Complications & Cesareans | Oligohydramnios: Low Amniotic Fluid
When Koni Howard was 25 and pregnant with her second child, she sensed something wasn’t quite right. The Oak Ridge, Tenn., mother wasn’t gaining much weight, and at 36 weeks into the pregnancy, was continuing to measure small for the baby’s due date.
“Unlike my first baby, [my second child] hardly ever moved,” she says. “I had a feeling there might be a problem.”
Oligohydramnios is often the result of a tear or rupture in the amniotic membrane.
She just didn’t know what the problem might be. Despite numerous blood tests and non-stress tests, which tracked the number of movements made by the baby, Howard’s obstetrician didn’t find anything to cause major concern.
However, at 36 weeks into the pregnancy, an ultrasound showed low amniotic fluid levels. Howard was diagnosed with oligohydramnios, a condition in which the amniotic fluid surrounding the baby is below normal levels.
“I was extremely surprised,” Howard says, of both the diagnosis and what happened next.
Oligohydramnios – low amniotic fluids had already returned home after the ultrasound and expected to hear the results at her next appointment. “When the phone rang, I never suspected it would be my doctor,” she says. “I knew it was after 5 p.m. and her offices were closed. So when she told me, ‘I think we’re ready to have this baby,’ I knew something was up.”
By the time Howard located her husband, found a babysitter for their 3-year-old daughter and returned to the hospital, the news had started to sink in. “I wasn’t worried, even when the doctor told me there was hardly any fluid left for the baby,” she says. “I was just so happy that I’d finally get to meet my baby.”
It isn’t unusual for a pregnant woman to have low levels of amniotic fluid in the third trimester of pregnancy, according to Dr. Scott Roberts, an obstetrician at Wichita, Kan.-based Wesley Medical Center who specializes in high-risk pregnancies. Although Roberts adds, oligohydramnios is a condition that can be diagnosed any number of times during a pregnancy.
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 placenta that is not supplying enough blood to the baby.
Either way, it is a condition that can be lethal, because Baby needs adequate fluid to develop lungs.
“Without enough amniotic fluid, Baby can’t make the transfer from the umbilical cord to breathing air,” Roberts says. The lungs are in their greatest stage of development between 16 and 25 weeks, but each day they have to mature inadequate amniotic fluid means greater function.
For Howard, delivering her baby at 36 weeks didn’t pose a significant risk because of Baby’s lung development, she says. “The doctor told me [the baby’s] lungs should be fully developed and that she didn’t foresee any problems from delivering early,” Howard says.
Once oligohydramnios is diagnosed, decisions about the baby’s delivery need to be made. Often, this means weighing the risks of inducing labor versus leaving the baby in-utero until it reaches greater maturity. There is some variance in the medical community about when is “long enough,” Roberts says, but typically, if a baby has too little fluid near term, “it is reasonable to consider that baby will do okay if born.” For Roberts, that means waiting until 37 weeks. For others, it can mean delivering as early as 34 weeks, he says.
Howard gave birth to a healthy baby, Jessica, weighing little more than 5 pounds. Now at 3 years old, Jessica’s development is “right on track,” says Howard. “She is sharp as a tack.”
Like many others who experience oligohydramnios, Howard didn’t have the complication when she became pregnant two years later with her third child.
According to the American Journal of Obstetrics, pregnant women who find themselves diagnosed with oligohydramnios should pay particular attention to eating a balanced diet and receiving regular prenatal care.
“The best treatment is good care,” Roberts says.