QuestionQUESTION: Hi, I am 35 weeks pregnant. Today during my non-stress test, the baby had mild variable decelerations during the first contraction it picked up. The heartbeat went up and down a few times during the contraction. The doc was not concerned as he kept me on the monitor for 45 minutes and it did not happen again. My fluid was also checked today and it was normal, also there was no nuchal cord present. He said the cord could have been compressed due to the baby moving during the contraction or just compressed between the baby and the uterine wall. He said the rest of the NST was beautiful and had great accelerations, the other contraction had no decels, etc...and the whole picture is what you need to look at. Does this sound ok to you?
ANSWER: Hello,
Congratulations for the baby!
My first question to myself was why non-stress test at 35 weeks. It's not typical, but not unusual esp. if you have a health condition.
I am certified in advanced fetal monitoring and I would have to say to trust your doctor. He is correct than it was a beautiful NST, great accelerations and no repeats and no mention of late decelerations. If you are still worried, call your doc. They will reassure you or may offer to do another NST to ease your mind. It's always best to check back with your doctor as they know you and your baby best :)
Some of the reason parents get nervous seeing a baby's heart beat on the monitor is it doesn't "look" like the heart beat we see on a EKG machine with an adult. In simple terms, wavy, squiggly lines are normal within range. A smoother line, within range can show a resting baby or is also seen when mom has narcotics in labor.
There are different types of decelerations that can occur. A deceleration is a heartrate dip outside the normal range.
First you have to understand the reading of what is seen and interpreted: Variability, Accelerations, Baseline and Decelerations.
Variability:
The fetal heart rate in in constant flux, but within a normal range. The normal FHR range is between 120 and 160 beats per minute.
Accelerations
Accelerations are reoccurring, random increases in the Fetal heart rate( the upwards squiggles) Fetal movement, vaginal examinations, uterine contractions, umbilical vein compression, fetal scalp stimulation or even external acoustic stimulation can cause these to occur. Accelerations are considered a reassuring sign of fetal well-being. Accelerations are the basis for the nonstress test (NST). The presence of at least two accelerations, each lasting for 15 or more seconds above baseline and peaking at 15 or more bpm, in a 20-minute period is considered a reactive or good NST.
Decelerations:
Variable Decelerations
Variable decelerations are shown by an sudden fall in the fetal heart rate below baseline (like you saw) with a quick or slow dip and a variable recovery phase. Variable meaning it varies from one to the other, other babies, other decelerations.
They vary in duration, intensity and timing. They are not constantly in synch with contractions or predictable. They are also THE most commonly seen deceleration in labor. Variable decelerations are caused by compression of the umbilical cord.
The "recovery" phase of a variable decel is a positive sign and called good recovery, in other words the baby has enough energy reserve to recover from the brief pressure and is not distressed. There was a saying on Labor and Delivery "everyone's entitled to a little variable now and then". If they are occasional, no major concern, any increase, or developing pattern will be watched.
Early Decels are typically seen in transition or sometimes with babies who are low in the pelvis and are caused by head compression and the baby moves toward birth. As a nurse, they were a good sign that birth was very, very close. Like variables, they should and usually show a "good recovery" They are looked out very closely, now more by computers, to make sure they are not starting late in the contraction.
If that occurs they may be "Late decelerations"
Those are the type of decels that indicate the baby is distressed or does not have the resources or reserves to cope with labor much longer.
Late Decelerations
Late decelerations are associated with the placenta not working at 100% and it's function may be worse during contractions. Any decrease in uterine blood flow or placental dysfunction can cause late decelerations.
A late deceleration is the fall in the fetal heart rate, beginning at or after the peak of the uterine contraction and returning to baseline only after the contraction has ended and only recovering AFTER the contraction ends. Recovery can sometimes be very slow! The descent and return are gradual and smooth. It doesn't matter how low the heart rate goes, all late decelerations are considered cause for alarm.
A pattern of persistent late decelerations is called nonreassuring and if it continues and mom is not close to delivery a c/section would be performed. It's almost as if the baby is telling us, HEY, GET ME OUT NOW.
Your baby seems content by that test. Good luck to you and your family!
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QUESTION: Thank you so much for your reply! I am getting twice weekly NST's mostly because I worry a lot ;) and they are "usually" reassuring except for today's. I have also had a high risk pregnancy due to incompetent cervix/cerclage and preterm labor so they like to keep a close eye on things. I will be going to repeat my NST on Monday.
He definitely said they weren't "late" decelerations. It was just during that one contraction, there were probably 3 variable decels during it-baseline was about 125 and it dropped to about 101-105 at the worst. They were also not long at all, my doc said they had good variability, etc..and so not to worry-but of course I do! If we had started that NST just 2 mins later I would have never seen it :(
So do you agree with my doc on why they happened? I am sorry to ask so much. I have been through so much and am so worried of something happening at the end with the cord or something-knots, etc... :(
Thanks Debbie :)
AnswerHi Again,
Well, your doctor actually saw the strip, and from the description I would agree with your doctor.
Will that much follow up, your baby is being watched very very closely. I hope that can decrease your anxiety some.
About the cord, yes, occasional compression is not uncommon. This of it like this, the cord is NOT being pressed flat between two bricks or hard objects so that the blood supply is shut off.
The cord is soft and tough, the uterus around the baby is soft as well. So for instance, imagine this tough cord laying across your baby's tush, the baby pushes her tush up against your uterus. She's pushing on the cord a little, but there is nothing firm enough to cause any significant drop in blood flow. Hope that makes sense, It's hard to write a visual.
Some more cord info for you:
Up to 25 percent of babies are born with their umbilical cords wrapped one or more times around their necks. This rarely causes any problems and is called a nuchal cord.
Fetal monitoring can show heart rate deceleration during labor and delivery in babies with nuchal cords. This may reflect pressure on the cord. However, the pressure is rarely serious enough to cause death or any lasting problems, though occasionally a cesarean delivery may be needed.
And about 1 percent of babies are born with one or more knots in the umbilical cord. A knot rarely causes a problem. Any significant issues are usually seen while monitoring during labor.
Good Luck to you!
