Fetal Malpresentation — Causes and Management

-
During early stages of normal labor, the occiput of the fetal vertex presents laterally in relation to the maternal pelvis and then anteriorly during the advanced stage of labor. Fetal malpresentation is defined as all fetal presentations, other than vertex presentation e.g. breech, face, brow, transverse lie and compound presentation. It is one of the commonest reasons for cesarean deliveries. It is important to follow obstetric principles when managing fetal malpresentations. Most of these presentations of malpresentation undergo a scheduled cesarean delivery to prevent fetal morbidity and mortality, as well as to avoid potential medicolegal issues.
Fetus and placenta
Image: “Fetus and placenta.” (Image credit: Wei Hsu and Shang-Yi Chiu) – Lessons on Life from SENP2 Sedwick C PLoS Biology Vol. 6, No. 12, e312 doi:10.1371/journal.pbio.0060312. License: CC BY 2.5

Fetal Malposition vs. Fetal Malpresentation

Fetal malposition refers to abnormal fetal vertex positions in relation to the maternal pelvis.
Fetal malpresentation refers to all fetal presentations besides the vertex (occipito-anterior) presentation.

Risk factors for fetal malpresentation

  • Multiparity
  • Multiple pregnancies
  • Prematurity
  • Uterine abnormalities like leiomyomas or uterine septa
  • Fetal anomalies like polyhydramnios
  • Placental anomalies like placenta prevue
  • Malpresentation in a previous pregnancy
  • Platypelloid and android pelvis.

Breech Presentation

In early pregnancy, the fetus is often in a breech position but, by 36 weeks of pregnancy, it assumes the vertex position, but, when this does not occur and the fetus is positioned with buttocks in the maternal pelvis, it is called a breech presentation. It is the commonest malpresentation in clinical obstetric practice and is usually diagnosed antenatally but may also be diagnosed during labor when the fetal parts are felt through the open cervical os. The incidence of breech presentation is high in cases of premature labor. Variations of breech presentation are:
  • Frank breech: in this presentation, the fetal hips are flexed, the knees are extended stretching the legs straight upwards with the head or face lying near the feet.
  • Footling breech: here, the baby’s one or both feet lie over the cervix or prolapse through the uterine cervix.
  • Complete breech: in this presentation, the fetus lies with both its hips and the knees flexed.

Diagnosis of breech presentation

Antenatally, it can be diagnosed with an ultrasound or it can even be palpated through the maternal abdominal wall by a skilled physician/midwife. Occasionally, the diagnosis of the presentation may be missed or delayed and may only be detected during labor.

Management of breech delivery

If the presentation is known beforehand, then delivery of the baby should be scheduled in a healthcare facility where surgical intervention, if indicated, can be performed. After 37 weeks of gestation when the woman is in early labor, external cephalic version can be attempted if vaginal delivery is deemed possible, if it is a single gestation, if membranes are intact, if the fetus has no growth retardation or anomalies, and there is no vaginal bleeding or history of a previous cesarean section.
Picture: Criteria for performing external cephalic version
Risks associated with external cephalic version
  • Placental abruption
  • Rupture of membranes
  • Cord prolapse
  • Fetal distress
  • Fetal hemorrhage
Vaginal delivery can proceed if external cephalic version is successful. If it is unsuccessful, then either a vaginal breech delivery should be attempted, or a cesarean delivery scheduled immediately.

Vaginal breech delivery

This can be attempted in frank or complete breech when the fetus is not too big and there is no maternal cephalopelvic disproportion. Important to remember:
  • Watch for cord prolapse
  • Meconium is not uncommon in breech deliveries
  • Ask patient to push only after confirming with vaginal examination that the cervix is fully dilated
  • In the case of fetal distress, or prolonged labor then deliver through cesarean section.

Cesarean section

Cesarean section is indicated in the presence of maternal cephalopelvic disproportion, double footling breech, breech with hyperextended head, a previous history of cesarean delivery and fetal macrosomia.
Complications of breech presentation during labor are cord prolapse with fetal asphyxia or cord compression, fetal head arrest, and fetal trauma.

Face Presentation

Here the fetal face presents with complete head extension. This type of malpresentation is associated with fewer problems during labor, especially if the head flexes during descent in the chin (mentum) anterior position.
However, in the chin/mentum posterior position, the maternal sacrum blocks the fully extended fetal head preventing descent and results in arrest of labor. This can lead to prolonged labor and cesarean section delivery. It is important not to attempt vacuum extraction in a face presentation.

Brow Presentation

In this presentation, the fetal head is partly extended and partly flexed with the mentovertical diameter presenting in relation to the maternal pelvis. It is usually diagnosed when the anterior fontanelle and supraorbital ridges are palpated during a vaginal examination in advanced labor.
Brow presentation often corrects itself during labor and therefore rarely requires a cesarean section to deliver the baby, but if the head does not flex adequately, then a cesarean section has to be performed.

Transverse Lie

In this type of fetal presentation, the fetal head lies transversely across the maternal pelvis with head on one side of the pelvis and buttocks on the other side. These cases are associated with a shoulder presentation, high incidence of cord prolapse and consequent fetal compromiseduring labor so vaginal delivery is not attempted and cesarean section recommended in all such presentations.

Compound Presentation

In this type of fetal presentation, a fetal limb presents along with another fetal part (e.g. vertex) which is closest to the dilated cervical os. Commonly, this involves a fetal arm or hand along with the vertex and rarely the breech and is encountered usually in cases after the premature rupture of membranes or in premature labor or with concomitant pelvic masses.
In these cases, it may occasionally be possible to replace the prolapsed limb. Excessive force should not be applied to the prolapsed limb as it may cause limb injury or brachial plexus injury (Klumpke’s paralysis) or Horner’s syndrome, or may displace the vertex and entrap the fetus converting it into a difficult shoulder presentation. However, in a majority of the cases, spontaneous vaginal delivery only occurs if the fetus is small or dead and cesarean section is the preferred modality of delivery.

Comentários

Enviar um comentário

Mensagens populares deste blogue

Hemorrhoids (Piles) — Symptoms and Treatment

-
Imagem
Hemorrhoids cushions are normal structures of the lower rectum.  They are very vascular and pathology develops when that vasculature becomes engorged (especially the veins). Itching and pain are common symptoms of hemorrhoid pathology. Hemorrhoids are classified on their origin relative to the dentate line: external (below the dentate line), internal (above the dentate line), and prolapsed internal hemorrhoids. Most hemorrhoids are treated with dietary modification (increase fiber) and stool softeners, but occasionally surgery is required. Table of Contents Definition of Hemorrhoids Epidemiology of Hemorrhoids Etiology of Hemorrhoids Pathology and Pathophysiology of Hemorrhoids Symptoms of Hemorrhoids Diagnosis of Hemorrhoids Differential Diagnoses of Hemorrhoids Therapy of Hemorrhoids Progression and Prognosis of Hemorrhoids Review Questions References Image : “Types of hemorrhoids” by WikipedianProlific and Mikae...
Ler mais

12 Cranial Nerves — Functions and Mnemonics

-
Imagem
Crania l nerves emerge directly via the spinal cord from the bony skull because they supply cranial structures or fulfill specific functions. During medical studies, cranial nerves are an essential element of the subjects of the brain and the nervous system. In the following, you will find a concise overview of the classification, the functions and the course of the 12 cranial nerves. Table of Contents Classification of Cranial Nerves List of Cranial Nerves Cranial nerve I: Olfactory Nerve Cranial nerve II: Optic Nerve Cranial Nerve III: Oculomotor Nerve Cranial Nerve IV: Trochlear Nerve Cranial Nerve V: Trigeminal Nerve Cranial Nerve VI: Abducent Nerve Cranial Nerve VII: Facial Nerve Cranial Nerve VIII: Vestibulocochlear Nerve Cranial Nerve IX: Glossopharyngeal Nerve Cranial Nerve X: Vagus Nerve Cranial Nerve XI: Accessory Nerve Cranial Nerve XII: Hypoglossal Nerve Overview of the 12 cranial nerves Review Questions References Image : “Cranial Nerves” by Br...
Ler mais

Nerve Tissue: Brain

-
Imagem
In LECTURIO :) - Table of Contents Introduction to the Brain The Cerebrum The Cerebellum The Meninges The Spinal Cord References Image :  “Skull and brain normal human diagram”  by Patrick J. Lynch. License:  CC BY 2.5 Introduction to the Brain The brain is the central organ of the human nervous system along with the spinal cord. It is made up of: The cerebrum Diencephalon, consisting of thalamus, hypothalamus and pituitary gland The cerebellum The brainstem- consisting of midbrain, pons and medulla Image :  “Introduction to Brain Structures”  by BruceBlaus. License:  CC BY 3.0 The organ weighs about 1400 grams on average in an adult. It is housed and protected by the skull bones which include the: Parietal Frontal Occipital Ethmoid Sphenoid bone The bones of the face Image :  “Cranial sutures shown from the top of the head”  by Xxjamesxx. License:  CC BY-SA 3.0 At birth, the paired an...
Ler mais