Trends in preterm birth in singleton deliveries in a Hong Kong population

A prospective, double-blinded cohort study using quantitative fetal fibronectin testing in symptomatic women for the prediction of spontaneous preterm delivery

BACKGROUND

Spontaneous preterm birth (PTB) affects 6.5% of deliveries in Hong Kong. Quantitative fetal fibronectin (fFN) is under-utilised as a test for PTB prediction in Hong Kong. Our objective was to evaluate the effectiveness of quantitative fFN in predicting spontaneous PTB in women with symptoms of threatened preterm labour (TPTL) in our population.

METHODS

A prospective, double-blinded cohort study of women with a singleton gestation and TPTL symptoms presenting to a tertiary hospital in Hong Kong between 24 + 0 to 33 + 6 weeks was performed from 1st October 2020 and 31st October 2021. Women with vaginal bleeding, ruptured membranes, and cervical dilation > 3 cm were excluded. The primary outcome was to test the characteristics of quantitative fFN in predicting spontaneous PTB < 37 weeks. Secondary outcome was to investigate the relationship between fFN value and time to PTB. Test characteristics of quantitative fFN at different thresholds were evaluated.

RESULTS

48 women with TPTL were recruited. All had fFN testing at admission with the results being concealed from the obstetrician managing the patient. 10 mothers had PTB (< 37 weeks' gestation). 7/48 (15%) had a subsequent PTB within 14 days from testing and 5 (10%) delivered within 48 h. The negative predictive value (NPV) of predicting delivery within 14 days was 97.3% and 100% when using a cut-off of < 50ng/ml and < 10ng/ml respectively. Using > 200 ng/ml as cut-off can also reliably predict delivery within 48 h - 7 days with positive predictive value PPV of 100%; as well as PTB before 37 weeks.

CONCLUSIONS

Quantitative fFN has predictive value for spontaneous PTB prediction in symptomatic women in a Hong Kong population. fFN concentration could help clinicians rule out PTB and avoid unnecessary interventions and hospitalisation.

Trend and causes of maternal death, stillbirth and neonatal death over seven decades in Hong Kong

BACKGROUND

Reducing maternal and perinatal mortality is a global objective. Hong Kong is a city with low maternal and perinatal mortality but little is known about the trend and causes of these deaths in this high-income city. We analyzed the maternal death, stillbirth and neonatal death since 1946 in Hong Kong.

METHODS

Data were extracted from vital statistics, based on the number of registered deaths and births, provided by the Department of Health, the Government of the HKSAR. The annual change rate of mortality was evaluated by regression analysis. Contextual factors were collected to assess the association with mortality.

FINDINGS

Between 1946 and 2017, the stillbirth rate (per 1,000 total births) reduced from 21·5 to 2·4; early and late neonatal deaths (per 1,000 live births) reduced from 14·1 and 18·1 to 0·7 and 0·4 in 2017, respectively. The maternal mortality ratio (per 100,000 live births) declined from 125 to 1·8.The causes of maternal and perinatal deaths were available since 1981 and 1980 respectively. The leading causes of death were thromboembolism (37·0%) and obstetric haemorrhage (30·4%) for maternal death; congenital problem (30·1%) and prematurity (29·0%) for neonatal death. No data on causes of stillbirth were available. No specific shift of pattern was observed in the causes of maternal and neonatal death with time. There were no cases of maternal death due to sepsis and only 2 cases (2·2%) of maternal deaths due to indirect cause.

INTERPRETATION

The maternal and perinatal death have reduced significantly in Hong Kong and maintained at the lowest level globally. Indirect maternal death and sepsis were unusual causes of maternal deaths. Use of ICD-PM stillbirth classification, setting up a maternal death confidential enquiry and adding pregnancy checkbox could be the next step to identify and categorize hidden burden.

FUNDING

Nil.

Relationship between viral load and pregnancy outcomes among hepatitis B carriers

OBJECTIVE

Pregnant hepatitis B carriers may have a higher risk of adverse pregnancy outcomes. Current evidences are conflicting regarding the relationship between hepatitis B virus (HBV) and various pregnancy complications, owing to the inclusion of women with different viral activity. This study is to evaluate the relationship between hepatitis B e antigen (HBeAg) status/HBV DNA level and pregnancy outcomes among pregnant hepatitis B carriers in Hong Kong.

MATERIALS AND METHODS

This was a retrospective analysis of a prospective multicenter observational study carried out in Hong Kong between 2014 and 2016. Pregnant HBV carriers were recruited. HBeAg was tested. HBV DNA level was quantified at 28-30 weeks of gestation. The rates of gestational diabetes mellitus (GDM), gestational hypertension, pre-eclampsia, preterm prelabour rupture of membranes (PPROM), preterm birth, low birth weight (LBW), macrosomia and mode of delivery were recorded.

RESULTS

679 pregnancies were analyzed. 23.3% of women were seropositive for HBeAg. The mean viral load (SD) at 28-30 weeks of gestation was 3.6 (2.5) log₁₀IU/ml. No statistically significant differences were found in the rates of GDM, gestational hypertension, pre-eclampsia, PPROM, preterm birth, LBW, macrosomia and mode of delivery among women with different viral load levels (≤2 log₁₀IU/ml, 2.01-6 log₁₀IU/ml and >6 log₁₀IU/ml). Positive maternal HBeAg status was not associated with pregnancy complications compared to seronegative women.

CONCLUSION

Seropositive HBeAg status or a higher level of HBV DNA during pregnancy did not pose a significant negative impact to the pregnancy outcomes.

The physical and developmental outcomes of children whose mothers are substance abusers: Analysis of associated factors and the impact of early intervention

BACKGROUND/OBJECTIVES

Maternal illicit drug use is associated with negative physical and developmental outcomes for their born children. We aim to find out the incidence of different developmental problems in a cohort of Chinese children born to drug-abusing mothers, compare the physical health and developmental outcomes of the subjects recruited in the Integrated Program to the Comprehensive Child Development Service (CCDS), and to study the potential factors on their associations.

METHODS

A retrospective longitudinal cohort study with frequent clinical assessments of the children's physical and developmental outcomes in a HKSAR's regional hospital from birth until 5 years old. 123 Children in Integrated Program were compared with 214 children in CCDS between 1 January 2008 and 28 February 2019. Cox regression analysis was performed to determine the possible factors associated with the developmental outcomes.

RESULTS

Developmental delay was detected in 129 children (38.9%). CCDS group has significantly higher incidence of cognitive delay (p = < 0.001), language delay (p = < 0.001), motor delay (p = < 0.001), social delay (p = 0.002), and global delay (p = 0.002). On Cox multivariable regression analysis, integrated program (HRadj 0.53, 95% C. I. 0.34-0.84), social support (HRadj 0.45, 95% C.I. 0.25-0.80), and maternal abstinence from drug use up to 2-year post-delivery (HRadj 0.62, 95% C.I. 0.40-0.95) were significant protective factors, while male gender (HRadj 1.73, 95% C.I. 1.18-2.54) was a significant risk factor.

CONCLUSION

CCDS achieves early engagement of drug-abusing expectant mothers during pregnancy, and an early integrated program with multidisciplinary collaboration was an independent factor in improving the developmental outcomes of these vulnerable children.

Clinical and biochemical markers of spontaneous preterm birth in singleton and multiple pregnancies

AIM

The aim of this study was to compare the clinical characteristics of singleton and twin pregnancies that resulted in spontaneous preterm births (sPTB) and to evaluate the prognostic value of phosphorylated insulin-like growth factor binding protein-1 (phIGFB-1) and placental alpha macroglobulin-1(PAMG-1) for sPTB prediction in symptomatic women.

PATIENTS AND METHODS

The study included 420 women and included two parts. Firstly, we performed a retrospective cohort study comparing pregnancy and neonatal outcomes in 170 women with singleton pregnancies and spontaneous preterm birth before 37 weeks of gestation with 150 women with twin pregnancies who delivered at the same gestational age. In order to obtain the link between clinical and biochemical predictors of preterm labor we organized the second part of the research. The second part was a prospective observational study in 100 women with singleton and twin pregnancies between 24 and 33 + 6 weeks of gestation and symptoms of threatening preterm labor and intact membranes. We assessed the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for phIGFBP-1 and PAMG-1 in terms of sPTB within 7 days and 14 days after testing.

RESULTS

The rate of preterm premature rupture of membranes was higher in singleton pregnancies (67.1 versus 42.8%, p = 0.034). Cervical shortening in multiples was diagnosed at an earlier mean gestational age than in singleton pregnancies (30.1 ± 4.3 versus 35.9 ± 3.1 weeks, p = 0.013). In the singleton pregnancies group, the rate of microbial cervical colonization and the rate of bacterial vaginosis were significantly higher than in twin pregnancies (49.4 versus 15.3%, p < 0.001; 32.9 versus 12.0%, p = 0.007, respectively). Premature twins had a longer oxygen dependency period, while the singletons were more predisposed to infectious morbidity. The study showed low sensitivity of phIGFBP-1 for sPTB, while the sensitivity of the PAMG-1 test was higher (sensitivity 60% and 90% within 7 days after testing and 50 versus 75% within 14 days after testing). Both tests showed a high NPV for sPTB (93.3% for phIGFBP-1 versus 98.9% for PAMG-1). The NPV for preterm labor in twins was also high for both tests (93% for phIGFBP-1 and 96% for PAMG-1).

CONCLUSION

Cervical shortening is the main risk factor of sPTB in women with twin pregnancies; sPTB among singletons is associated with ascendent infection, involving fetal membranes. The PAMG-1 test showed high PPV and NPV for sPTB in symptomatic women and could be a reliable prognostic tool in clinical obstetrics. High NPV was observed for phIGFBP-1 and PAMG-1 in twin pregnancies.

Trends in preterm birth in singleton and multiple gestations in the Netherlands 2008-2015: A population-based study

OBJECTIVE

Preterm birth is the most important cause of perinatal morbidity and mortality. Over the past years several preventive measures have been studied and implemented. Preterm birth percentage in 2015 in the Netherlands was 6.9 %, according to data from the European Peristat project, reporting on perinatal health in Europe. Various preventive measures might have influenced the incidence and outcome of preterm birth. Our aim was to give an overview of the trends in preterm births for both singleton and multiple gestations in the Netherlands in order to guide future research.

STUDY DESIGN

We studied a nationwide cohort including both singleton and multiple gestations without congenital anomalies between 2008 and 2015. Outcomes were total preterm birth (defined as birth before 37 weeks of gestation), spontaneous and iatrogenic preterm birth < 37 weeks, spontaneous and iatrogenic preterm birth percentages between 34-36 weeks, 32-34 weeks, 28-31 weeks and ≤ 27 weeks using a moving average technique. Trend analysis was performed using the Cochran Armitage test. Singleton and multiple gestations were analyzed separately.

RESULTS

Our final study population comprised 1,303.786 women with a singleton and 44,951 women with a multiple pregnancy. Preterm birth < 37 weeks in singletons decreased from 5.6 % in 2008 to 5.3 % in 2015 (P < 0.0001), in both spontaneous and iatrogenic preterm birth. Preterm birth ≤ 27 weeks increased from 0.40 % to 0.45 % (P for trend <0.0001). The number of multiple gestations decreased over the years, as well as the percentage of multiples conceived through IVF/ICSI. There was an increase in total and iatrogenic preterm birth < 37 weeks from 36.7-38.2% (P < 0.0001) in multiples. The number of multiples <32 decreased, in both the spontaneous and iatrogenic group.

CONCLUSION

In the Netherlands preterm birth risk in singletons decreased between 2008 and 2015 but an increase was noted in preterm birth ≤ 27 weeks. In multiples the total preterm birth risk increased, due to an increase in indicated preterm birth.

Early universal use of oral progesterone for prevention of preterm births in singleton pregnancy (SINPRO study): protocol of a multicenter, randomized, double-blind, placebo-controlled trial

Background

Preterm birth accounts for 75% of perinatal deaths and more than 50% of long-term neurological disabilities. For a singleton pregnancy, progesterone treatment is effective in prevention of preterm birth in women with an asymptomatic short cervix or a history of preterm birth. However, a large proportion of preterm births still is not currently preventable. The aim of this study is to determine whether early universal use of oral progesterone before 14 + 0 weeks of gestation can prevent preterm birth better than universal screening of cervical length at 18 + 0 to 23 + 6 weeks of gestation, followed by progesterone treatment in those with a short cervix in singleton pregnancy.

Methods

This is a multicenter, randomized, double-blind, placebo-controlled trial registered with ClinicalTrials.gov on 12 February 2018. Eligible consecutive pregnant women with singleton gestation attending antenatal outpatient clinics will be recruited after receiving counseling and signing the written consent form. Transvaginal cervical length measurement will be performed at recruitment (before 14 + 0 weeks of gestation) and between 18 + 0 and 23 + 6 weeks of gestation. After randomization, women will be randomly assigned to either the treatment group (oral dydrogesterone 10 mg three times daily) or the placebo group, and medication will be started before 14 + 0 weeks of gestation. Assigned groups will be unblinded if the cervical length is ≤ 25 mm between 18 + 0 and 23 + 6 weeks of gestation, and the management option for short cervix will be discussed (oral progesterone, vaginal progesterone, or cervical cerclage). The primary outcome is preterm birth before 37 + 0 weeks of gestation.

Discussion

Progesterone is used extensively in part of the in vitro fertilization program as luteal phase support, and it is not associated with teratogenicity. Universal progesterone supplementation may be a better approach to prevent preterm birth. This large, multicenter, randomized, double-blind, placebo-controlled trial will provide the best evidence, leading to the best strategy for the prevention of preterm birth.

Trial registration

ClinicalTrials.gov, NCT03428685. Registered on 12 February 2018.

Neonatal outcome in preterm deliveries before 34-week gestation - the influence of the mechanism of labor onset

Purpose: To evaluate neonatal outcomes in preterm infants with less than 34 weeks after spontaneous labor, preterm premature rupture of membranes (PPROM) or iatrogenic delivery and to clarify whether the mechanism of labor onset is a risk factor for adverse short-term neonatal outcome. Methods: We performed a retrospective case-control study, which included 266 preterm newborns with less than 34-week gestation, between 2011 and 2015. Neonatal outcomes were compared according to the mechanism of labor onset. Our primary outcomes were neonatal death, sequelae on hospital discharge and a composite of these two variables (combined neonatal outcome). Results: Compared to spontaneous preterm labor, iatrogenic preterm newborns were at increased risk of respiratory distress syndrome (RDS) [Odds Ratio (OR) 3.05 (95%CI 1.31; 7.12)], and need of exogenous surfactant administration [OR 3.87 (95%CI 1.60; 9.35)]. PPROM was associated with higher risk of neonatal sepsis [OR 12.96 (95%CI 1.18; 142.67)]. There were no differences regarding the combined outcome for iatrogenic [OR 0.94 (95%CI 0.33; 2.71)] or PPROM [OR 1.11 (95%CI 0.35; 3.49)] groups. Conclusions: In our study, the different mechanisms of labor onset are associated with different neonatal outcomes. Iatrogenic preterm birth was associated with an increased risk of RDS and a higher need of exogenous surfactant administration than spontaneous group. The rate of neonatal sepsis was significantly higher in PPROM group along with a higher prevalence of histological chorioamnionitis.

Trends in the incidence of retinopathy of prematurity over a 10-year period

AIM

To describe and evaluate the trends in the incidence of retinopathy of prematurity over a 10-year period in a tertiary hospital in Hong Kong.

METHODS

A retrospective review was performed on all preterm infants screened and/or treated for retinopathy of prematurity from January 2006 to December 2015 at Prince of Wales Hospital, Hong Kong. Preterm infants with incomplete records or transferred-in from other hospitals/region solely for treatment of ROP were excluded. The incidence of any ROP or Type 1 ROP was analysed with gestational age and birth weight over a 10-year period with consecutive 2-year intervals to evaluate the trends.

RESULTS

Of all 754 infants included in the study, 234 (31.0%) patients had any ROP and 34 (4.5%) infants developed Type 1 ROP. The incidence of any ROP demonstrated a statistically significant decreasing trend over the five consecutive 2-year intervals (p = 0.016), but the incidence trend of Type 1 ROP is not statistically significant. No infants weighing more than 1250 g developed Type 1 ROP.

CONCLUSION

We observed a decreasing trend in the incidence of any ROP across the 10-year period in a tertiary hospital in Hong Kong, while the incidence of Type 1 ROP remained stable at 4.5%. The factors leading to the trend were unclear. Improved prenatal care, changing proportion of cases with different birth weight and gestational age, oxygenation level practice in neonatal unit may all contribute to the decreasing trend. Revision of screening criteria may be made according to local experience to maximise cost-effectiveness.

Temporal trends of preterm birth in Shenzhen, China: a retrospective study

BACKGROUND

Preterm birth is the leading cause of child mortality under 5 years of age. Temporal trends in preterm birth rates are highly heterogeneous among countries and little information exists for China. To address this data gap, we investigated annual changes in preterm birth incidence rate and explored potential determinants of these changes in Shenzhen, China.

METHODS

A total of 1.4 million live births, during 2003-2012, were included from the Shenzhen birth registry. Negative-binominal regression models were used to estimate the annual percent changes in incidence. To identify the potential determinants behind temporal trends, we estimated the contribution of each changing risk factor to changes in rate by calculating the difference in population-attributable risk fraction.

RESULTS

Annual preterm birth incidence rates increased by 0.94% (95% CI 0.30%, 1.58%) overall, 3.60% (95% CI 2.73%, 4.48%) for medically induced, and 3.13% (95% CI 1.01%, 5.31%) for preterm premature rupture of membranes, but decreased by 2.34% (95% CI 1.62%, 3.06%) for spontaneous preterm labor. Higher maternal educational attainment (0.20 rate increase), lower proportion of inadequate prenatal care (0.15 rate reduction), more multipara (0.08 rate reduction), decreased proportion of preeclampsia or eclampsia (0.05 rate reduction), and larger proportion of young and older pregnant women (0.04 rate increase) were significant contributors to the overall change over time. Contributions of changing risk factors were different between preterm birth subtypes.

CONCLUSIONS

Preterm birth rate in Shenzhen, China increased overall during 2003-2012, although trends varied across three preterm birth subtypes. The rising rates were associated with changes in maternal education and age.

Avoiding late preterm deliveries to reduce neonatal complications: an 11-year cohort study

Background

Late preterm (LPT) newborns, defined as those born between 34 0/7 and 36 6/7 gestational weeks, have higher short- and long-term morbidity and mortality than term infants (≥37 weeks). A categorization to justify a non-spontaneous LPT delivery has been proposed to distinguish evidence-based from non-evidence-based criteria. This study aims to describe rates and temporal trends of non-spontaneous LPT neonates delivered according to evidence-based or non-evidence-based criteria and to evaluate the number of avoidable LPT deliveries, including severe neonatal morbidity rates and associated risk factors.

Methods

Retrospective cohort study including all LPT neonates born at a Swiss university maternity unit between January 1, 2002 and December 31, 2012. Trends of LPT neonates and neonatal complications were assessed across time using Poisson regression and risk factors for neonatal complications by logistic regression.

Results

Among 40,609 singleton live births, 4223 (10.5%) were preterm and 2017 (4.9%) LPT. In the latter group, 26.2% were non-spontaneous (evidence-based: 12.0%; non-evidence-based: 14.2%). The most frequent indications for evidence-based non-spontaneous LPT delivery were severe preeclampsia (51.8%) and abnormal fetal tracing (24.7%). Indications for non-evidence-based non-spontaneous LPT deliveries were hemorrhage (36.2%) and mild preeclampsia (15.7%). LPT birth rates remained stable over time. The rate of neonatal complications after non-evidence-based LPT birth remained high over time (43.8% vs. 43.5% in 2002 and 2012, respectively; P = 0.645), whereas the annual proportion of neonatal complications overall showed a decreasing trend (from 38.0% in 2002 to 33.5% in 2012; P = 0.051).

Conclusions

LPT birth rates were stable over time, but neonatal complications remained high, particularly after non-evidence-indicated LPT birth. A total of 287 LPT births could have been potentially avoided if an evidence-based protocol for delivery indications had been used. Efforts should be made to avoid non-spontaneous LPT births in order to reduce neonatal complications.

Trends in provider-initiated versus spontaneous preterm deliveries, 2004-2013

OBJECTIVE

The objectives of this study were as follows: (i) to estimate the proportion of preterm deliveries at a tertiary perinatal center that were provider-initiated versus spontaneous before and after a 2009 policy to reduce elective early-term deliveries, and (ii)to evaluate whether shifts in type of preterm delivery varied by race/ethnicity.

METHOD

We performed a retrospective cohort study of preterm deliveries over a 10-year period, 2004 to 2013, including detailed review of 929 of 5566 preterm deliveries, to designate each delivery as provider-initiated or spontaneous. We dichotomized the time period into early (2004 to 2009) and late (2010 to 2013). We used log-binomial regression to calculate adjusted risk ratios.

RESULT

Of the 46 981 deliveries, 5566 (11.8%) were preterm, with a significant reduction in the overall incidence of preterm delivery from 12.3 to 11.2% (P=0.0003). Among the 929 preterm deliveries analyzed, there was a reduction in the proportion of provider-initiated deliveries from 48.3 to 41.8% that was not statistically significant. The proportion of provider-initiated preterm deliveries among Black, but not White, women declined from 50.8 to 39.7% (adjusted relative risk: 0.66; 95% confidence interval (CI): 0.45 to 0.97). This coincided with a larger reduction in overall preterm deliveries among Black women (16.2 to 12.8%) vs White women (12.3 to 11.2%) (P interaction=0.038). By 2013, the incidence of preterm deliveries had decreased for both Black (12.1%) and White women (11.4%), and the difference was no longer statistically significant (P=0.7).

CONCLUSION

We found a reduction in preterm deliveries after a policy targeted at reducing elective early-term deliveries in 2009 that coincided with reductions in the proportion of provider-initiated preterm deliveries, especially among Black women.

Cohort study of the incidence of spontaneous preterm birth and septic abortion referred by pathological examination in Gifu prefecture in Japan

AIMS

To clarify the incidence of spontaneous preterm birth (PB) and septic abortion (sab) in Gifu prefecture in Japan.

STUDY DESIGN

This prospective, population-based cohort study was approved by our hospital's Institutional Review Board. All 36 hospitals (100%) in Gifu prefecture offering obstetrical services participated in the study. Patient enrollment criteria were: sab and PB from 22 to <37weeks gestation (WG), excluding for maternal and fetal indications. Pathological examinations before 36 WG and associated factors for both PB and chorioamnionitis (CAM) stage 3 were analyzed by multiple logistic regression analysis judging from minimum daily clinical information in Gifu prefecture.

RESULTS

The sab rate per all deliveries was 29/16871 (0.17%) at 16.9±2.9 WG. The total spontaneous PB rate was 615/16871 (3.65%) at 34.5±2.7 WG, with birth weight (BW) 2267±557g. There were 26 (0.15%) PBs from 22+0 to 27+6 WG (weeks+days) at 25.2±1.5 WG, with BW 745±199g. Among 214 pathological examinations, CAM was detected in 80% (sab) and 63% (PB<36 WG), respectively. Funisitis were 14% and 17% respectively. Episodes of serial genital bleeding and/or hematoma at <12 WG were more frequent in sab and earlier PB (<28 WG) associated with CAM stage 3 (odds 1.9, P<0.0001). Combined factors such as bleeding and past history of CAM correlated with earlier delivery at 23.4±5.9 WG (P=0.0032).

CONCLUSION

In Gifu prefecture, the incidence of sab was 0.17% (per all deliveries) and 3.65% of spontaneous PB. The combined risk of past CAM history and bleeding was associated with earlier delivery among total preterm birth.

Placental implantation abnormalities and risk of preterm delivery: a systematic review and metaanalysis

We sought to evaluate the extent of the association between placental implantation abnormalities (PIA) and preterm delivery in singleton gestations. We conducted a systematic review of English-language articles published from 1980 onward using PubMed, MEDLINE, EMBASE, CINAHL, LILACS, and Google Scholar, and by identifying studies cited in the references of published articles. Search terms were PIA defined as ≥ 1 of the following: placenta previa, placenta accreta, vasa previa, and velamentous cord insertion. Observational and experimental studies were included for review if data were available regarding any of the aforementioned PIA and regarding gestational age at delivery or preterm delivery. Case reports and case series were excluded. Studies were reviewed and data extracted. The primary outcome was gestational age at delivery or preterm delivery <37 weeks' gestation. Secondary outcomes included birthweight, 1- and 5-minute Apgar scores, neonatal intensive care unit (NICU) admission, neonatal and perinatal death, and small for gestational age. Of the 1421 studies identified, 79 met the defined criteria; 56 studies were descriptive and 23 were comparative. Based on the descriptive studies, the preterm delivery rates for low-lying/marginal placenta, placenta previa, placenta accreta, vasa previa, and velamentous cord insertion were 26.9%, 43.5%, 57.7%, 81.9%, and 37.5%, respectively. Based on the comparative studies using controls, there was decreased pregnancy duration for every PIA; more specifically, there was an increased risk for preterm delivery in patients with placenta previa (risk ratio [RR], 5.32; 95% confidence interval [CI], 4.39-6.45), vasa previa (RR, 3.36; 95% CI, 2.76-4.09), and velamentous cord insertion (RR, 1.95; 95% CI, 1.67-2.28). Risks of NICU admissions (RR, 4.09; 95% CI, 2.80-5.97), neonatal death (RR, 5.44; 95% CI, 3.03-9.78), and perinatal death (RR, 3.01; 95% CI, 1.41-6.43) were higher with placenta previa. Perinatal risks were also higher in patients with vasa previa (perinatal death rate RR, 4.52; 95% CI, 2.77-7.39) and velamentous cord insertion (NICU admissions [RR, 1.76; 95% CI, 1.68-1.84], small for gestational age [RR, 1.69; 95% CI, 1.56-1.82], and perinatal death [RR, 2.15; 95% CI, 1.84-2.52]). In singleton gestations, there is a strong association between PIA and preterm delivery resulting in significant perinatal morbidity and mortality.