Puerperium and Lactation-By:Dr.DHIREN BHOI

8/14/2019 Puerperium and Lactation-By:Dr.DHIREN BHOI

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Puerperium and LactationPuerperium and Lactation

Dr. DHIREN B. BHOI

M.V.Sc., (Gynaecology)

E. Mail:[email protected]


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PuerperiumPuerperium The period after parturition when

reproductive tract repairs itself and returns toits non-pregnant condition (Uterineinvolution)

Become prepared for another pregnancy

Begins immediately after parturition andrecovery period varies among species

Short and smooth recovery period isdesirable


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Events of PuerperiumEvents of Puerperium

1. Myometrium contraction and expulsion of

lochia

2. Endometrial repair

4. cyclcity:

6. Elimination of bacterial contamination


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Stage 1:Myometrium contraction and expulsion of lochia


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Stage 2 & 3:Stage 2 & 3: Endometrial repairEndometrial repairResumption of ovarian function

Necrosis of caruncular tissues

Sloughing of the caruncular tissues

Reorganization of uterine

endometruim

First postpartum ovulation


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Continuation of uterine contraction

Rise in Estradiol and increase in leukocytes

High degree of

Stage 4:Stage 4:Elimination of bacterial contamination


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LactationLactation


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The Mammary GlandThe Mammary Gland

Exocrine gland; common to all mammals

Function: nourish the neonate

-Food source: fat, protein, sugar (CHO),

vitamins, minerals, water

-Protection: immunoglobulins


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Loosely considered part of the reproductive system:

Serves a reproductive function; nourishment of

the neonate = survival of species.

Relies on same endocrine (hormonal) support for

development and function.

Example: gonadal steroids, prolactin, etc.



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Embryo Origin:

The mammary gland is a skin gland



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Secretory Tissues:

Glandular; secreting tissue =

Alveoli:

Duct system; lined by epithelial cells

Lobules & lobes; clusters of alveolar tissue

supported by connective tissue



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Milk SynthesisMilk Synthesis

Milk synthesis is dependent on: no. secreting cells

supply of milk precursor

milking frequency

No. secreting cells is dependent on:

genetics endocrine support for mammogenesis


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Example:

What volume of blood would a 1400 lb. Holstein

pump per day?

Blood Flow

(cattle)

Blood ComponentsBlood Components

1400 lb. Cow ~ .9 liters/ heart stroke

Volume/day = .9 x 70 strokes/min = 63 liters/min

63 liters/min x 1440 min/day = 90,720 liters/day

= ~ 22,600 gal/day


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Blood Flow (cattle)

Volume of blood/ volume of milk synthesized =(this is an approximation; actual ratio is

affected by stage of lactation, efficiency, etc.)

Blood ComponentsBlood Components


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Steroid Hormones and MammogenesisSteroid Hormones and Mammogenesis

Estrogens:

follicle, placenta,

Progesterone:

corpus luteum, placenta,

Corticoids:

adrenal cortex


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Estrogens (E2) (follicle, placenta)

1)

2)

3) synergize with progesterone & prolactin tostimulate protein synthesis and duct growth



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Progesterone (P4) (corpus luteum, placenta)

1)stimulates lobulo-alveolar growth retards milksynthesis

2)retards synthesis of enzymes (a-lactalbumin)

necessary for lactogenesis in the prepartummammary gland



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Lactogenesis; CortisolLactogenesis; Cortisol

Action of cortisol:( from adrenal cortex)

(dexamethasone is synthetic cort.)

1) synthesis stimulated by maternal, fetal ACTH

essential to lactogenesis (adrenalectomy

> nolactogenesis)

2)

M iM i


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Placental E2 + luteal P4 =

duct development

lobulo-alveolar development

suppression of milk synthesis

(P4 suppresses

-lactalbumin; lactose synthesis

MammogenesisMammogenesis

(Mammary Growth and Development)(Mammary Growth and Development)

M iMammogenesis


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Action of cortisol + PRL:

increase PRL receptor synthesis

increase protein transcription/translation

cortisol is permissive to action of PRL

MammogenesisMammogenesis

(Mammary Growth and Development)(Mammary Growth and Development)


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LactogenesisLactogenesis

(Milk Synthesis)(Milk Synthesis)

How does P4 retard milk synthesis in thenonlactating mammary gland?

Blocks glucocorticoid (cortisol) receptors

Cortisol + PRL stimulates synthesis of PRLreceptors on mammary cells

P4blocks induction of PRL receptors

Retards synthesis of a-lactalbumin, casein mRNA

Retards casein, a-alactalbumin, lactose synthesisthus, retards milk synthesis


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Endocrine Glands SupportingEndocrine Glands Supporting

Mammary FunctionMammary Function

GH (STH, BST):

increases milk yield

Action:

increases gluconeogenesis

increases blood glucose

increases efficiency of

production (greater lbs. of

milk/ lb. DMI)

E d i Gl d S tiE d i Gl d S ti


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Endocrine Glands SupportingEndocrine Glands Supporting

Mammary FunctionMammary Function

Pancreas (islets of Langerhans; protein hormones)

(responsive to blood glucose concentration)

Glucagon (alpha cells):

increases lipolysis

increases glycogenolysis

depresses cellular glucose uptake

catabolic to adipose, muscle, liver tissue


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Lactogenesis = initiation ofmilk synthesis

initiated in the E2/P4

primed mammary

gland when:

corpus luteum regresses

P4 declines

cortisol increases

PRL, GH increase

these circumstances occur

at parturition

Lactogenesis


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Puerperium and Lactation-By:Dr.DHIREN BHOI