This leaflet is to help you understand what Pulmonary Hypoplasia is, what tests you need, and the implications of being diagnosed for you, your baby, and your family.

What is a pulmonary hypoplasia induced by oligohydramnios?

Underdevelopment of the fetal lungs (pulmonary hypoplasia) secondary to a severe reduction in the volume of amniotic fluid (oligohydramnios) caused by premature rupture of the membranes or fetal problems that affect the urinary tract of the fetus.

How does pulmonary hypoplasia induced by oligohydramnios occur?

A critical amount of amniotic fluid volume appears to be vital for proper lung development. The lack of fetal amniotic fluid is an indicator of reduced fetal voiding and /or renal function. It is also associated with the development of pulmonary hypoplasia.

How can I know if my baby has pulmonary hypoplasia?

The most common way to suspect pulmonary hypoplasia is if decreased amniotic fluid is found on routine ultrasound. Counseling depends on a series of questions to determine the cause of the reduced amniotic fluid.

Should I have more tests done?

Oligohydramnios is associated with many conditions/complications of pregnancy, and the differential breaks down into the following categories: maternal, fetal, placental, and idiopathic. A detailed medical history, physical examination with speculum and ultrasound scanning can help us in most cases to determine the cause of the decrease in amniotic fluid.

What are the things to watch for during the pregnancy?

Depending on the cause that can be identified that puts the baby at risk of pulmonary hypoplasia is the follow-up. In some cases, maternal hospitalization is recommended for intense monitoring as well as the use of antibiotics and laboratory tests.

What does it mean for my baby after they are born?
The prenatal prediction of pulmonary hypoplasia is important for perinatal management and
parental counseling, particularly in cases that will require intensive respiratory therapy immediately after birth. It mainly depends on the cause of oligohydramnios and the weeks at the time of diagnosis.

Preterm rupture of membranes (PROM) before fetal viability is a rare complication of pregnancy, but carries significant maternal morbidity, neonatal morbidity, and neonatal mortality. IF you develop this complication, you will need extensive counseling regarding the risks and benefits of conservative management. If you are undergoing conservative management of PROM before the limit of viability, serial assessments should be performed for signs of infection or labor. In addition, interval ultrasound examinations should be performed to assess for pulmonary hypoplasia. If these conditions arise, then conservative management may no longer be desirable. Limited data are available to guide the use of antenatal therapies such as antibiotics and corticosteroids to improve outcomes. Genetic studies may be advised by your doctor.

Will it happen again?

Recurrence risk depends primarily on the cause of oligohydramnios.

What other questions should I ask?

  • How often will I have ultrasound examinations done?
  • Is it possible to have an infection if I have a premature rupture of membranes?
  • Is a lethal malformation causing the fluid depletion?
  • Where should I deliver?
  • Where will the baby receive the best care after they are born?
  • Are there tests that help if there is doubt in the diagnosis of decreased amniotic fluid?

Last updated: July 2022