vs. 488.3 ± 117.7 g, P = .03) in the gross findings, and a higher rate of villous agglutination lesions (42.4% vs. 22.0%, P = .01) in the histopathologic findings. Women with APH in PP had higher rates of composite adverse pregnancy outcomes (83.3% vs. 49.2%, P = .0001). Neonates born to women with APH in PP had worse neonatal outcomes (59.1% vs. 23.9%, P = .0001). Preterm uterine contractions and short cervical length were the most significant risk factors for APH in PP.

Blood Type and Outcomes in Pregnant Women with Placenta Previa

Background

Placenta previa increases the risks of obstetrical complications. Many studies have reported a link between various ABO blood types and pregnancy complications. This study is aimed at describing and comparing the characteristics and outcomes of women with placenta previa by ABO blood type.

Methods

Data for this study was obtained from a retrospective cohort study between January 1, 2014, and June 30, 2019, of all clinically confirmed placenta previa in a university-based tertiary medical center. Both types of A, B, O, AB, and combining O and non-O blood types were compared to the characteristics and outcomes.

Results

1678 participants with placenta previa were included in this study. The highest participants were blood type O with 666 (39.7%), followed by type A with 508 (30.3%) and type B with 395 (23.5%), and the lowest participants were AB with 109 (6.5%). Blood type AB had a higher incidence of antepartum hemorrhage (p = 0.017), predelivery anemia (p = 0.036), and preterm birth (p = 0.015) in placenta previa women. Meanwhile, the incidence of rhesus D positive (97.9% vs. 95.8%, p = 0.012) and twins (5.0% vs. 2.7%, p = 0.011) was higher in the non-O group, and the incidence of neonatal asphyxia (5.9% vs. 9.2%, p = 0.016) was lower in the non-O group.

Conclusion

Type AB blood may be a potential risk factor for women with placenta previa. This finding may help provide any obstetrician to predict the risk of complication for placenta previa women by the ABO blood types.

Factors Associated with Placenta Previa: A Retrospective, Single-Center Study in Turkey

BACKGROUND The incidence of placenta previa is gradually increasing. The major risk factor is a history of cesarean section (CS). Such patients may experience severe bleeding during pregnancy and surgery. Patients with placenta previa were classified based on risk factors in this study. This retrospective study from a single center in Turkey aimed to evaluate the factors associated with placenta previa in 151 women. MATERIAL AND METHODS Patients with placenta previa were grouped by the presence/absence of prior CS. Group 1 (123 patients) had undergone at least 1 CS, and Group 2 (28 patients) had not undergone CS. The diagnosis of placenta previa was made by ultrasound. Placenta previa was defined as cases where the placenta crossed the internal os. Duration of surgery, bleeding during surgery, and the amounts of erythrocyte suspensions required were compared between groups. RESULTS Of Group 1 patients, 67.5% had anterior placenta previa compared to 46.4% in Group 2. The mean duration of surgery was: 52.0±19.2 and 28.5±4.6 min (P<0.001); the number of sutures was 8.4±2.4 and 5.9±0.9 (P<0.001); the bleeding volumes were 720.3±536.2 and 344±137.0 mL (P<0.001); and the amount of erythrocyte suspension administered intraoperatively was 0.2±0.7 and 0.0±0.0 unit (P=0.032). CONCLUSIONS Mean duration of surgery, number of sutures, bleeding volume, and intraoperatively applied ES volumes were significantly different between groups. Identification of placenta previa patients who have undergone prior CS is vitally important in terms of preoperative preparation.

Risk of preterm birth for placenta previa or low-lying placenta and possible preventive interventions: A systematic review and meta-analysis

OBJECTIVE

To investigate the risk of preterm birth in women with a placenta previa or a low-lying placenta for different cut-offs of gestational age and to evaluate preventive interventions.

SEARCH AND METHODS

MEDLINE, EMBASE, CENTRAL, Web of Science, WHO-ICTRP and clinicaltrials.gov were searched until December 2021. Randomized controlled trials, cohort studies and case-control studies assessing preterm birth in women with placenta previa or low-lying placenta with a placental edge within 2 cm of the internal os in the second or third trimester were eligible for inclusion. Pooled proportions and odds ratios for the risk of preterm birth before 37, 34, 32 and 28 weeks of gestation were calculated. Additionally, the results of the evaluation of preventive interventions for preterm birth in these women are described.

RESULTS

In total, 34 studies were included, 24 reporting on preterm birth and 9 on preventive interventions. The pooled proportions were 46% (95% CI [39 - 53%]), 17% (95% CI [11 - 25%]), 10% (95% CI [7 - 13%]) and 2% (95% CI [1 - 3%]), regarding preterm birth <37, <34, <32 and <28 weeks in women with placenta previa. For low-lying placentas the risk of preterm birth was 30% (95% CI [19 - 43%]) and 1% (95% CI [0 - 6%]) before 37 and 34 weeks, respectively. Women with a placenta previa were more likely to have a preterm birth compared to women with a low-lying placenta or women without a placenta previa for all gestational ages. The studies about preventive interventions all showed potential prolongation of pregnancy with the use of intramuscular progesterone, intramuscular progesterone + cerclage or pessary.

CONCLUSIONS

Both women with a placenta previa and a low-lying placenta have an increased risk of preterm birth. This increased risk is consistent across all severities of preterm birth between 28-37 weeks of gestation. Women with placenta previa have a higher risk of preterm birth than women with a low-lying placenta have. Cervical cerclage, pessary and intramuscular progesterone all might have benefit for both women with placenta previa and low-lying placenta, but data in this population are lacking and inconsistent, so that solid conclusions about their effectiveness cannot be drawn.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO https://www.crd.york.ac.uk/prospero/, identifier CRD42019123675.

The main features of placental abruption: Clinical presentation and treatment

Placental abruption is defined as the premature separation of the placenta from the uterus. Rapid diagnosis and adequate medical intervention provide a good outcome, which is not possible in all countries. Any bleeding that occurs in the second half of pregnancy raises the suspicion of placental abruption, which is associated with fetal and maternal morbidity and mortality. The clinical picture and consequences for the fetus depend on the degree of bleeding and the amount of blood. Complete abruption leads to the disruption of fetal circulation and oxygenation, asphyxia, and stillbirth. In case of partial abruption, the consequences for the fetus depend on the degree of bleeding. In complete abruption, fetal death is inevitable unless an emergency cesarean delivery is undertaken.