What is an Amnioinfusion?

Amnioinfusion is an obstetrical technique that may be employed at different stages of labor or pregnancy to address a variety of complications. The procedure adds fluid to the amniotic fluid, and it may do so in a couple of ways. Most often this addition of fluid is indicated when a woman is in labor and meets certain conditions, but there are a few times when it might be employed during pregnancy.

The more accepted recommendations for amnioinfusion are that it be used during end stages of labor. Normally, doctors will consider it if there are variable decelerations of the heartbeat, which might suggest cord compression. Adding extra fluid to the uterus is thought to give greater cushioning and potentially reduce chance of fetal cord compression, which in turn may make heart rate stable or prevent oxygen loss.

Another use of amnioinfusion during labor is suggested when concern exists that the baby will swallow meconium, or in utero waste produced by the fetus. This can cause problems post delivery, and it’s thought that use of extra fluid has a diluting effect on meconium and lowers risk of this occurring. Alternately, some doctors recommend that amnioinfusion, for women with low levels of amniotic fluid (oligohydramnios), is useful during labor and delivery.

Additional recommendations for this procedure exist, though not all are equally endorsed. Some believe that pregnant women with oligohydramnios should have extra fluid placed in the uterine sac prior to labor. Sometimes when women have prematurely ruptured membranes, amnioinfusion may be tried to stabilize uterine environment and avoid pre-term labor.

Exactly how this procedure works may depend on when it takes place. When the uterine sac is not ruptured and the infusion is given earlier in pregnancy, the typical method for getting fluid in would be similar to that used for amniocentesis. In cases where ruptured membranes have occurred and labor is fairly imminent, fluid is given by catheter directly into the uterus.

During labor, amnioinfusion may be undertaken with membrane rupture, since access to the uterus is thus gained. This step is unnecessary if the bag of waters is already broken. Most medical texts strongly recommend that adding extra fluids be performed concurrent with fetal scalp monitoring, though this may already be in place.

Extra fluid infusion is one way that doctors may be able to provide women with a more natural birthing environment. When heart decelerations occur, the natural impulse may be to recommend c-section. Instead, amnioinfusion could be attempted, though too many heart irregularities suggest safer delivery means, such as surgery.

Since this procedure is still not performed everywhere, and has really only been investigated since the 1980s, not all physicians favor it. More importantly, risks of amnioinfusion aren’t fully defined, but medical literature suggests they do exist. Those who may need to undergo this procedure should plan to talk with doctors about risks/benefits and determine the best course based on a physician’s answers about the most current studies.