Causes of pulmonary hypoplasia include a wide variety of congenital malformations and other conditions in which pulmonary hypoplasia is a complication. These include congenital diaphragmatic hernia, congenital cystic adenomatoid malformation, fetal hydronephrosis, caudal regression syndrome, mediastinal tumor, and sacrococcygeal teratoma with a large component inside the fetus. Large masses of the neck (such as cervical teratoma) also can cause pulmonary hypoplasia, presumably by interfering with the fetus's ability to fill its lungs. In the presence of pulmonary hypoplasia, the EXIT procedure to rescue a baby with a neck mass is not likely to succeed.

Fetal hydrops can be a cause, or conversely a complication.

Pulmonary hypoplasia is associated with oligohydramnios through multiple mechanisms. Both conditions can result from blockage of the urinary bladder. Blockage prevents the bladder from emptying, and the bladder becomes very large and full. The large volume of the full bladder interferes with normal development of other organs, including the lungs. Pressure within the bladder becomes abnormally high, causing abnormal function in the kidneys hence abnormally high pressure in the vascular system entering the kidneys. This high pressure also interferes with normal development of other organs. An experiment in rabbits showed that PH also can be caused directly by oligohydramnios.

Pulmonary hypoplasia is associated with dextrocardia of embryonic arrest in that both conditions can result from early errors of development, resulting in Congenital cardiac disorders.

PH is a common direct cause of neonatal death resulting from pregnancy induced hypertension.

Management has three components: interventions before delivery, timing and place of delivery, and therapy after delivery.

In some cases, fetal therapy is available for the underlying condition; this may help to limit the severity of pulmonary hypoplasia. In exceptional cases, fetal therapy may include fetal surgery.

A 1992 case report of a baby with a sacrococcygeal teratoma (SCT) reported that the SCT had obstructed the outlet of the urinary bladder causing the bladder to rupture in utero and fill the baby's abdomen with urine (a form of ascites). The outcome was good. The baby had normal kidneys and lungs, leading the authors to conclude that obstruction occurred late in the pregnancy and to suggest that the rupture may have protected the baby from the usual complications of such an obstruction. Subsequent to this report, use of a vesicoamniotic shunting procedure (VASP) has been attempted, with limited success.

Often, a baby with a high risk of pulmonary hypoplasia will have a planned delivery in a specialty hospital such as (in the United States) a tertiary referral hospital with a level 3 neonatal intensive-care unit. The baby may require immediate advanced resuscitation and therapy.

Early delivery may be required in order to rescue the fetus from an underlying condition that is causing pulmonary hypoplasia. However, pulmonary hypoplasia increases the risks associated with preterm birth, because once delivered the baby requires adequate lung capacity to sustain life. The decision whether to deliver early includes a careful assessment of the extent to which delaying delivery may increase or decrease the pulmonary hypoplasia. It is a choice between expectant management and active management. An example is congenital cystic adenomatoid malformation with hydrops; impending heart failure may require a preterm delivery. Severe oligohydramnios of early onset and long duration, as can occur with early preterm rupture of membranes, can cause increasingly severe PH; if delivery is postponed by many weeks, PH can become so severe that it results in neonatal death.

After delivery, most affected babies will require supplemental oxygen. Some severely affected babies may be saved with extracorporeal membrane oxygenation (ECMO). Not all specialty hospitals have ECMO, and ECMO is considered the therapy of last resort for pulmonary insufficiency. An alternative to ECMO is high-frequency oscillatory ventilation.

Baylor College of Medicine in Houston, Texas has conducted ACD research since 2001.

Several patients have survived with atypical or “patchy ACDMPV” long enough to receive lung transplants. According to a 2013 case series conducted by St. Louis Children’s Hospital, four ACDMPV patients (ages 4 months, 5 months, 9 months and 20 months of age at time of transplant) with atypical presentations of ACDMPV each underwent a successful bilateral lung transplantation (BLT). As stated in the case study, “If they survive to BLT, patients with ACDMPV can have successful outcomes” and the ACDMPV patients “are alive at last follow-up at 1, 8, 9 and 12 years of age” (as of May 2013).

According to the St. Louis Children's Hospital (the Level I pediatric trauma center and pediatric teaching hospital for the Washington University School of Medicine), which is noted worldwide for its record in pediatric pulmonary transplantation, a type of artificial lung device, the Quadrox, was used after ECMO as a bridge to a dual lung transplant in ten-month-old Eleni Scott of the St. Louis suburb of Florissant, Missouri, who after transplantation returned to her home. Doctors have said it is too early to presume it will continue to work here or work in other pediatric patients as an experiment, much less a successful, curative standard therapy, but the infant has survived thus far, meaning that there might be hope for sufferers of this rare condition. For more information, please see the link to the news release.

Acute respiratory distress syndrome (ARDS) has some similarities to IRDS. Transient tachypnea of the newborn presents with respiratory distress syndrome in the preterm newborn.

The outcome of Potter's Sequence is poor. A series of 23 patients in 2007 recorded 7 deaths, 4 in the neonatal period. All 16 survivors have chronic kidney disease, with half developing end stage renal failure (median age 0.3 years, range 2 days to 8.3 years). Survivors had growth impairment (44%) and cognitive and motor development delay (25%)

The first child to survive Bilateral Renal Agenesis (BRA), Abigail Rose Herrera Beutler, was born on July 2013 to US Congresswoman Jaime Herrera Beutler.

A few weeks before she was born, Dr. Jessica Bienstock, a professor of maternal-fetal medicine at Johns Hopkins Hospital, administered a series of saline solution injections into the mother's womb to help the baby's lungs to develop. After Abigail was born, the procedure was considered a success. The infant did not need artificial respiration and could breathe on her own. Her parents kept her on kidney dialysis at home until old enough for a kidney transplant. On February 8, 2016, at the age of two, Abigail received a kidney from her father at the Lucile Packard Children's Hospital Stanford in California.

Scimitar syndrome, or congenital pulmonary venolobar syndrome, is a rare congenital heart defect characterized by anomalous venous return from the right lung (to the systemic venous drainage, rather than directly to the left atrium). This anomalous pulmonary venous return can be either partial (PAPVR) or total (TAPVR). The syndrome associated with PAPVR is more commonly known as "Scimitar syndrome" after the curvilinear pattern created on a chest radiograph by the pulmonary veins that drain to the inferior vena cava. This radiographic density often has the shape of a scimitar, a type of curved sword. The syndrome was first described by Catherine Neill in 1960.

Congenital diaphragmatic hernia has a mortality rate of 40–62%, with outcomes being more favorable in the absence of other congenital abnormalities. Individual rates vary greatly dependent upon multiple factors: size of hernia, organs involved, additional birth defects, and/or genetic problems, amount of lung growth, age and size at birth, type of treatments, timing of treatments, complications (such as infections) and lack of lung function.

Potter sequence is the atypical physical appearance of a baby due to oligohydramnios experienced when in the uterus. It includes clubbed feet, pulmonary hypoplasia and cranial anomalies related to the oligohydramnios. Oligohydramnios is the decrease in amniotic fluid volume sufficient to cause deformations in morphogenesis of the baby.

Oligohydramnios is the cause of Potter sequence but there are many things that can lead to oligohydramnios. It can be caused by renal diseases such as bilateral renal agenesis (BRA), atresia of the ureter or urethra causing obstruction of the urinary tract, polycystic or multicystic kidney diseases, renal hypoplasia, amniotic rupture, toxemia, or uteroplacental insufficiency from maternal hypertension.

The term "Potter sequence" was initially intended to only refer to cases caused by BRA; however, it is now commonly used by many clinicians and researchers to refer to any case that presents with oligohydramnios or anhydramnios regardless of the source of the loss of amniotic fluid.

Giving the mother glucocorticoids speeds the production of surfactant. For very premature deliveries, a glucocorticoid is given without testing the fetal lung maturity. The American College of Obstetricians and Gynecologists (ACOG), Royal College of Medicine, and other major organizations have recommended antenatal glucocorticoid treatment for women at risk for preterm delivery prior to 34 weeks of gestation. Multiple courses of glucocorticoid administration, compared with a single course, does not seem to increase or decrease the risk of death or neurodevelopmental disorders of the child.

In pregnancies of greater than 30 weeks, the fetal lung maturity may be tested by sampling the amount of surfactant in the amniotic fluid by amniocentesis, wherein a needle is inserted through the mother's abdomen and uterus. Several tests are available that correlate with the production of surfactant. These include the lecithin-sphingomyelin ratio ("L/S ratio"), the presence of phosphatidylglycerol (PG), and more recently, the surfactant/albumin (S/A) ratio. For the L/S ratio, if the result is less than 2:1, the fetal lungs may be surfactant deficient. The presence of PG usually indicates fetal lung maturity. For the S/A ratio, the result is given as mg of surfactant per gm of protein. An S/A ratio 55 indicates mature surfactant production(correlates with an L/S ratio of 2.2 or greater).

Surgical correction should be considered in the presence of significant left to right shunting (Qp:Qs ≥ 2:1) and pulmonary hypertension. This involves creation of an inter-atrial baffle to redirect the pulmonary venous return into the left atrium. Alternatively, the anomalous vein can be re-implanted directly into the left atrium.

Congenital diaphragmatic hernia (CDH) is a birth defect of the diaphragm. The most common type of CDH is a Bochdalek hernia; other types include Morgagni hernia, diaphragm eventration and central tendon defects of the diaphragm. Malformation of the diaphragm allows the abdominal organs to push into the chest cavity, hindering proper lung formation.

CDH is a life-threatening pathology in infants and a major cause of death due to two complications: pulmonary hypoplasia and pulmonary hypertension. Experts disagree on the relative importance of these two conditions, with some focusing on hypoplasia, others on hypertension. Newborns with CDH often have severe respiratory distress which can be life-threatening unless treated appropriately.

The cause is not known but is often associated with some:

- fetal chromosomal anomalies

- intra uterine infections

- drugs; PG inhibitors, ACE inhibitors

- renal agenesis or obstruction of the urinary tract of the fetus preventing micturition such as posterior urethral valves in males

- intrauterine growth restriction (IUGR) associated with placental insufficiency

- "amnion nodosum"; failure of secretion by the cells of the amnion covering the placenta

- postmaturity (dysmaturity)

Treatment is symptomatic, often addressing indicators associated with peripheral pulmonary artery stenosis. Laryngotracheal calcification resulting in dyspnea and forceful breathing can be treated with bronchodilators including the short and long-acting β2-agonists, and various anticholinergics. Prognosis is good, yet life expectancy depends on the severity and extent of diffuse pulmonary and arterial calcification.

Known environmental factors include certain infections during pregnancy such as Rubella, drugs (alcohol, hydantoin, lithium and thalidomide) and maternal illness (diabetes mellitus, phenylketonuria, and systemic lupus erythematosus).

Being overweight or obese increases the risk of congenital heart disease. Additionally, as maternal obesity increases, the risk of heart defects also increases. A distinct physiological mechanism has not been identified to explain the link between maternal obesity and CHD, but both prepregnancy folate deficiency and diabetes have been implicated in some studies.

The cause of congenital heart disease may be genetic, environmental, or a combination of both.

The female homolog to the male verumontanum from which the valves originate is the hymen.

Complications may include cord compression, musculoskeletal abnormalities such as facial distortion and clubfoot, pulmonary hypoplasia and intrauterine growth restriction. Amnion nodosum is frequently also present (nodules on the fetal surface of the amnion).

The use of oligohydramnios as a predictor of gestational complications is controversial.

Potter syndrome is a condition caused by oligohydramnios. Affected fetuses develop pulmonary hypoplasia, limb deformities, and characteristic facies. Bilateral agenesis of the fetal kidneys is the most common cause due to the lack of fetal urine.

In a newborn boy thought to have Fryns syndrome, Clark and Fenner-Gonzales (1989) found mosaicism for a tandem duplication of 1q24-q31.2. They suggested that the gene for this disorder is located in that region. However, de Jong et al. (1989), Krassikoff and Sekhon (1990), and Dean et al. (1991) found possible Fryns syndrome associated with anomalies of chromosome 15, chromosome 6, chromosome 8(human)and chromosome 22, respectively. Thus, these cases may all represent mimics of the mendelian syndrome and have no significance as to the location of the gene for the recessive disorder.

By array CGH, Slavotinek et al. (2005) screened patients with DIH and additional phenotypic anomalies consistent with Fryns syndrome for cryptic chromosomal aberrations. They identified submicroscopic chromosome deletions in 3 probands who had previously been diagnosed with Fryns syndrome and had normal karyotyping with G-banded chromosome analysis. Two female infants were found to have microdeletions involving 15q26.2 (see 142340), and 1 male infant had a deletion in band 8p23.1 (see 222400).

Dextrocardia is believed to occur in approximately 1 in 12,019 pregnancies.

A Japanese study of 1,753 fetal cardiac echocardiograms over five years only revealed two cases.

Keutel syndrome is an autosomal recessive disorder caused by a novel loss-of-function mutation in the matrix Gla protein gene (MGP). MGP protein resides in the extracellular matrix and is implicated in inhibiting calcification though the repression of bone morphogenetic protein 2 (BMP2). Mutations resulting in loss of consensus donor splice site at exon 2-intron 2 junctions result in significant diffuse calcification of soft tissue cartilage. Extensive diffuse cartilaginous calcification is present in MGP-knockout mice, manifesting in vascular media replacement with a cartilaginous, chondrocyte-like matrix, and ultimately premature death. Conversely, over expression of extracellular MGP effectively abolishes calcification in chondrocytes, suggesting that MGP may function in inhibiting passive calcification in soft tissues. Recent evidence suggests MGP is a vitamin K dependent protein synthesized by chondrocytes and vascular smooth muscle cells, where it potentiates the inhibition of cartilaginous and arterial calcification. Thus, potential vitamin K deficiency, via nutritional deficiency or coumarin-derivative use, would render MGP uncarboxylated and inactive, thus diminishing biological function. Arterial calcification resulting from MGP inactivation results in inimical prognosis, commonly seen in patients with diabetes, atherosclerosis, and renal dysfunction.

In France, Aymé, "et al." (1989) estimated the prevalence of Fryns syndrome to be 0.7 per 10,000 births based on the diagnosis of 6 cases in a series of 112,276 consecutive births (live births and perinatal deaths).

Thymic hypoplasia is a condition where the thymus is underdeveloped or involuted.

Calcium levels can be used to distinguish between the following two conditions associated with thymic hypoplasia:

- 22q11.2 deletion syndrome: hypocalcemia

- Ataxia telangiectasia: normal levels of calcium

Dextrocardia with situs inversus refers to the heart being a mirror image situated on the right side. For all visceral organs to be mirrored, the correct term is dextrocardia situs inversus totalis.

Although statistically people with dextrocardia do not have any medical problems from the disorder, they may be prone to a number of bowel, esophageal, bronchial and cardiovascular disorders (such as double outlet right ventricle, endocardial cushion defect and pulmonary stenosis). Certain cardiovascular and pulmonary disorders related to dextrocardia can be life-threatening if left unchecked (see reference).

Kartagener syndrome may also be present in patients with dextrocardia but this must be in the setting of situs inversus and may include male infertility.

3C syndrome, also known as CCC dysplasia, Craniocerebellocardiac dysplasia or Ritscher–Schinzel syndrome, is a rare condition, whose symptoms include heart defects, cerebellar hypoplasia, and cranial dysmorphism. It was first described in the medical literature in 1987 by Ritscher and Schinzel, for whom the disorder is sometimes named.