Prognosis of preterm premature rupture of membranes between 20 and 24 weeks of gestation: A retrospective cohort study

Background

The previous study on prognosis of preterm premature rupture of fetal membranes (pPROM) near the limit of viability showed various survival rate raging from 26 to 57 %%. This may be partly due to the fact that treatment of prematurely born babies vary from one country to another, or sometimes within a single country. In Japan, resuscitation efforts are made to newborns of early gestational age, normally from 22 weeks of gestation.

Objective

To assess the natural history and short- and long-term prognosis in pregnancies complicated by preterm premature rupture of membranes (pPROM) near the limit of viability in a hospital in Japan.

Method

We conducted a single-center retrospective cohort study. Cases with diagnosis of pPROM at a gestational age of 20–23 6/7 weeks and delivered in our hospital between April 2007 and December 2017 were examined.

Result

66 cases were included and of those, 54 (81.1 %) newborns survived to discharge. Of the neonates who survived to discharge, 42 (77.8 % of survivors) experienced severe morbidity at the time of discharge. Multivariate logistic regression analysis showed that later gestational age at pPROM and longer latency period were significantly associated with survival with no severe morbidities (per one day increase, adjusted odds ratio (OR) 1.37, 95 % CI 1.03–1.83, p = 0.033 and per one day increase, adjusted OR 1.11, 95 % CI 1.02–1.21, p = 0.015). Of 23 cases followed at 36 months, 8 (34.8 %) showed developmental delay.

Conclusion

The survival rate was significantly higher than the previous studies, yet many of the survivors experienced short-term severe morbidity. Of those who experienced short-term severe morbidity, however, more than half showed normal range development at 36 months.

Real prevalence of neural tube defects in Japan: How many of such pregnancies have been terminated?

The vital role of folic acid is to reduce the risk of having a neonate afflicted with neural tube defects. The prevalence of neural tube defects (myelomeningocele and anencephaly) has been reported in an incomplete form over the last 40 years in Japan. We aimed to evaluate the total number of neural tube defects including those delivered or terminated, to clarify the proportion of those terminated, and to internationally compare their prevalence. Through information on >311 000 deliveries obtained from 262 hospitals/clinics for 2 years of 2014 and 2015, we identified that the rate of total neural tube defects (termination of pregnancy, live births and stillbirths) was 8.29 per 10 000 deliveries for the year 2014 and was 8.72 for 2015, which were 1.5 and 1.6 times higher than the respective values (live births and stillbirths) reported. It is also observed that the ratio of the total number of myelomeningocele (termination of pregnancy, live births, and stillbirths) to that of anencephaly was approximately 1:1.2, that a half of pregnancies afflicted with neural tube defects were terminated, and that the proportion of termination of pregnancy due to myelomeningocele and due to anencephaly was 20% and 80%, respectively. Internationally, the real prevalence of neural tube defects in Japan was comparatively high, ranking fifth among the seven developed countries. In conclusion, the real prevalence of total neural tube defects was approximately 1.5 times higher than that currently reported by the Japan Association of Obstetricians and Gynecologists.

The anti-phospholipid antibody-dependent and independent effects of periodontopathic bacteria on threatened preterm labor and preterm birth

PURPOSE

Periodontal disease is considered to be a risk factor for threatened preterm labor (TPL) and preterm birth (PB), but pathogenic mechanisms have not yet been elucidated. We hypothesized that infection with periodontopathic bacteria may enhance thrombosis through molecular mimicry with TLRVYK peptides on beta-2 glycoprotein I, a target molecule in anti-phospholipid syndrome. This study aimed to examine the effects of periodontitis on TPL and PB.

METHODS

Ninety-five pregnant women (47 TPL and 48 healthy subjects) participated. Periodontal clinical parameters and periodontopathic bacteria were examined. Molecular mimicry between TLRVYK peptides and homologous peptides on the periodontopathic bacteria was examined by enzyme-linked immunosorbent assay (ELISA) using rabbit polyclonal antibodies specific for the respective peptides (SIRVYK on Aggregatibacter actinomycetemcomitans, TLRIYT on Porphyromonus gingivalis, and TLALYK on Treponema denticola). Serum high-sensitivity C-reactive protein, anti-TLRVYK and anti-SIRVYK IgG antibodies were measured using ELISA.

RESULTS

Among the rabbit antibodies specific for the bacterial homologous peptides, only anti-SIRVYK IgG antibody reacted with TLRVYK peptides. Multivariable analysis showed that anti-SIRVYK IgG antibody was significantly associated with diagnosis of TPL. Of 95 births, 14 (14.7 %) delivered preterm. The preterm birth rate was higher in the anti-SIRVYK IgG antibody >median group than in the ≤median group. Of the 47 TPL subjects 13 had PB, and ordinal logistic regression analysis revealed that past smoking, presence of P. gingivalis and anti-SIRVYK IgG antibody were significantly correlated with PB.

CONCLUSIONS

Infection with P. gingivalis and the antibody response to SIRVYK might be associated with TPL and PB.

Roles of endogenous nitric oxide synthase inhibitors and endothelin-1 for regulating myometrial contractions during gestation in the rat

This study investigated the roles of endogenous nitric oxide synthase (NOS) inhibitors and endothelin-1 (ET-1) for regulating myometrial contractions during gestation in the rat. Basal and stimulated cyclic GMP production with L-arginine as a NOS substrate or sodium nitroprusside (SNP) as a NO donor were significantly enhanced at the middle of gestation (14th day), while these were greatly decreased at term (22nd day), suggesting the accelerated NO production and/or up-regulation of guanylate cyclase at the middle of gestation. NOS within the myometrium was mainly Ca(2+)dependent and partly Ca(2 + )independent and remained unaffected by aminoguanidine as an inhibitor of inducible NOS in non-pregnant and gestational myometrium. NOS activity per se and endothelial NOS (eNOS) protein expression remained unchanged at the middle and term gestation. Neuronal NOS (nNOS) and inducible NOS (iNOS) proteins were undetectable. SNP at a high concentration of 100 micromol/l failed to modify the spontaneous and ET-1-induced rhythmic contractions in non-pregnant and gestational myometrium. Contents of N(G)-monomethyl-L-arginine (L-NMMA) plus asymmetric N(G),N(G)-dimethyl-L-arginine (ADMA) as endogenous NOS inhibitors and ET-1 within the myometrium were significantly decreased at 14th and 20th days of gestation, whereas these were significantly increased at term gestation (22nd day) and after delivery. There was a significant and positive correlation between endogenous NOS inhibitor content and ET-1. ET-1 within the myometrium was significantly increased with a concomitant decrease in cyclic GMP production after the intraperitoneal application of authentic L-NMMA for 2 weeks, suggesting that the impaired NO production with endogenous NOS inhibitors would result in increased ET-1 content. These results suggest that endogenous NOS inhibitors such as L-NMMA and ADMA play an important role for regulating NO production in rat myometrium. The impaired NO production due to accumulated endogenous NOS inhibitors possibly results in increased ET-1 content within the myometrium, thereby increasing myometrial contractions at term gestation and after delivery.