Fetal heart monitoring in labour is the act of recording the fetal heart at regular intervals or continuously so as to identify changes in its pattern and diagnose, in a timely manner, any fetal distress that may require expediting the birth.
There are two forms of fetal monitoring in labour. The first one is intermittently utilising a Doppler that uses ultrasound technology or alternately a Pinard (a wooden, plastic or metal trumpet that works like a stethoscope). The second method is continuously monitoring the heart rate with a Cardiotocography aka CTG: a monitor with two belts that get strapped around your belly to record the fetal heart and the contractions. This trace gets printed in real time and analysed by the midwife/doctor looking after you. Women having a homebirth get offered intermittent auscultation, usually with a Doppler.
1. When did we start monitoring babies in labour?
It is hard to pinpoint to when exactly we discovered that by putting our ear on a pregnant woman’s belly we can listen the baby’s heart rate. It is likely that this method would have been used in the past to ascertain if the baby was alive during a long complicated birth. In the 19th century a Frenchman, Rene Laennec, created the little trumpet (Pinard) that we still use today, but at that time it was unlikely that women would have been subjected to a regimented schedule of heart rate auscultation as we do today. It was not until the mid 20th century with the introduction of the CTG monitor that obstetricians first attempted to uncover the normal and abnormal patterns of fetal heart in labour. Since then the only certain finding that the evidence has revealed is that CTGs use increases the rates of interventions in labour such as c-section without lowering the adverse outcomes for babies. Meaning, we are often overreacting to seemingly normal fetal heart patterns in labour. In that respect intermittent fetal heart monitoring (with a Doppler or Pinard) is as safe and effective as a CTG, most certainly for low risk women.
2. How should we use intermittent auscultation in labour?
Let’s start with NICE guidelines. This is what guides practice in every hospital in the UK and some abroad. It is where we find the best summaries of research and the most current practice, but bare in mind it takes 10 years for new research to make it into guidelines like this one.
NICE guidelines: Intermittent auscultation1.2.9Offer women with a low risk of complications, fetal heart rate monitoring with intermittent auscultation when in established first stage of labour. Do this as follows:
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1.2.10Once the woman has signs of, or is in confirmed second stage of labour:
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In summary, NICE guidelines recommend that we listen to the fetal heart every 15 minutes when you are in established labour (once you are 4cm dilated and/or having 3 regular contractions in 10 minutes). For the second stage of labour (once you are fully dilated and when you push your baby) NICE recommends that we listen every 5 minutes. This second part can go on for 2 to 3 hours. Even though this is taken like the Bible in hospitals, very few know that there is absolutely no evidence behind this common practice, and it is that, just common practice rooted on culture and expert recommendations. As an alternative, the 2018 WHO recommendations for intrapartum care suggest fetal heart auscultation every 15 to 30 minutes in established labour and every 5 minutes in second stage. They also have suggested research questions at the end of their document and one of them is determining the effect on birth outcomes from the current intermittent auscultation protocols. We simply do not know if 15 minutes is better than 20 minutes or 30 minutes, but there seems to be a more widespread concern over the heart rate during the pushing stage. I have also seen other protocols in studies from developing countries where the fetal heart rate is auscultated every 30 minutes in first stage, every 15 minutes in the passive phase of second stage (fully dilated but not pushing) and every 5 minutes during the pushing stage.
There is also no clinical basis to start fetal monitoring right at the beginning of established labour, it is a consensus. Physiologically there is no increased risk for babies once you reach 4cm. As a matter of fact other countries recommend that we change the established labour definition to 6cm. Think that some women get to the hospital fully dilated with no monitoring at home and no-one gets scolded for arriving “late”, they are praised for having done it all at home! Regular fetal movements and liquor colour is a good indication of how baby is coping with labour too.
The truth for homebirths is that we rarely do vaginal examinations so regularly as to know exactly at what point the woman is at. We start listening to babies every 15 minutes when the contractions are regular 3 in 10 minutes and we move to second stage auscultations when there are signs of full dilatation such as involuntarily pushing, anal dilatation, woman opening her bowels, etc.
3. How does intermittent auscultation detect fetal distress?
NICE guidelines also recommend that, during intermittent auscultation, we listen to the heart rate straight after the contraction and for one minute. This is important. The reason behind this is that, when babies are distressed, their heart rate drops during the contraction, and we know it takes a minute or more to recover after the contraction. Therefore, it is crucial that we listen straight after the contraction and not randomly every 15 minutes. When we hear a drop in babies heart rate we call this a deceleration. The ones we are concerned about are the late ones, so the ones we hear after the contraction has finished. Babies’ heart rate can drop for various reasons including cord compression or cord around the neck (which is not necessarily an issue by the way) but if baby is coping well with labour, that normal drop in the heart rate recovers within that contraction and we do not hear it while performing intermittent auscultation. Good randomised controlled studies show that intermittent auscultation is as good as CTG monitoring for low risk mums and even for some high risk cases! (excludes induction of labour).
There tend to be more changes (decelerations) in the fetal heart rate pattern in second stage, specially during the pushing stage, hence the increase frequency in monitoring. Again, these are generally normal and indicative that the baby is coping with labour as long as they are not late decelerations.
It should be noted that labour is a hypoxic event. Meaning that every time you have a contraction there is less oxygen getting to baby as the placenta get squished. The baby automatically drops their heart rate to cope. Babies also have more red blood cells in circulation to carry more oxygen as their oxygen saturation in uterus is around 85% in pregnancy (adults is 95-100%). There are other things we look out for when listening to the baby’s heart rate. We make sure the rate is between 110 and 160 beats per minute, that there is good variability between one beat to another and that there are accelerations present.
4. What happens if there are concerns with the fetal heart rate at a homebirth?
If we hear decelerations in labour, baby has a raised heart rate or a reduced variability, the first thing we will ask ourselves is what is causing it. We will do a full set of observations on you and suggest you change position. The usual culprits tend to be infection (which would show as a raised temperature and raised heart rate for you) or cord compression (such as the baby leaning on the cord and reducing the blood flow, hence why a change of position to lying on your left lateral would help). There are also other possibilities such as cord prolapse, placental abruption, etc. but these are rarer and have other serious signs and symptoms. The other check we would offer is a vaginal examination as you may be fully dilated which would explain the odd deceleration.
If we hear decelerations we would do the above and then listen after the next 3 contractions. If we still have concerns we would recommend transfer to the hospital for a CTG to figure out how well baby is coping. Even though CTGs increase the rate of interventions they give us a better picture of how the baby is doing and we could anticipate how much time we have before baby is in serious trouble. So it can help the obstetricians decide: should we carry on as we are, do we need a CS now or can we wait and use a forceps if baby is distressed at the end? The guidelines even recommend discontinuing the CTG if baby’s heart rate seems well after a 30 mint trace. It is important to bear in mind that babies will usually give us signs that they are not coping well and it is better for your baby to be born somewhere where there is a team of specialists (obstetricians, paediatricians, extra midwives) to support her/him in her/his transition. However, if the baby is born in a poor condition unexpectedly we are fully equipped to support him/her.
There are two common scenarios where we may hear decelerations in labour. One is in the first stage of labour (before you start pushing) and the other when the baby is low in the birth canal and he/she is minutes from being born. In the first scenario, transfer is likely the best recommendation as there are still hours to go and more chances of baby getting distressed (we may not know why). There may be other concerning clinical signs such as a long labour or meconium in the waters. In the second scenario baby is either about to be born (and likely in good condition but we are prepared if not) or a change in position usually helps. I have seen this countless times, decelerations appear when the mother is pushing on her back and they get resolved when she goes on all fours. In my experience supporting low risk women in labour it has been rare to have to transfer to an obstetric unit for fetal heart concerns without other warning signs happening before hand.
5. What is better for fetal monitoring in labour: a Doppler or a Pinard/fetoscope?
NICE guidelines recommend that we use either a Doppler or a Fetoscope, but personally I feel that those guidelines were not made for fetoscopes. They were made to try and mimic a CTG trace, which requires frequent auscultations.
A Doppler is nice and easy. You can hear the baby’s heart rate which some women find reassuring and the volume can be adjusted for those that want a quiet room. It does not, however, record the real heart rate but an amplification of the same. It sounds electronic. One of the benefits is that we do not always need to be very accurate in where we position it on your belly as it can find the heart rate from far as long as you direct it well. There is a small chance that we could be picking up your maternal pulse instead, specially if your pulse is high. This is why we would always palpate your pulse every hour to make sure we have the right heart rate. Another benefit of the Doppler is that it is waterproof so it can go in the pool. (Please, do not auscultate your baby’s fetal heart rate by yourself as in the picture. If you have concerns please reach out to your midwife or the hospital).
A fetoscope is like a stethoscope with a trumpet at the end. It is a fancy Pinard. It is made of plastic and metal. A Pinard can be made of wood, plastic or metal. A fetoscope/pinard allows us to listen to the real heart rate of the baby but it takes some getting used to and a quieter room/mother. It is described as hearing a clock ticking under a pillow. It is also great to figure out the baby’s position (such as breech or head down) because it needs to be very close to the baby’s heart rate to pick it up. This presents some difficulties in labour as it can make the process of finding the heart rate a bit lengthy. Bear in mind that babies rotate, descend and change position in labour. Another draw back is that it will pick up too many background noises if submerged in the pool, making it impossible to use in water. Plus the lead is very short! This will involve you standing up in the pool every time an auscultation is due. If you intend to deliver your baby in the pool chances are that we will not be able to monitor his/her heart rate at the critical pushing stages, as you will probably not want to move every 5 minutes!
Most of us midwives have been trained to use a Pinard but the reality is that we have only used it in practice a few times. I have decided to offer all my clients regular auscultations of the fetal heart rate with a fetoscope/pinard antenatally so I do not loose such a valuable skill. My preferred instrument is the Doopler for labour as it is the less invasive, but I understand some women may be concerned over ultrasound waves exposure to their babies. If that is the case, I can try a fetoscope in labour with a plan of what to do if it becomes a difficult undertaken.
I cannot proficiently comment on the risks of ultrasound waves with Dopplers but think that your baby will be exposed to a total of 40 minutes of ultrasound waves on a lengthy 10h first stage of labour and another 25 minutes on a 2h second stage of labour. This is similar to the exposure time of having the two routine scans in pregnancy. The reality, though, is that homebirths are quicker and we are not there monitoring your baby’s heart rate from the moment you are 4cm, neither will we necessarily know you are fully dilated exactly when you are.
As far as research is concerned the Cochrane library have a summary of studies comparing outcomes between Doppler and Pinard and most concluded that a Doppler detects more fetal heart abnormalities than Pinards do. Most studies did not have enough numbers to determine whether this translated in a reduction in poor neonatal outcomes, but they did find more cesarean sections in the Doppler group. Note that these studies have been done in developing countries with higher neonatal mortality rates and where the default instrument is the Pinard, hence midwives are proficient in their use. The Doppler is the new instrument in these studies and the midwives were not so familiar with them, which could have led to overdiagnosis of fetal heart abnormalities. The auscultation protocols also varied from country to country. Interestingly, as per studies that look at the experiences of midwives using Pinards, many reported not liking the Dopplers when they were introduced. Experienced Pinard users in a Norway study report using other ways of assessing fetal wellbeing by listening to the timber and strengh of the fetal heart rate. An art lost in contemporary midwifery practice in the west!
6. What if you decline some or all fetal auscultations?
If you decline all fetal auscultations in labour I am happy to still support you as an independent midwife at your homebirth providing that you are well informed of the risks of not having auscultation and that we have a back up plan if we spot any risks that would benefit from some auscultation. It is true that most babies cope well with straight forward labours and it is true that as midwives we can perform manoeuvrers to resuscitate a baby that is born in poor condition (such as inflating the lungs, inserting a device to open the airway, inspecting the airway, suctioning any obstruction, ventilate the lungs and even start chest compressions). But we prefer to use our skills and knowledge to avoid having a baby born in poor condition in the first place. This involves spotting complications during labour, acting on them and/or transferring to the appropriate facility if needed where more help is available. This is what intermittent fetal heart monitoring in a homebirth does, it is a warning sign. I am yet to attend a low risk birth where an abnormal fetal heart rate pattern on intermittent auscultation during the first stage of labour results in a false alarm. CTGs do cause false alarms, intermittent auscultation not so much. As a matter of fact, no studies have been performed that have compared a group of women receiving fetal monitoring and one that does not, so we truly do not know if regularly listening in (as opposed as just if there are concerns) improves fetal outcomes.
It is common for women to decline the odd auscultation if they happen to be so immersed in labour that they don’t want to move. I will never force it. I would only strongly advise that we listen if there are concerns, like a deceleration. You would have heard it too! Sometimes women decline that one time when we are having trouble finding the heart rate because the baby is so low, contractions are back to back and the baby is about to be born.
This observation is based on my personal experience, but I also did it myself, once, in my labour when my baby was crowning and all my focus was inward. Moving to facilitate the midwives auscultation was not convenient and I could feel baby move inside of me. I would understand if you do!
As a middle ground, we can always come up with a personalised plan of how often or with what instrument you want me to listen in. It can look like using the fetoscope in established labour and switching to the Doppler in second stage or if I cannot easily find the fetal heart with the fetoscope. The frequency of auscultation can also be decided by you and can be increased if there are concerns or risk factors making you “high risk”. Of course I will always recommend that we follow the official NICE guidelines, particularly around fetal monitoring, but I will never pressure or scare you into compliance. This is the beauty of being your independent midwife. I trust that you know what you are doing and you trust that I know what I am doing.
7. What to bear in mind about intermittent auscultation in labour?
To have it, not to have it, how often to have it and with what instrument? It is all your choice but this is a practice that is very ingrained in our midwifery culture and one that gets scrutinised heavily in litigation cases when there is a poor outcome with a baby. It is also a very good way to tell how baby is coping with labour.
A very small percentage of women completely decline it because they trust their body and their instinct to know if something is wrong. Some find it extremely reassuring to hear the baby’s heart rate in labour, others don’t like the Doppler’s noise in labour. There are also those that decline a Doppler in favour of a fetoscope out of concern over the risks of ultrasound waves on baby.
I like to see fetal monitoring like a dance, a choreography. I usually move around you to accommodate for whatever position you are in. I bend down into the pool, I get between your legs if you are on all fours, I get on my hands and knees to find the baby’s heart if you are on the floor. It is definitely not necessary to have to ask you verbally every time we approach you to listen in. There is an understanding. You may sign to us that that is not a good time to listen, that the contraction actually has not finished and we wait.
All in all, this is my experience and knowledge of auscultating the fetal heart rate with a Doppler. If you wish to have an independent midwife that is open to other forms and patterns of fetal heart monitoring in labour why not book a free online chat with me?
Hello! My name is Irene Vine and I am an independent midwife covering Suffolk, Essex, Cambridge and East London. I provide full antenatal, postnatal and birth care including homebirths and outside of guidelines care. I am passionate about supporting women achieve a birth experience where they feel empowered, heard and understood. If you would like to experience the best possible care with unrushed appointments and a midwife who is always at the other end of the phone, give me a call!