Successful outcome of a preterm infant with severe oligohydramnios and suspected pulmonary hypoplasia following premature rupture of membranes (PPROM) at 18 weeks’ gestation

Introduction

About 3–4.5% of pregnancies can be complicated by preterm premature rupture of the membranes (PPROM) and approximately one-third of all preterm births are associated with PPROM. Studies in the United States have shown the incidence of PPROM between 16 and 26 weeks of gestation at 1%. Other studies have reported mid-trimester pre-labor PPROM before 26 weeks of gestation at 0.5–1% of all pregnancies and is associated with poor perinatal outcome [1], [2], [3], [4], [5]. In spite of all recent advances in maternal and newborn care, such pregnancies still pose a great risk to both the mother and baby. Though chorioamnionitis leading to sepsis is the biggest maternal risk, other potential complications are preterm delivery, increased chance of cesarean section and postpartum infection. The neonatal complications are dependent on the time of the PPROM and the degree of oligohydramnios predisposing to consequences such as pulmonary hypoplasia and fetal deformities in addition to risk of infection from PPROM. An important aspect of the overall management is the antenatal counseling with a collaborative approach, providing a realist picture and taking a judicious decision between expectant management or active intervention for the best possible maternal and neonatal outcome [2], [4], [6].

Case presentation

This baby girl was born at 32 weeks of gestation to a 21-year-old gravida 4, para 3 woman. This pregnancy was spontaneously conceived with a normal first trimester ultrasound study. All her serologies were protective. There was no history of hypertension or gestational diabetes mellitus. She smoked up to one packet of cigarettes per day throughout the pregnancy. Pregnancy was uneventful until 18 + 2/7 weeks of gestation when there was suspected leaking of amniotic fluid due to rupture of membranes along with some possible spotting. The leakage continued for 2 days before slowing down, although she continued to have intermittent leakage during certain situations like coughing. The patient did make any hospital visit at that time and came only for a follow-up ultrasound examination at 22 weeks which revealed oligohydramnios with amniotic fluid index (AFI) of 3 cm and a maximal vertical pocket (MVP) of 1.4 cm. A pericardial effusion measuring approx. 3.9 mm was also noted at that time. The fetus was in breech position with an estimated fetal weight of 451 g. At 23 + 4/7 weeks, the patient was admitted for PPROM/oligohydramnios, placenta previa, and fetal pericardial effusion. There was no evidence of chorioamnionitis. The TORCH study done to assess for possible infection in view of fetal pericardial effusion was negative. The ultrasound examination again showed oligohydramnios with AFI of 1.9 cm and MVP of 1.9 cm. Q1 1.9 cm, Q2 0.0 cm, Q3 0.0 cm, Q4 0.0 cm. There was also an inadequate growth of the fetus with an estimated fetal weight of 559 g. A maternal-fetal medicine (MFM) consultation was done and the recommendation was conservative management and immediate delivery if there was any concern for chorioamnionitis. Antibiotic coverage, as well as a course of antenatal betamethasone, was given. The neonatology consultation done at 23 + 5/7 weeks of gestation reiterated concerns of significant neonatal mortality and morbidity associated with such severe chronic oligohydramnios along with extreme prematurity. The parents, however, continued their wish for full support for their baby. Repeat ultrasound examination at 25, 27 and 31 weeks continued to show oligohydramnios and breech position of the fetus. At 32 weeks of gestation, the baby was delivered by cesarean section for preterm labor with breech and PPROM. The baby was appropriate for gestational age (GA) with a birth weight of 1.51 kg. She required positive pressure ventilation (PPV) for 1 min and was then started on nasal continuous positive pressure ventilation (nCPAP) with a pressure of 7–8 cm. Maximum oxygen requirement was about 30%. APGAR scores were 1 and 7 at 1 min and 5 min, respectively with a normal cord gas. The chest X-ray examination showed a significant right-sided pneumothorax (Figure 1).

Figure 1:

Chest X-ray A–P view after the development of a right-sided pneumothorax.

The pneumothorax was relieved by chest tube insertion (Figure 2). The baby remained on non-invasive ventilation (NIV, nCPAP) during the entire stay in the neonatal intensive care unit (NCIU). Respiratory support was discontinued on day 5 and the baby remained in room air until discharge. The chest tube was removed 48 h later (Figure 3). The other supportive care included caffeine and systemic antibiotics. The baby was finally discharged home on day 24 of life at a corrected gestation age (CGA) of 35 + 4/7 weeks and weight of 1.93 kg.

Figure 2:

Chest X-ray A–P view showing chest tube on the right-side with the resolution of the pneumothorax.

Figure 3:

Chest X-ray A–P view showing resolution of the right-sided pneumothorax, after chest tube removal.

Discussion

Management of early PPROM is a big challenge and poses a great risk to both the mother and the baby. Although the last few decades have seen significant advances in both obstetric and neonatal care with the use of intrapartum antibiotics, antenatal steroids, surfactant and newer ventilation strategies, but the potential adverse outcomes for both mother and infant with PPROM still continue to be significant.

The maternal risk for chorioamnionitis have been reported to be between 20 and 70% following PPROM and is not related to the time at which PPROM occurs. Interestingly, development of sepsis due to chorioamnionitis is not very common. But the mothers are at increased risk of preterm birth, placental abruption, cesarean delivery, prolonged antenatal hospitalization and postpartum infection [7], [8]. The time from rupture of membranes to delivery is also variable. Approximately 75% of women deliver within 1 month of PPROM and that the remaining 25% remain pregnant beyond 1 month [1], [7]. The most significant effect on the fetus is pulmonary hypoplasia – the incidence and severity are related to the GA at PPROM. The earlier the onset, the higher the incidence. However, the possibility of liquor re-accumulation and uncomplicated neonatal survival does exist. We suspect that this likely occurred in this mother on an intermittent basis, sufficient enough to allow reasonable pulmonary growth and development despite some evidence of pulmonary hypoplasia as indicated by relatively small volume lungs and pneumothorax. Neonates born following early PPROM are at risk of mortality and morbidities due to pulmonary hypoplasia, air leaks and chronic lung disease in addition to sepsis [1], [3].

Counseling women who present with PPROM at pre-viable GA is challenging. Many of these women will go into spontaneous labor or would need to be delivered at a pre-viable GA due to maternal health risks. Fetal risks are mainly determined by the effect of the prolonged oligohydramnios on lung development, possible infection and need to be weighed against the benefit of increased maturity when considering expectant management. Thus, counseling of patients with mid-trimester PPROM remains challenging and it is important to provide a realistic picture to the parents [4], [7], [9].

Given the risks and uncertainties, a very poor prognosis for the neonate is often presented to the patient. However, studies have shown that in some women with PPROM at a pre-viable GA and continuing their pregnancy to reach a viable GA, there was 76% survival to discharge for the group of preterm infants born at <32 weeks [1]. Another study found that the overall predicted survival rate was between 23 and 54% in PPROM occurring in the early second trimester (<24 weeks’ gestation) [8].

Our case shows that though early rupture of membranes poses a significant risk to both the mother and baby, the successful outcome indicates a possible intermittent re-accumulation of fluid facilitating lung growth, even though antenatal ultrasounds always demonstrated severe oligohydramnios.

Take home messages:

1. Mid-trimester PPROM before 26 weeks of gestation have been reported to occur in approximately 0.5–1% of all pregnancies and is associated with poor perinatal outcome.

2. There is a significant maternal risk for chorioamnionitis and neonatal risk for pulmonary hypoplasia.

3. Counseling for such patients is challenging and is important to provide a realistic picture to the parents.

4. Severe oligohydramnios due to PPROM may not always indicate a poor prognosis as intermittent fluid re-accumulation is possibly facilitating fetal lung growth which might not always be accurately defined during ultrasound examination.