BIO CHEMICAL CHANGES IN PREGNANCY

Hormonal changes during pregnancy

In pregnancy placenta forms large quantities of estrogen,progestron,human chorionic gonadotropin & human somatomammotropin

These hormones are essential to normal pregnancy

HUMAN CHORIONIC GONADOTROPIN(HCG)Glycoprotein of molecular weight

39,000 HCG is secreted by syncytial

trophoblast cellsSecretion of HCG prevents

normal menstruationCan be first measured in blood 8

to 9 days after ovulationLevel of secretion reaches

maximum at about 10 to 12 weeks of pregnancy

FUNCTIONS…Same function as luteinizing

hormonePrevents involution of corpus

luteum & secrete large quantities of sex hormone

This helps the development of endometrium

Under the influence of HCG corpus luteum of mothers ovary grows twice its initial size

Effect on fetel testis:HCG exerts an …

Continuation….… Interstitial cell-stimulating

effect on testis of male fetusIt results in the secretion of

testesterone during gestation what causes the fets to grow male sex organ instead of female organ

SECRETION OF ESTROGEN BY PLACENTA

Like corpus luteum placenta secretes estrogen & progesterone

Secreted by syncytial trophoblast cells of placenta

Toward the end of pregnancy the daily production of estrogen increases

Secretion of estrogen by placenta is quite different from ovaries

Continuation..Ovaries: de novo synthesisPlacenta: formed from

androgenic steroid compounds • De hydroepiandrosterone• 16-hydroxyhydroepiandrosterone

• These weak androgens are converted into estriol,estradiol,estone.

FUNCTION OF ESTROGENFunction on most reproductive &

associated organs of motherExtreme quantities of estrogen

cause ; Enlargement of mothers uterusEnlargement of mothers breastEnlargement of female external genitalia

Relaxes pelvic ligaments of mother

SECRETION OF PROGESTERONE BY PLACENTA

Important as estrogenSecreted in moderate quantities by corpus luteum at beginning & secreted in tremendous quantities by placenta later

Increases 10 fold during the course of pregnancy

FUNCTION OF PROSTERONE

Causes decidual cells to develop in the endometrium

Decreases contractility of pregnant uterus

Help the development of conceptus

Help estrogen to prepare mothers breast for lactation

SECRETION OF HUMAN CHORIONIC SOMATOMAMMOTROPIN

Most recently discovered placental hormone

This is a protein having a molecular weight of 38000

Secreted by placenta from the fifth week of pregnancy

FUNCTION OF HUMAN CHORIONIC SOMATOMAMMOTROPIN

HCG causes at least partial development of animals breast and in some instances cause lactation

It has similar action to growth hormone

HCG causes decreased insulin sensitivity & decreased utilization of glucose

OTHER HORMONAL FACTORSo PITUITARY SECRETION

Anterior pituitary gland of mother enlarges to 50% during pregnancy, increases production of corticotropin,thyrotropin& prolactin.

Secretion of FSH & luteinizing hormone decreases due to inhibitory effect of estrogen & progesterone.

o CORTICOSTEROID SECRETION Rate of adrenal cortical secretion of

glucocorticoid increases.Vlue of aldosterone secretion reaches a peak

at end of gestation.o SECRETION BY THYROID GLAND

Thyroid gland enlarges up to 50% during pregnancy increases its production of thyroxine.

Production of thyroxine is caused by thyrotropic effect of HCG & HCT.

o SECRETION OF PARATHYROID GLANDMothers parathyroid gland enlarges during

pregnancy especially during when the mother is on ca diet

Enlargement of these glands cause calcim absorption from mothers born

Secretion of parathyroid hormone inntensifies during lactation

Growing baby need more calcim than fetus