Perinatal and neonatal outcome and late pulmonary sequelae in infants born after preterm premature rupture of membranes

Active Versus Expectant Management for Preterm Premature Rupture of Membranes at 34-36 Weeks of Gestation and the Associated Adverse Perinatal Outcomes

OBJECTIVE

 To compare the type of management (active versus expectant) for preterm premature rupture of membranes (PPROM) between 34 and 36 + 6 weeks of gestation and the associated adverse perinatal outcomes in 2 tertiary hospitals in the southeast of Brazil.

METHODS

 In the present retrospective cohort study, data were obtained by reviewing the medical records of patients admitted to two tertiary centers with different protocols for PPROM management. The participants were divided into two groups based on PPROM management: group I (active) and group II (expectant). For statistical analysis, the Student t-test, the chi-squared test, and binary logistic regression were used.

RESULTS

 Of the 118 participants included, 78 underwent active (group I) and 40 expectant management (group II). Compared with group II, group I had significantly lower mean amniotic fluid index (5.5 versus 11.3 cm, p = 0.002), polymerase chain reaction at admission (1.5 versus 5.2 mg/dl, p = 0.002), time of prophylactic antibiotics (5.4 versus 18.4 hours, p < 0.001), latency time (20.9 versus 33.6 hours, p = 0.001), and gestational age at delivery (36.5 versus 37.2 weeks, p = 0.025). There were no significant associations between the groups and the presence of adverse perinatal outcomes. Gestational age at diagnosis was the only significant predictor of adverse composite outcome (x² [1] = 3.1, p = 0.0001, R² Nagelkerke = 0.138).

CONCLUSION

 There was no association between active versus expectant management in pregnant women with PPROM between 34 and 36 + 6 weeks of gestation and adverse perinatal outcomes.

The effects of antenatal corticosteroids therapy on very preterm infants after chorioamnionitis

PURPOSE

To evaluate the effectiveness of antenatal corticosteroids (AC) therapy on outcomes of very low birthweight infants with histologic chorioamnionitis.

METHODS

We performed a retrospective analysis of 10,935 single infants born at a gestational age between 22 + 0 and 33 + 6 weeks and birth weight <1,500 g. Clinical data were obtained from the Neonatal Research Network that included the tertiary neonatal intensive care units throughout Japan between 2003 and 2008.

RESULTS

Data of 7,896 infants were available for the period 2003-2008 and were included in the analysis. According to logistic regression analysis, AC were significantly associated with reduced mortality [odds ratio (OR) = 0.50; p < 0.001], lower incidence of respiratory distress syndrome (OR = 0.72; p < 0.001), neonatal seizure (OR = 0.65; p = 0.003) and intraventricular hemorrhage (OR = 0.68; p = 0.001) in cases after histologic chorioamnionitis compared with the cases had no AC therapy (n = 3,271 vs. 4,625). Antenatal corticosteroids were significantly associated with reduced mortality [odds ratio (OR) = 0.60; p < 0.001] among the cases without histologic chorioamnionitis.

CONCLUSION

In the retrospective population-based study in Japan, AC exposure was significantly associated with a lower rate of death and neurological morbidity in cases with histologic chorioamnionitis. These outcome data in Japan will be important for further improvement of antenatal practice and care.

Subtypes of preterm birth and the risk of postneonatal death

OBJECTIVE

To examine the differences in postneonatal death risk among 3 clinical subtypes of preterm birth: preterm premature rupture of membranes (PROM), indicated preterm birth, and spontaneous preterm labor.

STUDY DESIGN

We analyzed the 2001-2005 US linked birth/infant death (birth cohort) datasets. The preterm birth subtypes were classified using information on the birth certificate: reported PROM, induction of labor, cesarean section, and complications of pregnancy and labor. Cox proportional hazard models were used to estimate covariate-adjusted hazard ratios and 95% CIs for postneonatal death (from days 28 to 365). Estimation was given for preterm birth subtypes in a week-by-week analysis. Causes of death were analyzed by preterm birth subtype and then separately at 24-27, 28-31, and 32-36 weeks of gestation.

RESULTS

For the total of 1895350 singleton preterm births who survived the neonatal period, the postneonatal mortality rate was 1.11% for preterm PROM, 0.78% for indicated preterm birth, and 0.53% for spontaneous preterm labor. Preterm PROM was associated with significantly higher risk of postneonatal death compared with spontaneous preterm labor in infants born at 27 weeks gestation or later. Similarly, indicated preterm birth was associated with a significantly higher risk of postneonatal death than spontaneous preterm labor in infants born at 25 weeks gestation or later. Preterm PROM and indicated preterm birth were associated with greater risk of death in the postneonatal period compared with spontaneous preterm labor, irrespective of the cause of death.

CONCLUSION

Subtypes of preterm birth carry different risks of postneonatal mortality. Prevention of preterm-related postneonatal death may require more research into the root causes of preterm birth subtypes.

Misinterpreting odds ratio in the articles published in korean journal of family medicine

BACKGROUND

In reporting results of case-control studies, odds ratios are useful methods of reporting findings. However, odds ratios are often misinterpreted in the literature and by general readers.

METHODS

We searched all original articles which were published in the Korean Journal of Family Medicine from 1980 to May 2011 and identified those that report "odds ratios." Misinterpretation of odds ratios as relative risks has been identified. Estimated risk ratios were calculated when possible and compared with odds ratios.

RESULTS

One hundred and twenty-eight articles using odds ratios were identified. Among those, 122 articles were analyzed for the frequency of misinterpretation of odds ratios as relative risks. Twenty-two reports out of these 122 articles misinterpreted odds ratios as relative risks. The percentage of misinterpreting reports decreased over years. Seventy-seven reports were analyzed to compare the estimated risk ratios with odds ratios. In most of these articles, odds ratios were greater than estimated risk ratios, 60% of which had larger than 20% standardized differences.

CONCLUSION

In reports published in the Korean Journal of Family Medicine, odds ratios are frequently used. They were misinterpreted in part of the reports, although decreasing trends over years were observed.

A systematic review of intentional delivery in women with preterm prelabor rupture of membranes

OBJECTIVE

To evaluate the effect of intentional delivery versus expectant management in women with preterm prelabor rupture of membranes (PPROM).

METHODS

We searched electronic databases and trials registries, contacted experts, and checked reference lists of relevant studies. Studies were included if they were randomized controlled trials comparing intentional delivery versus expectant management after PPROM, the gestational age of participants was between 30 and 36 weeks, and the study reported one of several pre-determined outcomes.

RESULTS

Four studies were included in the meta-analysis. No difference was found between intentional delivery and expectant management in neonatal intensive care unit (NICU) length of stay (LOS) (weighted mean difference (WMD) -0.81 day, 95% confidence interval (CI) -1.66, 0.04), respiratory distress syndrome (risk difference (RD) -0.01, 95% CI -0.07, 0.06), and confirmed neonatal sepsis (RD -0.01, 95% CI -0.05, 0.04). One study found a significantly lower incidence of suspected neonatal sepsis among the intentional delivery group (RD -0.31, 95% CI -0.50, -0.12; number needed to treat (NNT) 3, 95% CI 2, 8). Maternal LOS was significantly shorter for the intentional delivery group (WMD -1.39 day, 95% CI -2.03, -0.75). There was a significant difference in the incidence of clinical chorioamnionitis favoring intentional delivery (RD -0.16, 95% CI -0.23, -0.10; NNT 6, 95% CI 5, 11). There was no significant difference in the incidence of other maternal outcomes, including cesarean section (RD 0.05, 95% CI -0.01, 0.11).

CONCLUSIONS

Intentional delivery may be favorable to expectant management for some maternal outcomes (chorioamnionitis and LOS). There is insufficient evidence to suggest that either strategy is beneficial or harmful for the baby. Large multicenter trials with primary neonatal outcomes are required to assess whether intentional delivery is associated with less neonatal morbidity.

[Premature rupture of membranes before 32 weeks of gestation: prenatal prognosis factors]

OBJECTIVE

Premature preterm rupture of membranes (PPROM) accounts for a significant part of overall perinatal mortality and morbidity. This study aims to define potential prognostic factors for neonatal outcome.

PATIENTS AND METHODS

One hundred and thirty-one pregnancies complicated with PPROM at between 26 and 32 weeks were retrospectively reviewed over a three-year period. The influence of chorioamnionitis on perinatal morbidity and mortality was assessed using a composite outcome.

RESULTS

On admission, gestational age (GA) at diagnosis, fetal heart rate anomalies and increasing severity of clinical features of chorioamnionitis were significantly related with an adverse outcome. Significant factors associated with a favourable outcome were an administration of steroids for lung maturation, prophylactic antibiotics and tocolytic therapies. Stratifying according to GA at PPROM, the survival rates were 43 and 52% at before 22 weeks and between 22 and 26 weeks respectively. The prognosis dramatically improved after 26 weeks with an 84.6% rate of survival without impairment. Although this rate reached 97.5% after 30 weeks, there was no statistical evidence supporting any benefit to prolong pregnancies beyond this point. The complete expression of chorioamnionitis independently increased the mortality rate by 41% (OR=1.41; 95% CI [0.99-2.01]. Overall, the most relevant factor was GA at delivery, levelling the prognostic value of GA at diagnosis.

DISCUSSION AND CONCLUSION

If no consensus rules PPROM at the moment, the most efficient prognosis factor before 34 weeks is mostly determined by GA at delivery.

Acute and chronic respiratory diseases in pregnancy: associations with spontaneous premature rupture of membranes

OBJECTIVE

To examine whether acute and chronic respiratory diseases are associated with an increased risk of spontaneous premature rupture of the membranes (PROM).

METHODS

We used the 1993-2004 National Hospital Discharge Survey data of singleton deliveries in the USA (N = 41 250 539). The International Classification of Diseases Ninth Revision was utilized to identify acute (acute upper respiratory diseases, viral/bacterial pneumonia, and acute bronchitis/bronchiolitis) and chronic (chronic bronchitis and asthma) respiratory conditions and spontaneous PROM. All analyses were adjusted for potential confounders.

RESULTS

The incidence of PROM was 5%, and rates of acute and chronic respiratory conditions were 2.1 and 9.5 per 1000 pregnancies, respectively. Chronic bronchitis was associated with a reduced risk of PROM (RR 0.39, 95% CI 0.31, 0.48). Asthma was significantly associated with PROM at preterm (RR 1.15, 95% CI 1.14, 1.17) and term (RR 1.27, 95% CI 1.23, 1.30). Stratification by race showed that acute upper respiratory disease was associated with preterm PROM in whites (RR 1.90, 95% CI 1.71, 2.11) and blacks (RR 6.76, 95% CI 5.67, 8.07). Viral/bacterial pneumonia was associated with preterm PROM in blacks and term PROM in both races. Asthma was associated with term PROM in blacks but not whites.

CONCLUSIONS

Acute respiratory diseases and asthma during pregnancy are associated with spontaneous PROM, with substantially stronger association among blacks than whites. We speculate that timely diagnosis and treatment, coupled with closely mentoring of pregnant women may help reduce the rate of PROM and associated complications.

Risk factors for previable premature rupture of membranes or advanced cervical dilation: a case control study

OBJECTIVE

The purpose of this study was to identify risk factors for second trimester premature preterm rupture of membranes or advanced cervical dilation in a high-risk population.

STUDY DESIGN

A retrospective case control study was performed that compared women with premature preterm rupture of membranes or advanced cervical dilation to term control subjects. The cases included all singleton pregnancies between 14 and 24 weeks of gestation with premature preterm rupture of membranes or advanced cervical dilation between 1996 and 2000. The next 2 term deliveries were chosen as control subjects. The variables compared between cases and control subjects included pregnancy history, infectious and medical histories, cervical/uterine procedures, and habits. This study had institutional review board approval.

RESULTS

There were 102 women with premature preterm rupture of membranes, 56 women with advanced cervical dilation, and 316 control subjects. The mean gestational ages for premature preterm rupture of membranes or advanced cervical dilation were 20 +/- 2.6 and 19.9 +/- 2.6 weeks. Tobacco use, history of or current cervical incompetence, previous second trimester delivery, previous termination at <20 weeks of gestation, and previous premature preterm rupture of membranes were associated significantly with premature preterm rupture of membranes or advanced cervical dilation compared with term control subjects. When controlled for parity, age, marital status, and race, these variables remained significant. Bacterial vaginosis in current pregnancy was associated significantly with only advanced cervical dilation but not premature preterm rupture of membranes compared with control subjects. A history of Chlamydia was most common in the term control subjects (19.6%).

CONCLUSION

In a high-risk population of inner city women, only pregnancy history and tobacco use distinguished women with second trimester premature preterm rupture of membranes or advanced cervical dilation from term control subjects. No infectious risk factors distinguished control women from women with premature preterm rupture of membranes. The only modifiable risk identified was tobacco use.

Epidemiology of preterm birth and neonatal outcome

In industrialized countries, 5-11% of infants are born preterm (<37 weeks' gestation), and the rate has been increasing since the early 1980s. Preterm births account for 70% of neonatal deaths and up to 75% of neonatal morbidity, and contribute to long-term neurocognitive deficits, pulmonary dysfunction and ophthalmologic disorders. In the past several decades, major progress has been made in improving the survival of extremely premature newborns, mostly attributable to timely access to effective interventions that ameliorate prematurity-associated mortality and morbidity such as antenatal administration of corticosteroids and exogenous surfactant therapy, rather than preventing preterm births. However, the societal and healthcare costs to care for survivors with severe morbidity and neurological handicaps remain substantial. Future research should concentrate on the ways to reduce long-term health sequelae and developmental handicaps among survivors of infants born preterm, as well as elucidating the mechanisms and aetiology of preterm births.

Neonatal complications of preterm premature rupture of membranes. Pathophysiology and management

Midtrimester PROM is an infrequent, yet potentially disastrous complication of pregnancy. The most likely neonatal complication is preterm delivery with associated morbidity and mortality risks. Unique neonatal complications following PPROM include skeletal deformations and pulmonary hypoplasia related to prolonged oligohydramnios exposure. A systematic approach to an infant with respiratory insufficiency following PPROM delivery is possible with an understanding of the pathophysiology of pulmonary hypoplasia. Neonatal management should include immediate resuscitation including surfactant replacement, with careful attention to techniques of mechanical ventilation to avoid early volutrauma. Adjunctive therapies directed at pulmonary hypertension may now permit survival of some infants with less severe forms of pulmonary hypoplasia.

Preterm delivery for maternal or fetal indications: maternal morbidity, neonatal outcome and late sequelae in infants

OBJECTIVE

To assess maternal morbidity, and neonatal outcome and especially long term sequelae in infants born preterm due to maternal or fetal indications.

DESIGN

Analysis of retrospective cohort.

SETTING

Oulu University Central Hospital, Finland.

POPULATION

One hundred and three women, who were between the 24th and the 33rd week of pregnancy, delivered by caesarean delivery because of maternal or fetal indications. They were matched with 103 women who had spontaneous preterm delivery at corresponding gestational weeks between 1990-1997.

MAIN OUTCOME MEASURES

Maternal morbidity, reasons for caesarean delivery, neonatal mortality and morbidity rates, and later development of the infants.

RESULTS

Pre-eclampsia was diagnosed in 57% of the women in the indicated group and only in one woman in the control group. All infants in the indicated group and almost a third in the control group were born by caesarean birth; the main indication was threatening fetal asphyxia. There was a significant difference in neonatal mortality rates between the groups (175 vs 78 per thousand live births in the indicated vs control infants; RR 2.3, 95% CI 1.02, 4.9) and the main cause of death was respiratory insufficiency: 64% in the indicated group and 22% in the controls; RR 2.9, 95% CI 0.8, 10. Respiratory distress syndrome occurred more often (73% vs 53%, RR 1.4, 95% CI 1.1, 1.7) and it was more severe and more complicated in infants in the indicated group, compared with those in the control group. Symptomatic chronic lung disease at one year of age was more common in infants in the indicated group than in the control group (15% vs 3%; RR 4.6, 95% CI 1.4, 15.9).

CONCLUSIONS

Not only the risks of neonatal mortality and morbidity but also long term pulmonary consequences, appear to be greater in infants born preterm by indicated delivery than in preterm infants born spontaneously at corresponding weeks.

Recent advances in the pathophysiology and management of preterm premature rupture of the fetal membranes

During the past few years, meaningful progress has been achieved in our understanding of the pathophysiology of preterm premature rupture of membranes. In addition, more evidence has been presented in favor of induction and delivery for rupture between 34 and 37 weeks and expectant management for rupture before 34 weeks. New approaches are being suggested to complement expectant management. The purpose of this article is to review this recent information about the pathophysiology and management of women with preterm premature rupture of membranes.