Labour and Delivery - Hyperexcision

Last updated: November 19, 2024

Table Of Contents

Overview
Fetal Orientation
Maternal changes
Stages of labor
Cardinal movements of delivery
Prevent Infections during Delivery

Overview

Labor is a physiological sequence of regular painful uterine contractions that results in progressive effacement and dilation of the cervix and voluntary bearing-down efforts leading to delivery (expulsion per vagina of the products of conception). Cervical dilation w/o uterine contraction = cervical insufficiency. Uterine contractions w/o cervical changes = false labour (Braxton Hick’s contractions; disappears with IM opioids)

Objectives of intrapartum care
- Improve outcome of labor and delivery
- Prevent, predict, diagnose, and appropriately manage fetal hypoxia and acidosis
- Assist the mother to enjoy the experience of childbirth and avoid unnecessary delay, pain, or trauma and prevent dehydration and infection
Treatment of the parturient
- Admit when the cervix is dilated to 3cm or there is ROM)
- Orders
  - IV access
  - Clear liquid diet (in case of emergency C/S)
  - Notify anaesthesia (ready for a spinal block or emergency C/S)
  - Continuous Feral Monitoring and Partograph(to check for fetal distress)
  - Encourage Left lateral decubitus position (relieve pressure on the IVC)
- Begin pushing (bearing down, at full dilation in coordination w/contractions)
- Administer IV oxytocin (immediately after delivery to reduce the risk of uterine atony and haemorrhage)
- Monitor for at least two hours after delivery

Fetal Orientation

Fetal Lie

Fetal lie is the relation between the fetal and maternal vertical axis. Women with an unstable fetal lie (fluctuating at term) should be routinely admitted as there is a risk of cord prolapse when the membrane ruptures.

Lie	Description
Longitudinal lie	Fetal and maternal vertical axes are parallel
Transverse lie	The fetal and maternal vertical axes are perpendicular. Often presents with the shoulders
Oblique lie	Fetal and maternal vertical axes are diagonal

Fetal presentation

Fetal presentation is the part of the fetus that is engaging at the pelvis. An external cephalic version can convert a breech to a cephalic presentation about half the time.

Presentation	Description
Cephalic presentation	Head first. A hard, globular, independently ballotable mass in the presenting area.
Face presentation	Face presents first
Breech presentation	Buttocks/Sacrum with or without the legs present first. A broad, soft, irregular, non-ballotable bulky mass in the presenting area
Complete breech	Breech with the thighs and legs flexed
Frank breech	Breech with the thighs flexed and legs extended (feet in face)
Footling breech	Breech with the thighs and legs extended. Can be single or double footling.
Shoulder presentation	Shoulder presents first, commonly in transverse lie
Compound presentation	More than one presenting part e.g. shoulder + head

Fetal position

The fetal position is the position of the presenting part relative to the maternal pelvis. The presenting part may be occiput (cephalic), mentum (facial), or sacrum (breech). To determine the position, feel for the posterior fontanelle (three-sided, back of the head)

The convention goes (side) + (presenting part) + ant/post/trans

Occiput anterior (OA)
- Occiput is directed anteriorly
Left occiput anterior (LOA)
- Occiput is directed anteriorly, but slanted towards the maternal left
Left occiput tranverse (LOT)
- The occiput is directed towards the maternal left
Right occiput transverse (ROT)
- The occiput is directed towards the maternal right

Fetal attitude

This is the degree of flexion/extension of the fetal head in cephalic presentation

Vertex attitude (ideal)
- Maximal flexion
Military attitude (forehead attitude)
- Some flexion (anterior fontanelle presents first)
Brow attitude
- Some extension
Facial attitude
- Maximal extension
- Mentum anterior: chin faces the symphisis
- Mentum posterior: chin faces the coccyx

Synclitism

Synclitism is the relation between the pelvic inlet plane and the occipito-frontal plane (line from temple to temple).

Normal Synclitism
- Parallel pelvic inlet plane and occipito-frontal plane
Asynclitism
- The sagitta suture is in the transverse diameter of the pelvic inlet (not between the symphysis pubis and sacral promontory)
Anterior asynclitism (Naegele obliquity)
- Sagittal suture tilts towards the sacral promontory. Anterior parietal bone presents first.
Posterior asynclitism (Litzmann obliquity)
- Sagittal suture tilts towards the symphisis pubis. Posterior parietal bone presents first

Fetal station

Fetal station is the descent of the fetal presenting part relative to the maternal ischial spine, expressed in cm above (minus) or below (plus).

Maternal changes

Cervical dilation

Cervical dilation is important in defining what stage of labor the mother is in. 10cm dilation is consistent with the beginning of the seconds stage of labor.

Fingers	Dilation
1 finger	2cm
2 finger	3.5cm
3 fingers	5.5 cm
4 fingers	7.5 cm

Cervical effacement

Effacement is essential for delivery. It is the shortening (thinning) of the cervix. Mediated by prostaglandins and oxytonin. Happens early on in labour (latent Phase I). Should be 100% by active labor, just below delivery. Cervica ripening agents can be used to move effacement along (e.g. Oxytocin, Misoprostol, Laminaria, Dinoprostone)

Feature	Percent effacement
2cm	0% effacement
1cm	50% effacement
Thin membrane	100% effacement

Stages of labor

Labor is regular contractions (every 5 mins lasting approximately 30 seconds), accompanied by cervical change

Braxton hicks contractions
- Regular contractions without cervical change

	Primipara	Multipara
Latent stage one	< 20 hours	< 14 hours
Active stage one	< 5-6 hours	<4-5 hours
Rate of cervical dilation	1 – 1.2 cm/hr	1/2 – 1.5 cm/hr
Stage two	< 2 hours	< 1 hour
Stage three	30 min	30 min

***If the mother has received spinal anaesthesia add 1 hour to stage 2 labor

Stage one

Closed to full dilation (10cm). Fetal assessment is done via Leopolds maneouver, fetal monitoring, and vaginal exam. Fetah HR is charted q30min on the partogram. Buscopan (Hyoscine) shortens the first stage of labor by accelerating cervical dilatation

Latent stage one: Closed to 4 cm dilated (very slow progress of dilation, effacement is going on)
Active stage one: 4 cm to full dilation (fully effaced, dilation accelerates). Fetal head is engaged and cardinal movements begin to occur
Fetal monitoring
- Fetal HR q30min charted on partogram
- Transitory changes on cardiotocometry (Decelerations)
  - Early deceleration
  - Late deceleration
  - Variable deceleration
Maternal monitoring
- Pulse, Temp, and BP q1-2h
- Uterine contractions q30min
- Cervical dilation and station q4h
- Meconium staining noted (Sx of fetal decompensation) – first, second, and third degree
Sedation/Analgesia
- Analgesia (Morphine, Tramadol)
- Antiemetics e/g/ IM Phenergan 25mg
- Endonox (Nitrous oxide) inhalation
- Epidural anesthesia (’Painless labor) – hypotension, vaccum deliveries, C/S

Stage two

Full dilation to delivery of the fetus.

Sensation of bearing down/gaping of the anal opening and vulva/distension of the perineum

Stage three

Delivery of the fetus to delivery of the placenta

Stage Four

Two hours following delivery.

Cardinal movements of delivery

These are important changes in the position and attitude of the fetus as it passess through the birth canal. The ischial spine narrows the transverse diameter as the fetus moves towards the mid-pelvis. We need the baby’s head to rotate from and OT position to OA position during descent. The cardinal movements allows this by making the maximal diameter of the fetal head (occipitofrontal diameter) correspond with the maximal diameter of the maternal pelvis.

Cardinal Movement	Description
Engagement	Widest part of the presenting part has successfully passed through the pelvic inlet (OT). Clinically identified when ≤ 3/5 of the fetal head is palpable above the symphisis pubis
Descent	Fetal head descends in the pelvis (OT)
Flexion	Fetal head flexes to allow smalled diameter to present (OT)
Internal rotation	Fetal head rotates from a transverse position to a more AP position (OT → OA)
Extension	Fetal head exteds to facilitate delivery of the head
Restitution (External rotation)	The head immediately aligns with the fetal shoulders after delivery through the vulva (Body rotates such that the head is in a transverse position and the shoulders – biacromial diameter – are along the AP maternal axis, facilitating delivery of the shoulders.
Expulsion	Posterior shoulder is delivered. Fetal body is delivered.

Prevent Infections during Delivery

Reference Intervals ›

Biochemistry

ACTH	P: <80 ng/L
ALT	P: 5–35 U/L
Albumin	P: 35–50 g/L
Aldosterone	P: 100–500 pmol/L
Alk. phosphatase	P: 30–130 U/L
α-Amylase	P: 0–180 IU/dL
α-Fetoprotein	S: <10 kU/L
Angiotensin II	P: 5–35 pmol/L
ADH	P: 0.9–4.6 pmol/L
AST	P: 5–35 U/L
Bicarbonate	P: 24–30 mmol/L
Bilirubin	P: 3–17 μmol/L
BNP	P: <50 ng/L
CRP	P: <10 mg/L
Calcitonin	P: <0.1 mcg/L
Calcium (ionized)	P: 1.0–1.25 mmol/L
Calcium (total)	P: 2.12–2.60 mmol/L
Chloride	P: 95–105 mmol/L
Cholesterol	P: <5.0 mmol/L
VLDL	P: 0.128–0.645 mmol/L
LDL	P: <2.0 mmol/L
HDL	P: 0.9–1.93 mmol/L
Cortisol AM	P: 450–700 nmol/L
Cortisol Midnight	P: 80–280 nmol/L
CK ♂	P: 25–195 U/L
CK ♀	P: 25–170 U/L
Creatinine	P: 70–100 μmol/L
Ferritin	P: 12–200 mcg/L
Folate	S: 2.1 mcg/L
FSH	P: 2–8 U/L ♂; >25 menopause
GGT ♂	P: 11–51 U/L
GGT ♀	P: 7–33 U/L
Glucose (fasting)	P: 3.5–5.5 mmol/L
Growth hormone	P: <20 mu/L
HbA1C (DCCT)	B: 4–6%
HbA1C (IFCC)	B: 20–42 mmol/mol
Iron ♂	S: 14–31 μmol/L
Iron ♀	S: 11–30 μmol/L
Lactate (venous)	P: 0.6–2.4 mmol/L
Lactate (arterial)	P: 0.6–1.8 mmol/L
LDH	P: 70–250 U/L
LH	P: 3–16 U/L
Magnesium	P: 0.75–1.05 mmol/L
Osmolality	P: 278–305 mosmol/kg
PTH	P: 0.8–8.5 pmol/L
Potassium	P: 3.5–5.3 mmol/L
Prolactin ♂	P: <450 U/L
Prolactin ♀	P: <600 U/L
PSA	P: 0–4 mcg/mL
Protein (total)	P: 60–80 g/L
Red cell folate	B: 0.36–1.44 μmol/L
Renin (erect)	P: 2.8–4.5 pmol/mL/h
Renin (recumbent)	P: 1.1–2.7 pmol/mL/h
Sodium	P: 135–145 mmol/L
TBG	P: 7–17 mg/L
TSH	P: 0.5–4.2 mU/L
T4	P: 70–140 nmol/L
Free T4	P: 9–22 pmol/L
TIBC	S: 54–75 μmol/L
Triglycerides	P: 0.50–2.3 mmol/L
T3	P: 1.2–3.0 nmol/L
Troponin T	P: <0.1 mcg/L
Urate ♂	P: 210–480 μmol/L
Urate ♀	P: 150–390 μmol/L
Urea	P: 2.5–6.7 mmol/L
Vitamin B12	S: 0.13–0.68 nmol/L
Vitamin D	S: 50 nmol/L

Arterial Blood Gases

pH	7.35–7.45
PaCO₂	4.7–6.0 kPa
PaO₂	>10.6 kPa
Base excess	±2 mmol/L

Urine

Cortisol (free)	<280 nmol/24h
Hydroxyindole acetic acid	16–73 μmol/24h
Hydroxymethylmandelic acid	16–48 μmol/24h
Metanephrines	0.03–0.69 μmol/mmol cr.
Osmolality	350–1000 mosmol/kg
17-Oxogenic steroids ♂	28–30 μmol/24h
17-Oxogenic steroids ♀	21–66 μmol/24h
17-Oxosteroids ♂	17–76 μmol/24h
17-Oxosteroids ♀	14–59 μmol/24h
Phosphate (inorganic)	15–50 mmol/24h
Potassium	14–120 mmol/24h
Protein	<150 mg/24h
Protein/creatinine ratio	<3 mg/mmol
Sodium	100–250 mmol/24h

Haematology

WCC	4.0–11.0 ×10⁹/L
RBC ♂	4.5–6.5 ×10¹²/L
RBC ♀	3.9–5.6 ×10¹²/L
Hb ♂	130–180 g/L
Hb ♀	115–160 g/L
PCV ♂	0.4–0.54 L/L
PCV ♀	0.37–0.47 L/L
MCV	76–96 fL
MCH	27–32 pg
MCHC	300–360 g/L
RDW	11.6–14.6%
Neutrophils	2.0–7.5 ×10⁹/L (40–75%)
Lymphocytes	1.0–4.5 ×10⁹/L (20–45%)
Eosinophils	0.04–0.44 ×10⁹/L (1–6%)
Basophils	0–0.10 ×10⁹/L (0–1%)
Monocytes	0.2–0.8 ×10⁹/L (2–10%)
Platelets	150–400 ×10⁹/L
Reticulocytes	0.8–2.0% / 25–100 ×10⁹/L
Prothrombin time	10–14 s
APTT	35–45 s

Paediatric

Pulse Rate (bpm)
Neonate	140–160
Infant <1yr	120–140
1–5 years	110–130
5–12 years	80–120
>12 years	70–100
Respiratory Rate (tachypnoea)
0–2 months	≥60/min
2–12 months	≥50/min
1–5 years	≥40/min
>5 years	≥30/min
Blood Pressure (mmHg)
Term	65/45
1 year	75/50
4 years	85/60
8 years	95/65
10 years	100/70
Weight Formulas
3–12 months	(a + 9)/2 kg
1–6 years	2a + 8 kg
>6 years	(7a − 5)/2 kg
Haemoglobin (g/dL)
Term newborn	13–20
1 month	11–18
2 months	10–15
1–2 years	10–13
>2 years	11–14
MUAC (6 months–5 years)
Obese	>17.5 cm
Normal	13.5–17.4 cm
At risk	12.5–13.4 cm
Moderate malnutrition	11.5–12.4 cm
Severe malnutrition	<11.5 cm
Developmental Milestones
Social smile	1.5 months
Head control	4 months
Sits unsupported	7 months
Crawls	10 months
Stands unsupported	10–12 months
Walks	12–13 months
Talks	18 months
CSF WBC (/mm³)
Term newborn	0–25
>2 weeks	0–5

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