As the third trimester progresses, it seems that there is so much focus and anticipation on a baby becoming engaged, so firstly, lets understand what being ‘engaged’ really means.
When your baby descends into your pelvis, how far it has descended is measured by the ‘station’, with 0 station being engaged. When a baby is at 0 station, it’s head is resting at what is called the ischial spines (sometimes just referred to as ‘spines’) which is the narrowest part of your pelvis. If your baby is above the spines, he or she is not engaged and is measured as a minus number, for example if your baby was 5cms above spines, you would be -5, or if baby was 1cm above the spines, -1. Once your baby descends past 0 station, it’s given a positive number, so if baby is 1cm below spines, it’s +1 and so on.
When Should A Baby Be Engaged?
This is completely up to your baby. Yes, first time babies can engage sooner than second or subsequent, but this does not mean that if your baby doesn’t engage before labour starts, that there is a problem. Even for first time mothers, babies can engage during labour, with the early contractions helping to bring baby down lower into your pelvis. So there is no formula at all to work this out, just when your baby is ready. It’s nothing to do with your body’s ability to birth or your baby being cheeky! Your baby knows when it’s the right time and will engage when he’s good and ready – so trust your body and trust your baby that they will work in unison when the time is right.
Remember: your body is designed to go into labour – mother nature has it worked out really well, I think we’d be in trouble as a species if our babies didn’t engage and our bodies didn’t go into labour eventually!
If My Baby Isn’t Engaged, Does It Mean It’s Too Big For My Pelvis?
Not at all. In the small number of cases where the baby doesn’t engage even at 41-42 weeks, it’s more likely that your baby has adopted a tricky position in your pelvis rather than the baby being too big for your pelvis, remembering that it simply still may be that your baby just isn’t ready to engage. For those babies who do get in a posterior or other tricky position, the spinning babies website is brilliant for helping malpositioned, posterior or breech babies, and you can also also seek alternative therapies like chiropractic and acupuncture to help with position. The spinning babies site is a great resource regardless, as it helps your baby get into the best position for birth, which is called ‘optimal fetal positioning’.
Also, there are two great articles on BellyBelly you must read if you are concerned about your baby’s size or your pelvis size:
What About Inductions?
Inducing a high baby can be disastrous – not only do inductions already increase the risk of fetal distress and caesareans, but if the waters are broken with a high/unengaged baby, cord prolapse is a big risk, as the cord could drop below the baby’s head (as the head isn’t near the cervix to block it) and the cord can prolapse through the vagina. A full term pregnancy is up to 42 weeks, so given your baby is healthy and you are healthy, there is no reason to schedule an induction at least until then, to give your baby the best chance at being born on the day she or he decides is the perfect time. Baby is putting on finishing touches to cope with the world on the outside, especially in relation to breathing, so every day in your womb counts.
To give you an idea of how inductions can affect the outcome of babies who are not ready, a baby induced at -5 station will give you a 70-80% risk of a caesarean section. So inductions are best avoided, and trust and waiting is the best medicine.
Will I Need A Caesarean?
There is a very low chance you will need one if you just wait and see – you are more likely to have one if you are induced. There will be a very small number of women who have a baby in a position too tricky to be born vaginally, but this can happen if your baby is engaged or not. Not being engaged does not mean this will happen to you specifically! If you are worried about position, see Spinning Babies as per above and keep active in your pregnancy and the birth. Walking for 30 minutes a day is great for your mood as well as your body and baby, as is swimming (breaststroke or anything else belly down!). Walking the stairs is an awesome pre or during labour tool, as it helps moves to move your pelvis around for your baby. Don’t push yourself too much though!
Many women who have babies that engage at the time of labour go on to have healthy vaginal births.
Why the Fuss?
Unfortunately, it’s been stated in obstetric textbooks that the majority of first babies should engage several weeks before labour.
Ironically, research contradicts this and suggests that approximately 70-75% of babies may not be engaged at the start labour. The research also looks at the rate of caesareans where the baby is not engaged prior to labour, and found that approximately 85-90% of babies that were not engaged at the onset of active labour were born vaginally. Hardly anything worth worrying about! Considering we know the caesarean rate in Australia is amongst the highest in the world, well above the World Health Organisation’s recommendations, I think we need to spend more time ‘waiting and seeing’ and intervening when really needed. Unengaged babies are not distressed, they are quite happy waiting in there (unless of course there is something else going on) so why fix something that’s not broken – and potentially cause more problems it in the process? There is no point risking major surgery which carries its own set of risks – unless the benefits outweigh the risks.
Research On Unengaged Babies and Labour
Incidence and significance of the unengaged fetal head in nulliparas in early labor
Int J Biol Res Pregnancy. 1982;3(1):8-9, Takahashi K, Suzuki K.
“Our clinical experience contradicts the traditional view that in the great majority of nulliparas with cephalic presentation the fetal head is engaged 1-2 weeks prior to onset of labor. In 75.4% of the 175 cases fetal head was not engaged in early labor. No significant statistical difference between the unengaged-head group and the engaged-head group was determined for incidence of vaginal delivery, cesarean section for cephalopelvic disproportion, midforceps delivery, mean and low Apgar scores, and birth weight. Thus, absence of engagement is not always indicative of pelvic contraction.”
Labor and delivery in nulliparous women who present with an unengaged fetal head.
Department of Obstetrics and Gynecology, Albert Einstein College of Medicine, New York, NY, USA.
J Perinatol. 1998 Mar-Apr;18(2):122-5, Murphy K, Shah L, Cohen WR
OBJECTIVE: We assessed the relation of fetal station in early labor to subsequent patterns of dilation and descent and to the probability of cesarean delivery.
RESULTS: Of the 132 participants, 29 (22%) presented with an engaged fetal head, and 103 (78%) presented with an unengaged fetal head. In the unengaged group, 15 (11%) presented with a floating fetal head (-3 station or above), and 88 (67%) presented with a dipping fetal head (-2 or -1 station). A floating head in latent-phase labor conferred a longer second stage (p = 0.02), a trend to more active-phase labor disorders (p = 0.06), and a greater risk of cesarean delivery. Overall, 12 patients (9%) underwent primary cesarean section: 2 (6.9%) from the engaged group, 6 (6.8%) from the dipping group, and 4 (27%) from the floating group (p = 0.042).
CONCLUSION: Most nulliparous women in this study presented in labor with an unengaged fetal head. Those with a floating fetal head demonstrated higher rates of cesarean section than those with dipping or engaged heads in early labor. [Overall 90.3% delivered vaginally.]”