Continuing challenges in treating preterm labour: preterm prelabour rupture of the membranes
Prof H Helmer, Department of Obstetrics and Gynaecology, University of Vienna General Hospital, Wahringer Gurtel 18–20, A-1090 Vienna, Austria. Email firstname.lastname@example.org
Preterm prelabour rupture of the membranes (PPROM) is defined as prelabour rupture of the membranes prior to 37 weeks of gestation. It occurs in approximately 3% of pregnancies and is responsible for one-third of all preterm births. Effective treatment relies on accurate diagnosis, and it is gestational age dependent because the potential complications change with gestational age. Diagnosis itself is made by clinical suspicion, patient history and simple testing. Studies have shown that if a combination of patient history, nitrazine testing and ferning was used, the accuracy of at least two positive tests was 93.1%. PPROM is associated with significant maternal and neonatal morbidity and mortality from infection, umbilical cord compression, placental abruption and preterm birth. Subclinical uterine infection has been implicated as a major aetiological factor in the pathogenesis and subsequent morbidity associated with PPROM and antenatal antibiotics, together with corticosteroid therapies, have clear benefits and should be offered to all women without contraindications. Women with PPROM after 32 weeks should be considered for delivery, and after 34 weeks of gestation the benefits of elective delivery appear to outweigh the risks. Here, two cases are discussed that were experienced in our unit.
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Case study 1: preterm prelabour rupture of the membranes in early gestation (<24 weeks)
A 25-year-old primigravida was admitted to the hospital after preterm prelabour rupture of the membranes (PPROM) at 21 weeks + 4 days with regular contractions and closed cervix. There were no clinical symptoms of chorioamnionitis, no placental abruption. Sonography showed anhydramnios. Consultation was carried out together with the neonatologist in our unit.
The results of the main clinical studies, such as Epidemiological project for ICU Research and Evaluation (EPICure),1 and their implications were explained to the patient. In the Epidemiological project for TCU Research and Evaluation (EPICure)1 study, neurological and developmental disability after extremely preterm birth (22–25 weeks) was observed in 49% of babies evaluated after 30 months. Among the babies admitted to the neonatal intensive care unit (16% of those born at 22 weeks), only 1% survived until discharge. Of those born in the 23rd week, 54% were admitted to the neonatal intensive care unit and only 11% survived and were discharged.3 Other authors have concluded that expectant management of PPROM offers better perinatal and long-term survival than previously believed.2 Of ten infants born following successfully managed PPROM occurring between the 14th and the 19th week, four were alive 5 years later and available to assess. In this case, three of the four had survived without any major impairment, including neurological impairment. In addition to the results of the large controlled studies, paediatric data from our own institute were also discussed. It is necessary to refer to the local guidelines regarding comfort care following delivery. In Germany, intervention is mandatory if there is even a small chance of survival.
Counselling should be as objective and consistent as possible, and care should be taken not to be driven solely by experiences of recent cases. In an early case such as this (up to 22 weeks + 6), we also offer active pregnancy termination after careful counselling.
The possible strategies available to the parents in our case were antibiotics, tocolysis and any means of full diagnosis, which is possible including amniocentesis; antibiotics alone; or induction of delivery. The parents decided to proceed with the first option. At 24 weeks, steroids were given, and the pregnancy continued. At 25 weeks + 2, an elevated C-reactive protein count was found, and the patient went into labour. The next day, a female infant was delivered vaginally with a birthweight of 632 g.
The baby was admitted to the neonatal intensive care unit for mechanical ventilation. Surfactant was given to the baby on day 10. She developed a grade 2 intraventricular haemorrhage. Necrotising enterocolitis developed 25 days after delivery. Surgery was performed, and 3 days later, the baby died following severe sepsis and pulmonary oedema.
Case 2: PPROM in early gestation (≥24 weeks)
A 32-year-old woman who had experienced a previous preterm birth was admitted following PPROM at 27 weeks + 5. Contractions were regular, and the cervix dilated to 3 cm. There were no clinical symptoms of chorioamnionitis. Sonography showed oligohydramnios with an amniotic fluid index of 4.6 cm.
The woman was treated routinely with antibiotics, tocolytics and steroids. Amniocentesis was performed. Ureaplasma spp. was detected in culture and was treated with clarithromycin, which is known to cross the placenta more effectively than erythromycin. At 29 weeks, there was still oligohydramnios but no signs of chorioamnionitis, and again the woman developed contractions.
The possible treatment strategies were (a) to await delivery or expedite delivery; (b) tocolysis, followed by a second course of corticosteroids and then let the patient deliver and (c) to prolong the gestation as long as possible.
The woman opted for delivery. The baby weighed 1752 g with a 5-minute Apgar score of 9 and an arterial pH of 7.3. The baby was admitted to the neonatal intensive care unit where it developed respiratory distress syndrome and received continuous positive airway pressure for 5 days. Artificial surfactant was administered, but there was a late onset of sepsis 8 days later. Finally, a healthy baby was transferred to intermediate care and was later discharged.
For women with PPROM in early gestation, it is important to carry out objective and consistent counselling, using evidence from large-scale studies and experience from your own institution where possible. It is also useful to determine the amount of amniotic fluid and use diagnostic tools to determine infection status and intervene where appropriate. In contrast, if there is severe oligohydramnios compared with anhydramnios, the outcome may be very different. Park et al.3 have shown that with an amniotic index of 5 cm as a cutoff, there is a 42 versus 18% possibility of having positive cultures. In addition, the number of days gained until delivery is much greater if the amniotic fluid index is higher. This is also an important factor to take into account, and should be conveyed to the patient during counselling.