3. Physiology
        3.8. Maternal and foetal
            3.8.2. Maternal
3.8.2.3. Endocrine changes in pregnancy

Endocrine changes in pregnancy

[Ref: PK1:p345-346; WG21:p452-p453]

Production of hormones by placenta

Peptide hormone

Human chorionic gonadotrophin (hCG)

Production

By syncytiotrophoblast cells

Structure

Made up of alpha and beta subunits
* Like pituitary glycoprotein hormones

Alpha subunit is the same as the alpha subunit of LH, FSH, and TSH

Function

Thus,

Maintains corpus luteal oestrogen and progesterone production in 1st trimester
--> Maintains pregnancy until the placenta takes over

Levels

hCG level peaks at 10-12 weeks of pregnancy then declines to term

Other notes

Detection

Secretion in other situation

 

Human placental lactogen (hPL)

aka human chorionic somatomamotropin (hCS)

Production

By syncytiotrophoblast cells

Amount produced is proportional to the size of the placenta

Structure

Very similar to human growth hormone

hPL, growth hormone and prolactin may come from a common progenitor hormone [WG21:p453]

Function

NB:

Levels

hPL level rises throughout the pregnancy and peaks near term

Steroid hormone

i.e. Oestrogen and progesterone

Placenta produces enough oestrogen and progesterone from maternal and foetal precursors to take over the function of corpus luteum after the 6th week of pregnancy

 

Other hormones produced by placenta

 

Changes in pituitary hormones

Increase in

 

Decrease in

 

Other changes

Adrenal hormones

All increase
* ???? By oestrogen and progesterone [PK1:p346]

Thyroid hormones

However,

Parathyroid hormone

Prostaglandins

Corpus luteum

 



Table of contents  | Bibliography  | Index