What is a Cephalic Presentation: What is its Success Rate for a Normal Delivery
Pregnancy is an amazing phenomenon that even-though everyone knows the biology behind it, never ceases to surprise you at every corner. Despite a perfectly normal pregnancy, no one can exactly predict how you are going to deliver until the moment comes and speaks for itself. Your baby in the womb is like a tiny astronaut floating in space tethered to his spacecraft, except that his space is filled with amniotic fluid, his tether supplies him oxygen and nutrition and you are the spacecraft! Now that you could visualize the scene clearly you can clearly imagine the various positions your baby can assume to his/ her whim and fancy. We are here to understand what it means for a baby to be in cephalic presentation and how it helps in a normal vaginal delivery. To know that we need to know about Quickening first.
The baby begins to move freely inside the mother’s uterus as early as 14 weeks but she begins to perceive those movements for the first time only at around 20 weeks. It is a paradox that it is being called “Quickening” although there is a delay in picking up those painless kicks since its inception. Some mothers even find it difficult to describe their first baby movements and quite often you can hear them describe them as twinges, flutters, bubbles, or even butterflies!
3. Position & Presentation Of Baby:
Until about 34 weeks your baby doesn’t assume one particular position due to the freedom of movement given by its tiny size to swim across the sea of amniotic fluid. Between 34 to 36 weeks when the baby is grown enough to occupy most of the womb it settles down to one final position which is commonly referred to as “Presentation”. When your baby is preparing for birth, the term “presentation” is often used to describe how it is oriented. It could be head down, bottom down, foot down, or various other intermediates each having its own share of benefits or risks in and around delivery.
4. Cephalic Presentation & Types:
Cephalic presentation is the position when your baby is positioned head-down and bottom-up inside the uterus. The majority of newborns (96%) are born in this manner (1). Nature makes every effort to achieve this position since it is the most favorable for normal vaginal birth. After 36 weeks of pregnancy, a spontaneous transition from breech to cephalic is improbable (2)
Cephalic Presentation Can Be Divided into Two Categories
- When the baby is head-down and facing the mother’s back, it is called the Occipito-anterior position because the back of the baby’s head, called the occiput, lies beneath the mother’s tummy.
- When the baby is head-down facing the mother’s tummy with its occiput lying close to the mother’s back we call it Occipito-posterior presentation. Some love to call it a “Sunny-side up” baby! This presentation can make vaginal delivery a bit harder since the head is relatively wider in this position. There is a good chance that the baby’s head could get stuck on its way down during delivery or can become a nightmare for the mother since it usually causes prolonged labor. Though the mother needs to bear a lot of pain the baby also receives its fair chunk of perinatal complications.
Occasionally in cephalic presentation, the baby’s head may get tilted back during the descent making the face or the eyebrows the presenting part instead of the occiput. Such malpresentation has potential risks and may or may not end with a vaginal delivery(2). Those are very rare and usually seen with preterm deliveries.
5. How To Know If Your Baby Is Cephalic Without Scan:
There’s something to the mother’s instinct that we cannot decipher with modern technologies. Though there are never-ending debates on the safety of scans during pregnancy a mother can easily know if her baby is lying head-down or feet-down. She can feel those soccer kicks well at her upper stomach or just under her ribs when the baby is in Cephalic presentation.
6. How The Doctor Finds It Clinically:
When you are in the good hands of a well-experienced doctor he/she can tell you the position of your baby just by physically examining you. Palpating your abdomen for the fetal head, back and limbs can say a lot about the position of the baby. Sometimes a supplementary vaginal examination helps to affirm the presentation.
7. Role Of Ultrasound Scan:
An ultrasound scan towards the end of the third trimester can give enough and more information on the position of the baby, adequacy of liquor inside the uterus, placental status, etc. A regular ultrasound screening at 35 + 0 to 36 + 6 weeks gestation can help to alleviate the problem of unanticipated non-cephalic presentation in childbirth. (4).
8. Listening To The Baby’s Heartbeat:
A fetal heartbeat can be heard either manually by a simple stethoscope or by pressing a small Doppler transducer device against your abdomen which picks up and augments the baby’s heartbeat from deep inside your uterus. In Cephalic presentation when the baby is in the ideal occipital-anterior position, the baby’s back will come to lie just beneath the mother’s abdomen. This can be confirmed by the louder and clearer heartbeat because fetal heart sounds are best heard through the fetal back.
In a cephalic presentation when you near your delivery time the baby drops into the mother’s pelvis which happens usually between 37 to 40 weeks. This process is “Lightening”. The mother suddenly feels more room to breathe freely since the baby has dropped down and her lungs are freer to expand better now.
But wait!! Just when you want to breathe out a sigh of relief you are now called to the washroom more than usual. Yes! you need to take frequent leaks after lightening because now your bladder has less space to expand and hold in urine and the baby’s head is a constant irritant to the bladder asking you to void often.
10. Success Rate For Normal Delivery In Cephalic Presentation:
Nearly 96% of vaginally delivered babies are in cephalic presentation. There is a huge success rate of normal delivery; in this presentation because during delivery the baby’s head is the largest, and the most challenging part to come out because it stretches the birth canal to its maximum potential. When the baby’s head is out, the remainder of the torso comes out without difficulty.
11. Can You Do Anything To Get Your Baby To Cephalic Presentations?
Regular walking, mild to moderate exercises, and leaning forwards while sitting on a chair instead of laying back may help in aligning the baby in an ideal cephalic presentation optimum for normal vaginal delivery.
12. Final Thoughts:
Cephalic presentation is one of the many ways a baby can present itself during delivery. Though it is the highly preferable position for successful vaginal delivery; it doesn’t mean all other positions need medical intervention. Today’s advancing medical knowledge accompanied by our ancestral wisdom guides the mother’s instinct in choosing what is right for her baby. Many times mother’s instincts have disproven calculated predictions. When you trust your body under the light of knowledge on pregnancy; and childbirth your choices will not let you down. Never hesitate to speak to your health care provider to clarify those gnawing doubts that keep you awake at night to have a memorable delivery.
Glezerman M. Planned vaginal breech delivery: current status and the need to reconsider. Expert Rev Obstet Gynecol. 2012;7(2):159-166. doi:10.1586/eog.12.2
Makajeva J, Ashraf M. Delivery, Face And Brow Presentation. 2022 Jan 14. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 33620804.
De Castro H, Ciobanu A, Formuso C, Akolekar R, Nicolaides KH. Value of routine ultrasound examination at 35-37 weeks’ gestation in the diagnosis of non-cephalic presentation. Ultrasound Obstet Gynecol. 2020 Feb;55(2):248-256. DOI: 10.1002/uog.21902. PMID: 31671470.
Dr. Anand Mariaselvam, MBBS, CBE(CAPPA)
Govt. Medical Officer (India)