Birth Story #388: An Effective Amnioinfusion

Photo (c) iStockPhoto

The widely-used practice of continuous fetal monitoring during labor has been criticized as a contributor towards the increase in operative deliveries via vacuum, forceps and Cesarean section.  Available evidence suggests that continuous fetal monitoring does not improve neurologic outcomes in newborns, and even ACOG states either continuous or intermittent fetal monitoring are acceptable in low-risk pregnancies.  Despite these recommendations, many busy Labor & Delivery units rely upon continuous fetal monitoring because they do not have the nursing staff to perform the check and rechecks necessary for adequate intermittent monitoring.  In my practice, I prefer intermittent fetal monitoring because it permits the laboring woman greater freedom of movement and because it minimizes the chance I will see an isolated abnormality on the fetal monitor that might compel me to use unnecessary interventions.

However, sometimes I have to use continuous monitoring when a woman presents with a higher-risk condition of pregnancy such as gestational diabetes, or if her initial fetal monitor tracing (commonly called "the strip") is abnormal.  I do everything I can to avoid interpreting the strip in a way which might lead the woman down the path to an operative delivery, even if it means I have to chew my nails to the quick until the baby is safely born.  Here is one such tale.

Yadira was a 24 year-old second-time mother.  She'd immigrated from Mexico two years earlier, leaving her daughter in the care of her own mother so she could find a decent-paying job.  By the time I met her, the family was reunited and Yadira was pregnant again.  What might have been a time of celebration to some young women was an extremely stressful transition for Yadira.  Her boyfriend abandoned her and she was compelled to move in with a cousin and his extended family.  Eight adults and three children shared a one-bedroom apartment, and all the adults worked manual labor jobs, including Yadira. 

When she entered her last month of pregnancy, she left her job because her back hurt all the time and her feet swelled up severely after a long day of standing at work.  She was not eligible for disability payments, so leaving work meant she had no income at all.  Instantly the dynamic at home changed; conflicts arose because she was no longer contributing money to the household regularly.  Yadira gave up all her savings to keep her place in the home, but this left her with no money to get supplies for the new baby.  I brainstormed with the clinic staff to pull together some basic supplies such as a car seat, some simple baby clothes and receiving blankets, a sleeper cot, and an initial supply of diapers.  All the recent mothers in the clinic contributed, as did the owner of a local second-hand babywear shop.  We have a great community up here, we really do.  Yadira was really grateful for the contributions but still worried about money. 

"Doctora, will you provoke my pains if I don't have my baby this week?" she asked me as the approached her due date.

"Why do you want to provoke labor?" I asked, echoing the commonly-used term in Spanish for induction of labor.

"Because I must go back to work in three weeks," she said.  "If not, I will have to leave my home."

There was no medical reason to induce Yadira, so I reassured her we'd re-address the issue if she went significantly overdue.  I examined her cervix--she was 2-3 centimeters but not very effaced.  I stripped her membranes, which occasionally brings on adequate contractions and can kick-start a woman's labor if her body is truly ready.

Well in Yadira's case, it worked like a charm.  The next morning, as I started my call day, Labor & Delivery called me to announce Yadira was in labor.  "She's four centimeters and contracting every three to four minutes," said Stace, one of the nurses on duty.  "She's doing really well, but I'm worried about her strip."

Before I continue with Yadira's story, I'm going to review Fetal Heart Monitoring 101.  When I woman arrives in labor at a hospital, part of the initial assessment is at least 20 minutes of continuous monitoring to determine what the pattern of fetal heart tones (FHTs) show.  Two plastic monitors are applied to the woman's abdomen, one to detect contractions, one to detect fetal heart rate.  A common mnemonic for interpreting the initial 20 minute monitoring period is DR. C. BRAVADO:

DR=Determine risk, including assessment of  pre-pregnancy health conditions or abnormalities arising during pregnancy

C=Contractions.  Are these detected with the external monitors?

BR=Baseline rate.  An individual fetus tends to settle into a baseline heart rate between 120-180 beats per minute.  The minimum 20 minute monitoring period is necessary to determine an accurate baseline heart rate.

A=Accelerations.  These are defined as an increase of at least 15 beats over baseline which lasts for at least 15 seconds.

VA=Variability.  This is defined as the smaller variations in the fetal heart rate which don't meet the definition of acceleration or deceleration but which should be present throughout a continuous strip.  The presence of adequate variability suggests fetal well-being, or adequate oxygen delivery to the fetus.

D=Deceleration.  This is defined as a significant decrease from the baseline heart rate.  Early decelerations are bowl-shaped and occur in sync with the uterine contraction.  These represent compression of the fetal head by the contraction and are considered benign.  Variable decelerations are V-shaped and occur in sync with the uterine contraction.  These represent compressions of the umbilical cord and are usually benign but, if the decrease from baseline is significant and the variables persist for a long period of time, they can result in the development of more concerning fetal heart tracings.  Late decelerations are bowl-shaped and reach their lowest point after the uterine contraction has resolved.  These represent insufficient blood flow through the placenta and, if they occur regularly, are very worrying for fetal compromise.

O=Overall impression.  Medical students are encouraged to develop a conclusion to their assessments.  After summarizing the individual findings on a strip, the person interpreting it should decide whether the strip is reassuring for fetal well-being, or nonreassuring.

Here is an example of a reassuring strip, hand-drawn by me in photo editing software, so please forgive the quality of the image:

As you can see, the fetal heart tones do not dip below baseline except for a couple of seconds at most, and there are at least two accelerations present.  The variability appears adequate (squiggly quality of line) and the woman is contracting regularly.  This is what I call a dream strip and I would not agonize over the condition of this baby at this point in labor.

Now, back to Yadira's story.  Because Stace was concerned about Yadira's strip, I went to Labor & Delivery immediately to see for myself.  When I entered the labor room, I saw Yadira lying on her side, breathing through a contraction.  She winced at the peak of the intensity, but looked strong and beautiful the way some women do when in labor.  Then I turned to the fetal monitor next to the labor bed.  This is what her strip looked like:

Obviously she was contracting regularly, and the overall variability of the strip looked OK, but she was having moderately severe variable decelerations with each contraction.  Because her labor looked good and hard, I wasn't worried about the variables per se.  What bothered me was the delay in returning back to the baseline heart rate.  As you can see if you look closely at the illustration, the contraction ends but the heart tones are still below the baseline (black line).  Sometimes this happens because there is an element of placental insufficiency, but I've also seen this when the cord is wrapped bandolier-style around the baby's shoulder and arms, or around the leg.  In any case, this pattern of heart tones is moderately concerning, and I have been told that, at some very aggressive hospitals, a woman might be counseled to have a C-section, even though there is no evidence supporting immediate delivery in this situation.

I verified the fetal heart pattern by applying a fetal scalp electrode.  I don't use these routinely but, if there is concern for the well-being of the baby I will use all available technology.  The internal monitor verified the presence of moderate variables with late return to baseline, so I decided to start an amnioinfusion to help resolve the variable decelerations. 

An amnioinfusion is the delivery of crystalloid solution into the uterine cavity via an intrauterine pressure catheter (IUPC), which is a tube introduced through the cervix and left in place next to the fetal head.  The rationale for this intervention is to introduce a fluid buffer around the umbilical cord, which is being compressed by the force of contractions.  I was trained to use amnioinfusion whenever persistent moderate or severe variables are present, and I have found it helps a lot in at least 80% of cases, so it is always worth a try.

Stace began the amnioinfusion while I kept a close eye on Yadira and her strip.  I ended up staying in the room because Yadira only spoke Spanish and none of the nurses working that day could communicate well with her.  Just as well, because as the amnioinfusion was going in, Yadira's labor pattern intensified.  I could tell by the measurement of the IUPC but even more from her face and her posture.  Her breaths got deeper and deeper and I could see the surface of her belly getting shiny from the force of the underlying contractions.  As the force of the contractions increased, the variable decelerations got deeper and deeper too, and took longer to return to baseline.  I didn't like it.  At one point, the heart tones dipped all the way to 70 and took four minutes to get back to the baby's baseline of 140 beats per minute. 

I believed the amnioinfusion would be effective but I wouldn't see the results for at least an hour after the liter of fluid was in.  I knew if I consulted the obstetrician of the day, he'd recommend a C-section because he does not use amnioinfusion in his practice.  Yadira had a successful vaginal delivery in the past and I was bound and determined for her to have another one, if only the baby's heart tones would cooperate.

At the next steep variable, I had Yadira roll onto her hands and knees.  This can help optimize circulation to the placenta, and indeed, she had no more dramatic prolonged decels in that position.  The variables continued, however, and I explained to her that I wanted her to stay on hands and knees to help the baby's circulation and she was okay with the advice.  I also had an oxygen mask over her face, and encouraged deep breathing.  Throughout these maneuvers, I kneeled on the floor next to her so I could keep my face near hers and our communication could be clear, despite the noise of the monitor, the oxygen, and Yadira's own labor efforts.

We stayed like that for an hour and a half.  I know because I reviewed her entire strip later in the day, including my notations on the progress of labor and the interventions we were making.  An hour and a half with Yadira on her hands and knees in bed, and me on my knees on the floor, and finally--the variables resolved, and there were no late decels hiding behind the original pattern.

At this point, Yadira was eight centimeters dilated and feeling a slight urge to push.  I had her hum and grunt gently with contractions, and then she was complete.  She pushed for twenty minutes, during which time the baby's heart tones looked perfect, and gave birth to a beautiful boy, who weighed in at eight pounds and ten ounces and had umbilical cord wrapped around his shoulders and left leg.  She was delighted, and I was profoundly grateful for the wonders of amnioinfusion. 

Next time, though, I'm bringing knee pads.

Comments

[Theresa]

Hi Rixa: If there is truly thick meconium, I will amnioinfuse to dilute the mec but the current thinking on mec aspiration is that most of it probably takes place before fetal descent. I amnioinfuse mainly for steep variables if the birth is not likely to happen within a short interval. I have occasionally amnioinfused when there was some other reason for concern on a continuous strip, just because I think it removes the element of cord compression from the interpretation and you can see if there is really anything there to be worried about or not. Amnioinfusion means an IUPC and many women don't want internal monitoring, but I really think we've prevented a bunch of C-sections with judicious use of IUPC/amnioinfusion.

At our Labor & Delivery, frequent position changes are encouraged, especially during labor. Many women have read up about the benefits of moving freely while in labor, but it is important to recognize that some women really don't want to move much (this is a good reason to encourage childbirth education, imho). I will say a lot of women end up pushing in some variation of lithotomy and a common belief among our nurses is that this is actually a good position for pushing. I don't encourage or insist upon lithotomy, and I estimate the proportions of women who birth in lithotomy versus "unorthodox" positions (standing, H&K, squatting, in the tub, kneeling) is close to 50-50.

I have to say I love it when I woman give birth kneeling. This position centers the belly, helps the baby rotate into an adaptive position, and it is easier to hand the baby up into its mother's arms from a kneeling position than, say, H&K.

I'm also looking into using yoga headstand supports as birthing stools but I have to talk to our L&D nurse manager about this.

[Rixa]

This was an interesting birth story. I just looked up amnioinfusion on the Cochrane database and it seems like it can be beneficial for certain circumstances. What other situations besides the one you encountered at this birth might you recommend it?

I think another great learning point from this story is the importance of using different positions for laboring and birthing, especially ones that enhance blood flow to the baby. Is laboring on H&K (or other "unorthodox" positions) fairly common/accepted in your hospital among the other doctors or midwives?

[T.]

Theresa, I am profoundly impressed by the way you stood by this patient during her labor. At many institutions this would have definitely gone to C-section...it is indeed refreshing to see your hard work result in avoiding that.

[Theresa]

Jasmine,

I don't remember exactly when Yadira SROM'd but I believe it was at the onset of labor because it was the reason she went to L&D. I didn't AROM in her case.

[Jasmine]

Congrats on a good (if anxiety-inducing) birth.

I'm hoping you won't mind answering a question that I'm curious about - when did her water break? It wasn't included in the birth story. Thanks if you have time to reply.

[mommymichael]

Hi there. I can't remember if I've ever commented before, but I must say that I love your persistence for a vaginal birth and of course a safe birth period. I work as a doula and a Hypnobabies (hypnosis for childbirth) instructor in my area and I hardly ever see anything like what you do for the mothers in your birth stories. More often then not if a mother is wanting a natural birth she has to put up quite a bit of a fight to get even the simplest request.

Thank you from the bottom of my heart. It's refreshing and encouraging.