birth (parturition) process

• Prior to labour 

  Several hormonal changes 

  • Cause ligaments of pelvis to soften - more pliable for birth 
  • Increase response of uterus to stimuli
  • Strengthen contraction of uterus muscles 

  Cervix softened, shortened in length, begun to open a little 
• Prior to labour

  Foetus :  

  • settled head in pelvis 
  • facing right or left hip bone
  • knees drawn up to its abdomen with legs crossed - take up as little room as possible
  • one side of head pressed against mother’s bladder, other against bowel
• During final three months of gestation, uterus undergoes weak, irregular contraction 

  • Gradually become stronger and more frequent during last weeks 
  • Eventually become strong and occur about every 30 minutes
• First stage of labour 

  Time from onset of labour to complete dilation of cervix 

  Average of 8 to 9 hours (first child), 4 hours (subsequent children) 
• First stage of labour 

  Waves of contraction travel from upper part of uterus towards cervix 

  • Similar to peristalsis 
  • Muscle fibres making up uterus shorten a small amount, pulling on cervix

  Pull on cervix shortens it so it no longer projects down into vagina 

  At same time, cervix is opened - allows foetus to move more deeply into pelvis 
• First stage of labour

  As contractions are more frequent and stronger, head is pushed more forcefully against cervix 

  Cervix is fully dilated, uterus + cervix + vagina form birth canal 
• Second stage of labour 

  Delivery of foetus 

  From full dilation of cervix to birth 

  20mins to 2hrs
• Second stage of labour

  Begins with bursting of membrane surrounding foetus + gush of fluid from vagina 

  • May occur much earlier or not until foetus is ready to be born 
• Second stage of labour

  As foetus moves through cervix, its head stretches the vagina

  • Stimulates the women to contract abdominal muscles 

  + Contraction of uterus pushes foetus through vagina 

  • Babies head turns to face towards mother back 

  Each contraction, baby’s head advances a small amount 

  Retreats a little between contractions 
• Second stage of labour

  Eventually head stretches vaginal entrance and tissue between entrance and anus 

  Tissue becomes tightly stretches over foetus’s head 

  Once head emerges, foetus turns sideways - allow shoulder and rest of body move easily through birth canal
• Pressure on head passing through birth canal may push it out of shape

  Bones of skull are pliable - joints allow some degree of overlap 

  Head down allows, 

  • Head to act as wedge to force open cervix and vagina 
  • Foetus to begin breathing before completely free from birth canal
• Third stage of labour 

  Uterus continues to contract, five minutes after delivery placenta + other membranes + remains of umbilical cord are expelled (afterbirth)
• Third stage of labour

  Umbilical cord is clamped in two places and cut 

  Arteries and vein contract before or immediately after cut 

  Stum of cord dries up and galls away after a few days - navel remains