Hormonal roles in each trimester related to pregnancy symptoms

1. By
Bavani S
M.Sc Advanced
biochemistry

2. Endocrine changes during
pregnancy
 During pregnancy, various endocrine changes occurs in
the body.
 Anterior pituitary enlarges upto 36% due to increase in
lactotroph size and number.
 Number of somatotroph and gonadotroph decreases.
 Posterior pituitary diminishes in size.
 Gonadotropin produced by pituitary decreases – due to
increase in estrogen.
 ACTH increases and drops 50% before delivery. Because
both placenta and pituitary gland act as its source.
 Arginine vasopressin increases since it rapidly destructed
by vasopressinase produced by trophoblast.

3. THYROID GLAND
Thyroid gland increases by average of
18% and also increase in TBG (thyroid
binding globulin.
This happens due to the thyrotropic
effect of hCG
 Induction of hepatic synthesis of TBG
by estrogen.

4. ADRENAL GLAND
 Increase in ACTH increases the cortisol secretion.
 Due to hyperestrogenemia, renin increased which
inturn increases angiotensin-II which inturn lead
to
8-10 fold increase in aldosterone production.
 But it does not show any effects because of
increased production

5. Pregnancy hormones
 Follicular stimulating hormone
 Luetinizing hormone
 Human choronic gonadotropin
 Progesterone and estrogen
 Relaxin
 Oxytocin
 Prolactin

6. Follicular stimulating hormone
 FSH is the hormone secreted by pituitary gland which
involve in follicular development.
 It aids in development of placenta during pregnancy.
 It is maintained in low level throughout the pregnancy
in order to prevent the follicular development.
 But very low level indicates hypopituitarism or turner’s
syndrome

7. Luetinizing hormone
 LH is the hormone which stimulates ovaries to
produce estrogen and also causes ovaries to release egg
during ovulation.
 During pregnancy, it stimulate the corpus luetum to
produce progesterone.

8. hCG – HUMAN CHORIONIC
GONADOTROPIN
 It is the special hormone produced only during
pregnancy.
 hCG produced by placenta immediately after the
implantation of fertilized egg.
 Pregnancy tests are done by detecting it in the urine.
FUNCTION
 Maintain corpus luteum in the early pregnancy.
 It repel the immune cells of the mother since it is
highly negative charge.
 Plays role in cellular differentiation and proliferation.

9. Progesterone
 Progesterone is produced by corpus luetum during
early pregnancy later it is produced by placenta.
 Also called as pregnancy hormone.
 It thickens the endometrium wall of uterus and also
prevent contraction of myometrium.
 Stimulates the growth of blood vessels, plays vital role
in implantation of egg, growth of foetus and prevent
lactation and also strengthens the pelvic wall muscles
in preparation of labour.

10. ESTROGEN
 As like progesterone, estrogen also produced by corpus
luetum in early stages and later produced by placenta.
 Helps in uterus growth and maintains its lining and
supports foetal development including organ
deveopment.

11. RELAXIN
 Relaxin levels are highest during the first trimester of
pregnancy.
 Prevent premature birth by prohibiting contraction of
the uterine muscles.
 It relaxes blood vessels, increase the blood flow to the
placenta and kidneys.
 It aids in delivery, by relaxing the joints in the pelvis
and widens the cervix.

12. OXYTOCIN
 Also called as LOVE HORMONE.
 Oxytocin produced by pituitary at the end of
pregnancy.
 During labour, it triggers contraction.
 Oxytocin stimulates powerful contraction that help to
thin and open the cervix, move the baby down and out
of the birth canal, push out the placenta.
 It also aids in release of milk during breast feeding.

13. PROLACTIN
Prolactin produced by anterior
pituitary especially by lactotrophs.
It plays massive role in lactation.
It promote milk production in mother
in response to the suckling of young
after birth.

14. Hormone levels throughout the
pregnancy.

16. Hormonal effects in each trimester
1st trimester
 Progesterone and estrogen increases dramatically.
 Special hormone Human chorionic gonadotropin
begins to produce.
 Progesterone prepares your uterus lining for the egg to
implant and it acts as a muscle relaxant, and also
prevents uterus contraction.

17. Progesterone – classic irritant
Estrogen promotes increase in blood flow.
Frequent urination.
hCG – pregnancy hormone, reason for
nausea, morning sickness.
2nd trimester
Relaxin – hormone helps to relax the smooth
muscles in the pelvis, cervix and uterus and
also promote the growth of placenta.
Experience of backpain and soreness in hip
and pelvis.

18. Increase in estrogen and progesteron stimulate
the melanocyte stimulating hormone.
It triggers melanocyte cells to produce melanin,
which gives skin colour.
It is known as mask of pregnancy.
3rd trimester
Swelling around ankles and feet.
Progesterone relax the sphincter at the base of
esophagus, causes acid reflux or heart burn.
Prolactin prepares the breast tissue for
lactation

19. Parturition
Oxytocin increases and drop in progesterone level.
Oxytocin produces body contraction to eliminate
placenta.
Oxytocin and estrogen help to release prostagladins,
which soften the cervix to prepare for birth, relaxin
ramps up to loosen the ligaments and further soften
and open the cervix.
Postpartum
Endorphins increase after birth. It helps to manage
pain , makes them to feel like superhuman.