Nomad : Parturition & Lactation

PHYSIOLOGY OF PARTURITION By Dr.M.Anthony David MD Professor of Physiology Nomad: Rep Physiol: Parturition

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WHAT IS PARTURITION? The process of expulsion of the mature fetus from the uterine cavity of the mother.  The fetus has been living in the cosy comfort of the mother’s womb.  It now has to face the harsh realities of life.  Physically speaking, it’s dependence on the mother is cut off suddenly. 

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PARTURITION 







ALSO CALLED DELIVERY, LABOR, OR CONFINEMENT USUALLY OCCURS AT THE END OF THE THIRD TRIMESTER OF PREGNANCY. IT TAKES MORE TIME AND MIGHT BE DIFFICULT FOR THE PRIMIGRAVIDA. A WOMAN DELIVERING FOR THE FIRST TIME IS CALLED A Nomad: Rep Physiol: Parturition

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PARTURITION HAS THREE STAGES:  I STAGE: 

 THE

CERVIX BEGINS TO DILATE .  From 1 cm to 10cms. 

II STAGE:  THE

FETUS IS DELIVERED, USUALLY HEAD FIRST.



III STAGE:  DELIVERY

OF THE AFTERBIRTH OR THE PLACENTA Nomad: Rep Physiol: Parturition

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POSITIVE FEEDBACK IN PARTURITION STRETCH OF THE UTERINE WALL

PG SECRETION BY THE UTERUS

UTERINE CONTRACTIONS

NEURAL AFFERENCE FROM THE CERVIX

ESTROGEN

OT RECEPTORS IN MYOMETRIUM Nomad: Rep Physiol: Parturition

OXYTOCIN SENT BY THE POST PITUITARY 5

TERM FETUS IN THE UTERUS

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STAGE I OF LABOR

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STAGE I : FETUS COMES OUT HEAD FIRST

STAGE III: PLACENTA LOOSENS & IS SLOWLY DELIVERED Nomad: Rep Physiol: Parturition

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MAJOR FACTORS CAUSING LABOUR: 

 CIRCULATING ESTROGENS: OXYTOCIN RECEPTORS   OXYTOCIN SENSITIVITY OF THE UTERINE MYOMETRIUM. 



POSITIVE FEEDBACK MECHANISMS:  OXYTOCIN:

NEURO-ENDOCRINE, POSITIVE FEEDBACK REFLEX   STRETCH LEADS TO  CONTRACTIONS Nomad: Rep Physiol: Parturition

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MINOR FACTORS CAUSING LABOUR  SPINAL

REFLEXES  VOLUNTARY ABDOMINAL MUSCLE CONTRACTIONS: “BEARING DOWN”

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TYPES OF DELIVERIES  FULL     

TERM NORMAL DELIVERY:

FTND MOST COMMON. BABY IS DELIVERED HEAD FIRST DELIVERY IS FROM THE CERVIX & VAGINA DELIVERY IS SPONTANEOUS Nomad: Rep Physiol: Parturition

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TYPES OF DELIVERIES contd. 

FORCEPS DELIVERIES: A

FORCEPS IS USED TO HELP THE FETUS TO BE DELIVERED.



CAESARIAN DELIVERY:  DELIVERY

BY OPERATION THROUGH THE ABDOMEN.  THE UTERUS IS CUT OPEN AND THE FETUS EXTRACTED.  IS DONE UNDER ANESTHESIA Nomad: Rep Physiol: Parturition

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LET’S LEARN NOW…

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PHYSIOLOGY OF LACTATION By Dr.M.Anthony David MD Professor of Physiology Nomad: Rep Physiol: Parturition

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MAMMARY GLAND: HORMONES INFLUENCING 

PRE PUBERTAL PHASE:  RUDIMENTARY



BREASTS: BREAST BUDS

PUBERTAL PHASE: HORMONES ACTING:  ESTROGENS  PROGESTERONE  CORTISOL  INSULIN  GROWTH

HORMONE  PROLACTIN

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MAMMARY GLAND: HORMONES INFLUENCING 

DURING PREGNANCY:  ESTROGENS  PROGESTERONE  CORTISOL  INSULIN  GROWTH HORMONE  PROLACTIN  PLACENTAL HORMONES: E, P &  HUMAN CHORIONIC SOMATOMAMMOTROPIN (HCS) Nomad: Rep Physiol: Parturition

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MAMMARY GLAND: HORMONES INFLUENCING DURING LACTATION:  ESTROGEN  PROGESTERONE  CORTISOL  INSULIN  GH  PROLACTIN  OXYTOCIN. Nomad: Rep Physiol: Parturition

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DEVELOPMENT OF THE MAMMARY GLAND  PRE-PREGNANT

PHASE:

DUCTS FEW

AND FAR BETWEEN ALVEOLI

 EARLY

PREGNANCY:

ALVEOLI

 MID

GROW

PREGNANCY:

ALVEOLI

ENLARGE THEY ACQUIRE LUMEN Nomad: Rep Physiol: Parturition

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DEVELOPMENT OF THE MAMMARY GLAND 

LACTATION:  ALVEOLI

DILATE  THEY ARE FILLED WITH MILK  AFTER SUCKLING, THEY LET THE MILK DOWN DUE TO THE MILK LET DOWN REFLEX. 

AFTER WEANING:  THE

GLAND REGRESSES AS A WHOLE Nomad: Rep Physiol: Parturition

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MILK SECRETION/EJECTION REFLEX SUCKLING  MILK LET DOWN

GENERAL SOMATIC AFFERENCE THROUGH SPINOTHALAMIC TRACTS

 MILK PRODUCTION PVN/ HYPOTHALAMUS RELEASE OF OXYTOCIN

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PRODUCTION OF PROLACTIN

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BREAST MILK : SYNTHESIS & SECRETION SUCKLING

STIMULATION OF NIPPLE RECEPTORS HYPOTHALAMUS

POSTERIOR PITUITARY

 DOPAMINE(PIH)

 OXYTOCIN SECRETION

 PLASMA DOPAMINE(PIH)

 PLASMA OXYTOCIN

ANTERIOR PITUITARY  PROLACTIN SECRETION  PLASMA PROLACTIN

BREASTS GLANDULAR CELLS CONTR.OF MYOEPITHELIAL Nomad: Rep Physiol: Parturition CELLS

MILK SYNTHESIS

MILK EJECTION 23

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A COMPARISON OF MILK TYPE Colustrum

8.5

3.5

FAT Gm % 2.5

Breast milk

1 to 2

6.5 - 8

3-5

0.03

4.75

3.5

0.14

Cow’s milk

PROTEIN LACTOS Gm% E Gm%

CALCIU M Gm% -

Lactalbumin

3.5  Caseinogen

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BREAST MILK IS THE BEST MILK 

BEST COMPOSITION:  CHANGES



IMMUNOGENIC:  CONVEYS



IgA (SECRETORY)

NON INFECTIVE:  NO

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WITH BABY’S AGE!

RISK OF CONTAMINATION

INEXPENSIVE Nomad: Rep Physiol: Parturition

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BREAST MILK IS THE BEST MILK BEST FOR EMOTIONAL BONDING BETWEEN THE MOTHER & CHILD.  BEST FOR THE WOMAN TO LACTATE: 

 REDUCES

INCIDENCE OF BREAST CARCINOMA  PRODUCES A BETTER FIGURE. 

NO INCONVENIENCE TO FEED AT ANYTIME. Nomad: Rep Physiol: Parturition

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APPLIED ASPECTS OF LACTATION 

CHIARI-FROMMEL SYNDROME:  GALACTORRHEA  AMENORRHEA  GENITAL

ATROPHY  PERSISTENT PROLACTIN LEVELS  NO FSH/LH  SEEN IN MOTHERS WHO DO NOT NURSE THEIR BABIES Nomad: Rep Physiol: Parturition

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APPLIED ASPECTS OF LACTATION 

GYNECOMASTIA:  DEVELOPMENT OF BREASTS IN MALES  75% NEONATES BOYS HAVE IT DUE TO MATERNAL ESTROGEN.  70% BOYS MAY HAVE SOME AT PUBERTY  CAN BE SEEN IN MEN OVER FIFTY DUE TO ANDROGEN RESISTANCE. Nomad: Rep Physiol: Parturition

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REVIEW  PARTURITION

TAKES PLACE NORMALLY AT THE END OF THE PERIOD OF PREGNANCY.  IT HAS THREE STAGES: STAGE

I : DILATATION OF THE CERVIX. STAGE II : DELIVERY OF THE FETUS/BABY. STAGE III : DELIVERY OF THE Nomad: Rep Physiol: Parturition

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REVIEW Estrogen and Progesterone primed breast tissue is acted upon by various other hormones.  Prolactin is essential for production of milk.  Oxytocin is essential for ejection of milk  There is a Positive feed back, neurohormonal reflex pathway by which milk is secreted and let down. 

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