Parturition

Parturition

What is Labour (Human Parturition)?

Labour is the physiological process that results in:

• birth of a baby.
• delivery of the placenta.
• and the signal for lactation to begin.

How to Diagnose Labour?

Symptoms of Labour

1. Labour-like pain:

   • Regular uterine contractions which increase in:
     • Frequency
     • Strength
   • Sufficient uterine contractions are defined as:
     • a. Frequency 4-5 contractions /10 minutes
     • b. Each contraction lasting 45 seconds to 60 seconds

2. Show:

   • Bloody stained mucus (a blood-stained plug of mucus passed from the cervix).

3. Spontaneous rupture of membranes (SROM):

   • Feel like a gush of warm fluid trickle from the vagina.
   • It will usually be clear and odourless.
   • Differential Diagnosis (DD):
     1. Urine:
        • incontinence.
        • UTI (Urinary Tract Infection).
        • vesicovaginal fistula.
     2. Excessive vaginal discharge:
        • Physiological.
        • Pathological.

False Labour Pain

• Braxton Hicks contractions.
• Features of Braxton Hicks contraction:
  • Infrequent, irregular uterine contractions.

True vs. False Labour Pain

True labour pain	False labour pain
Regular	Irregular
Increase in frequency, duration & intensity	Do not
Pain felt in the abdomen & radiated to the back	Pain felt mainly in the abdomen
Progressive dilation of cervix	Not affect the cervix
Contractions persist whether mother is active or resting	Contractions stops by resting, walking or changing position
Cannot be relived by antispasmodics and sedatives	Can be relived by antispasmodics and sedatives
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How to Confirm Amniotic Fluid (Liquor)?

• Nitrazine test.
• Fern test.
• Fibronectin (Fetal fibronectin works as a glue to hold the amniotic sac to the uterine lining).
• Alpha-fetoprotein blood tests.
• Amnisure test (Placental alpha microglobulin-1 (PAMG-1)).

Theories of Onset of Labour

The onset of labour involves:

• changes in hormonal levels of estrogen and progesterone.

• increased production of prostaglandins.

• elevation of levels of corticotropin-releasing hormone.

• increased sensitivity of the myometrium to endogenous oxytocin.

• Prostaglandins: involved in cervical ripening and uterine contractions.

• Progesterone: decreases in late gestation.

• Estrogen: promotes uterine contraction and cervical dilation.

• Corticotropin-releasing hormone: increases prostaglandin activity on myometrium.

Initiation of Labour Diagram

Understanding Labour: The 3 Ps

An understanding of the physiological and anatomical principles involved in normal labour is best summarized using the ‘3 Ps’: powers, the passages, and the passenger.

1. The powers:
   • Contractions of the uterus.
   • The maternal effort of pushing in the second stage of labour.
2. The passages: the birth canal.
3. The passenger: the fetus.

Outcomes of the 3 Ps

• When the 3Ps are favourable ➡️ Normal labour (normal vaginal delivery).
• When any of the 3Ps are unfavourable ➡️ Abnormal labour, leading to a need for intervention & increased risk of morbidity or mortality.