Complications of prolonged PROM and oligohydramnios

Severe midtrimester oligohydramnios: treatment strategies

PURPOSE OF REVIEW

Nearly 1% of pregnancies are affected by some type of midtrimester oligohydramnios. Evidence is currently accumulating that suggests the better efficacy of the new therapeutic procedures relative to conventional management. This review summarizes the available evidence.

RECENT FINDINGS

The prolongation of the period between the diagnosis of oligohydramnios and delivery following amnioinfusion and amniopatch techniques appears to be strongly associated with the gestational age and whether the situation was based on rupture of the membranes or not. Case series reveal that amnioinfusion significantly improves the perinatal outcome and prolongs the pregnancy in severe second-trimester oligohydramnios in both idiopathic cases and those involving rupture of the amniotic membranes [preterm prelabor rupture of the membranes (PPROM)]. There is clear evidence of a lower frequency of perinatal complications and successfully prolonged gestation in iatrogenic PPROM after the amniopatch technique relative to population controls.

SUMMARY

Identification of potentially modifiable risk factors for the successful prolongation of pregnancy complicated with midtrimester oligohydramnios, and previable PPROM is needed for the improvement of treatment strategies and prognosis. Randomized trials are needed to determine whether amniotic fluid-replenishing strategies can improve pregnancy outcomes.

Extrinsic factors influencing fetal deformations and intrauterine growth restriction

The causes of intrauterine growth restriction (IUGR) are multifactorial with both intrinsic and extrinsic influences. While many studies focus on the intrinsic pathological causes, the possible long-term consequences resulting from extrinsic intrauterine physiological constraints merit additional consideration and further investigation. Infants with IUGR can exhibit early symmetric or late asymmetric growth abnormality patterns depending on the fetal stage of development, of which the latter is most common occurring in 70-80% of growth-restricted infants. Deformation is the consequence of extrinsic biomechanical factors interfering with normal growth, functioning, or positioning of the fetus in utero, typically arising during late gestation. Biomechanical forces play a critical role in the normal morphogenesis of most tissues. The magnitude and direction of force impact the form of the developing fetus, with a specific tissue response depending on its pliability and stage of development. Major uterine constraining factors include primigravida, small maternal size, uterine malformation, uterine fibromata, early pelvic engagement of the fetal head, aberrant fetal position, oligohydramnios, and multifetal gestation. Corrective mechanical forces similar to those that gave rise to the deformation to reshape the deformed structures are often used and should take advantage of the rapid postnatal growth to correct form.

Antepartum amnioinfusion: a review

OBJECTIVE

Antepartum amnioinfusion is a relatively recent procedure introduced with fetal medicine techniques. It is usually indicated for severe oligohydramnios in order to avoid the related complications such as pulmonary hypoplasia, the deforming effects of oligohydramnios, variable fetal heart rate decelerations and intraventricular hemorrhage. Antepartum amnioinfusion is also employed to improve ultrasound visualization in cases with oligohydramnios. Our objective was to evaluate the benefits and complications related to this procedure which is still less commonly used compared to intrapartum amnioinfusion, and whose risks are therefore not well established.

STUDY DESIGN

Reports of study designs identified from searches of MEDLINE, PUBMED, the Cochrane Collaboration, specialized databases and bibliographies of review articles were identified. Studies in women who underwent amnioinfusion between 1987 and 2002 were included.

RESULTS AND CONCLUSIONS

Amnioinfusion seems to offer several benefits, in terms of both prenatal diagnosis and favorable perinatal outcome. Most clinical experiences report that amnioinfusion is safe, both for the mother and for the fetus. However, randomized control-group studies subdivided on the basis of the cause of oligohydramnios (e.g. premature rupture of membranes, fetal growth restriction, obstructive uropathy and renal agenesis) could help to determine the advantages and risks linked to this procedure. Prospective randomized studies should therefore be encouraged, to clarify any possible doubts regarding the procedure, before it can be introduced into routine practice in the management of oligohydramnios.

Transabdominal amnioinfusion treatment of severe oligohydramnios in preterm premature rupture of membranes at less than 26 gestational weeks

OBJECTIVE

To evaluate the efficacy of transabdominal amnioinfusion on feto-neonatal and maternal morbidity and feto-neonatal mortality.

METHODS

We studied 71 patients with preterm premature rupture of membranes (pPROM) at <26 weeks of gestational age. Thirty-four patients were managed expectantly and 37 underwent serial transabdominal amnioinfusion with saline every 7 days in case of persistent oligohydramnios.

RESULTS

Latency period pPROM delivery, week of delivery (26.0 vs. 22.4, p<0.001), neonatal weight (922 vs. 602, p<0.01) and the percentage of intrauterine fetal survival were higher in treated than in control groups (64.8 vs. 32.3%, p<0.01). In amnioinfusion-treated patients, we did not note a higher rate of complications from infection during both pregnancy and puerperium. In the amnioinfusion group, fluid loss within 6 h after infusion is the main variable in predicting pulmonary hypoplasia and neonatal survival.

CONCLUSIONS

Our data suggest that amnioinfusion seems to be a low fetal and maternal risk technique that modifies the natural history of pPROM, improving fetal intrauterine stay and survival.

Women with impaired glucose tolerance during pregnancy have significantly poor pregnancy outcomes

OBJECTIVE

This article tests the hypothesis that women with impaired glucose tolerance (IGT) have the same pregnancy outcomes as those of their counterparts with normal glucose tolerance.

RESEARCH DESIGN AND METHODS

From December 1998 to December 1999, 84 of 90 antenatal care base units (ACBUs) under the Tianjin Antenatal Care Network in China participated in the first screening program for gestational diabetes mellitus (GDM). A total of 9,471 pregnant women under the care of participating ACBUs were screened. Of the women screened, 154 were positive for IGT. Of the 154 women, 102 opted for conventional obstetric care. The comparison group was 302 women of normal glucose tolerance (NGT). The initial screening consisted of a 50-g 1-h glucose test, and was carried out at 26-30 gestational weeks. Women with a serum glucose > or =7.8 mmol/l were followed up with a 75-g 2-h oral glucose tolerance test. The World Health Organization's diagnostic criteria for GDM were used.

RESULTS

Women with IGT were at increased risk for premature rupture of membranes (P-ROM) (odds ratio [OR] 10.07; 95% CI 2.90-34.93); preterm birth (6.42; 1.46-28.34); breech presentation (3.47; 1.11-10.84); and high birth weight (90th percentile or 4,000 g) (2.42; 1.07-5.46); adjusting for maternal age, pregravid BMI, hospital levels, and other confounding factors.

CONCLUSIONS

The presence of IGT in pregnancy is predictive of poor pregnancy outcomes.

Preterm premature rupture of the fetal membranes complicated by oligohydramnios

Preterm premature rupture of the fetal membranes complicated by oligohydramnios may have significant impact and sequelae on pregnancy outcome. In this article the role of amniotic fluid in fetal development, especially lung development, is reviewed; complications resulting from oligohydramnios are outlined; and the evaluated therapeutics and management schemes are delineated.

An in vitro model and case report that used gelatin sponge to restore amniotic fluid volume after spontaneous premature rupture of the membranes

OBJECTIVE

The purpose of this project was to study an in vitro model for plugging membrane defects with gelatin sponge and to develop a method with which to use this material to treat premature rupture of the membranes.

STUDY DESIGN

Fetal membranes were fixed over the opening of a flask that was filled with saline solution and gelatin sponge. Defects of various sizes were created, and the usefulness of differing sizes of gelatin sponge to obstruct the defects was observed. This technique was then applied to a case of previable, spontaneous premature rupture of the membranes.

RESULTS

Fifteen amniotomies were performed in the in vitro model. The gelatin sponge obstructed all defects less than 7 mm in length, when pieces up to 1 x 1 cm in dimension (n = 8 amniotomies) were used. For larger defects or those defects with a complex shape (such as cruciate), gelatin sponge was not effective at arresting fluid loss (n = 4 amniotomies). An inspection of larger gelatin sponge pieces, after instillation through a 12-gauge angiocatheter, revealed 36% (15 of 42 pieces) of 1 x 1 - cm pieces remained intact. A case of spontaneous, previable premature rupture of the membranes was treated with this material. A favorable outcome was observed.

CONCLUSION

Gelatin sponge is successful at arresting the egress of fluid through membrane defects when smaller defects are present. Complex or larger linear defects may not be treated by this method alone and necessitate adjuvant therapies. This therapeutic strategy can be applied to cases of previable, spontaneous premature rupture of the membranes.