Oligohydramnios

When Amniotic Fluid is Too Low

By Laurie Dove

Oligohydramnios is often the result of a tear or rupture in the amniotic membrane, causing it to leak amniotic fluid and thus lower the level of fluid still surrounding the baby. If the low fluid levels are caused by a membrane leak, there is an increased risk of infection to both mother and baby, Roberts says. For baby, too little fluid can mean a tangle with an umbilical cord; without fluid to float in, a baby may sit on the cord and cut off its own blood supply. The mother also is vulnerable to bacteria that enter the uterus through the tear causing the fluid leak.

Low fluid levels can also complicate baby's delivery. With low levels, there is an increased risk of fetal heart decelerations in labor, Roberts says. Often, if baby is nearing full term, obstetricians will induce labor, as in Howard's case. If the baby is allowed to remain in the uterus, especially past term, the risks are even greater.

While in labor, a doctor may replace the lost fluid by infusing warm saline into the uterus. This decreases the risk of fetal distress. However, cautions Roberts, oligohydramnios can be the sign of more serious problems, such as a baby with kidney disease. A large part of the amniotic fluid is comprised of baby's urine and if low levels are not caused by a membrane leak, it means not enough amniotic fluid is being manufactured by the baby's kidneys or that it is not being released by the bladder and urethra.

"It could be that baby is not making much fluid or there is an obstruction in the urinary tract," Roberts says.

According to the American Journal of Obstetrics and Gynecology, other more serious causes can include a congenital heart defect, or uterine placnta that is not supplying enough blood to baby.

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