Chapter 3 Physiology in pregnancy
? pregnancy,the condition of being with child or
gravid,is the process of embryo and fetus growing
and developing in the uterus,From the fertilization
to the expelling of the fetus with placenta and
membranes.
? Sec.1 fertilization,development,transport and
implantation of fertilized ovum.
? Sec.2 the formation and function of fetal attachment.
? Sec.3 the maternal changes during pregnancy.
Sec.1 fertilization,development,transport and
implantation of fertilized ovum
? 1.fertilization:semen enters vagina →
spermatozoons contact with endometrium,the
α-/β-amylase remove the decapacitation factor
on spermatozoons’ acrosomal enzyme,then the
spermatozoons with the ability of fertilization
(capacitation) in uterus and fallopian tubes,the
spermatozoons meet the ovum at the ampulla →
acrosome rupture → acrosomal enzyme
released (acrosome reaction) → the
spermatozoons penetrate the radiate corona and
zone pellucida → Fusion
? 2.implantation,fertilized ovum→vitelline sphere
(early blastosphere) →into uterine cavity→late
blastosphere→implantation including
apposition,adhesion,penetration.
? The necessary factors:
? (1)the zone pellucida disappear.
? (2)the syncytiotrophoblastic cells appear.
? (3)synchronic development of blastosphere and
endometrium.
? (4)enough progesterone.
? 3.decidua formation,thicker,more vascular and
edematous than premenstrual endometrium.
implantation
Decidua change
True basal
capsular
Embryo and fetus characteristics
? 1,Embryo,the first 8 weeks from
pregnancy
? 2,Fetus,after 9 weeks from pregnancy
? Fetal length,<20 weeks M2
? >20 weeks M X 5
Fetus physiological
characteristics
? 1 Circulatory system
– (1) anatomy,1 umbilical vein; 2 umbilical
arteries; ductus arteriosus; foramen ovale;
ductus venosus
– (2) circulatory characteristics
Fetus physiological
characteristics
2,Fetal blood
hemopoiesis,3 weeks after fertilization,
york sac,liver and bone marrow
fetal blood volume,125mL/kg of the
fetus at term
Fetus physiological
characteristics
3,Fetal respiratory system
the timetable of lung maturation and
identification of biochemical indices of
functional fetal lung maturity are important to
the obstetrician.
a sufficient amount of surface-active
materials in the amniotic fluid is evidence of
fetal lung maturity.
Surfactant,produced by type II cells of the
lung alveoli; active component is a specific
lecithin or dipalmitoylphosphatidylcholine,
Fetus physiological
caracteristics
4,Gastrointestinal tract
swallowing begins at 10-12 weeks,16
weeks,gastrointestinal function is
established,
5,Liver,Hepatic enzyme is lack during
fetal period,a very limite capacity for
converting free bilirubin to conjugating
bilirubin
Fetus physiological
caracteristics
? Urinary system
– The fetal kidneys start producing urine at
12 weeks’ gestation,7-14mL/day by 18
weeks,27mL/hr or 650 mL/day at term.
? Genital system
– Genital organ is developed from 9 weeks of
pregnancy (male); 11-12 weeks (female).
Placenta
? 1,Organization of placenta
? Amniotic membrane
? Chorion frondosum
? Basal decidua
– Size and weight of placenta
? Weight,450 – 650g
? Diameter,16-20cm
? Thickness,1-3cm
Placenta
? Function of placenta
? Transfer oxygen and nutrients from the mother
to the fetus and conversely the transfer of
carbon dioxide and other metabolic wastes
from fetus to mother
? Method of transfer,simple diffusion; facilitate
diffusion; active transport
Function of placenta
? 1,gas exchange
? 2,Transfer nutrient
? 3,Remove fetal catabolism
? 4,Defense function
? 5,Synthesize function,HCG,HPL,
Estrogen,pregensterone,oxytocinase,
HSAP( heat stable alkaline phosphatase)
Fetal membrane,umbilical
cord and amniotic fluid
? Fetal membrane,chorion and amnion
? Umbilical cord,extends from the fetal
umbilicus to the fetal surface of the placenta,
length,30-100cm (55cm) diameter,0.8-
2.0cm
? Amniotic fluid,50mL at 12 weeks; 400mL at
midpregnancy; 1000mL at term.
– Resource of amniotic fluid,an ultrafiltrate of
maternal plasma in early pregnancy; fetal urine
after 20 weeks
Function of amnionic fluid
? 1,Serve to cushion the fetus,allowing
musculoskeletal development and
protecting it from trauma.
? 2,Maintains temperature and has a
minimal nutritive function
? 3,Promote the normal growth and
development of the lungs and
gastrointestinal tract.
? Sec.3 changes during pregnancy
? (一 )changes of reproductive tract.
? 1.uterus
? (1)corpus,a increase in size (7*5*3 →
35*22*25cm),the capacity (10→5000ml),the
weight (70→1100g),the thickness (1→2.0-
2.5cm→ 0.5-1cm); the rate of the hypertrophy
of different parts varies (fundus→inferior
portion→cervix) so that the contractility
decreases from fundus to cervix,the fetus is
delivered.
? Hypertrophy of the uterine muscular cell
? with the pregnant weeks,more vascular(450-650ml/min)
? (2)isthmus:softer and longer(1→7-10cm),lower segment
? (3)cervix,increased vascularity,edema of the entire cervix,
hyperplasia of cervical glands.
? 2.ovary,enlarged,ovulation and new follicle is stopped.
luteum produces E and P from 7 weeks of pregnancy; but
start to atrophy after 10 weeks of pregnancy,the fuction is
replaced by placenta.
? 3.fallopian tubes, is prolonged but not hypertrophy
? 4.vagina,violet coloration;desquamation of epithelium with
more glycogen↑→acidity↑.
? 5.vulva:pigmentation.
Uterine contraction
? Braxton Hicks contraction- contraction
without pain
– Rare,irregular,and asymmetric
– Intrauterine pressure,5-25mmHg,duration
< 30s
? (二 )breasts
? An increase in size and a nodular sensation due to the
hypertrophy of the mammary alveoli,the nipples soon
become larger,more deeply pigmented and more
erectile.scattered around the areola are some roundish
nodules called Montgomery tubercles which result from the
hypertrophy of the sebaceous glands.
? 三,circulatory system
? 1.heart:the growing uterus pushes the diaphragm
upward,with the result that the heart is displaced to the
left,upward and somewhat in the direction of the anterior
chest wall.a certain degree of rotation is believed to take
place.the capacity increases by 10%,the heart rate
increases by 10-15bpm.
? 2.output:increases from 10weeks,the peak at 32-34w.
? 3.Bp.:few changes if any,
? 4.venous pressure:increased vp,in the legs is
demonstrable in later months of pregnancy,which
contributes to the ankle edema,varicose veins in the legs
and vulva during gestation.
? Supine hypotension syndrom,supine position for a long
time → inferior vene cava compressed → back-
volume↓→ output↓→Bp↓→ cm,of hypotension.
? (四 )blood system
? 1.volume:increasing from 6-8w,peak at 32-34w,about
1500ml (1000ml of plasma,500ml of erythrocytes →
hemodilution)
? 2.composition,RBC→3.6*1012/L,Hemoglobin→110g/L,
WBC → 10*109-12*109/L,coagulating factors → most
inceasing → hyper-coagulation,plasmal protein
decreases mildly due to hemodilution.
? (五 ) urinary system
? both RPF,and GFR.increase by about 35% and 50%
respectively,the metabolites of the gravida /fetus can be
excreted.under the influence of progesterone,a condition of
atonia in relaxation or loss of irritability not only of
uterus,but also of the ureters,large bowel and bile
ducts→dilatation of ureters and renal pelvis associated with
stasis of urine → acute nephropyelitis especially in the right
side.
? (六 ) respiratory system:in a word,the ventilation volume
increases;the immunologic competence↓.
? (七 ) digestive sys:estrogen→gingiva-hyperplasia
progesterone→atonia of stomach and bowel→ heart
burn,vomit,constipation
? (八 )skin
? 1.the pigmentation of the areola,linea alba,vulva,occasionally
irregularly shaped,brownish patches of varying size appear on
the face and neck,the cloasma or the mask of pregnancy,which
fortunately usually disappears after delivery.
? 2.during late months of pregnancy,reddish,slightly depressed
streaks often develop in the skin of abdomen,and sometimes
also in the skin covering the breasts and the thighs.these striae
gravidarum occur in about 1/2 of all pregnancies.
? (九 )endocrine changes
? 1.pituitary gland:the anterior lobe hyperplasia
? (1)high level of E and P→inhibites Gn releasing
? (2)PRL:increases from 7w,peak ante-delivery
? 2.adrenalin cortex:the level cortisol and aldosterone increases
by 3 and 4 times respectively
Striea gravidarum
? 3.thyroid gland,the enlargement usually concomitant with
normal pregnancy due to hypertrophy of adenomatous tissue,to
an increase blood supply and to the formation of new
follicles.but most thyroxin is connected with thyroxin binding
globulin,so no hyperthyroidism occurs.
? (十 )metabolic changes
? 1.BMR:mildly rising,
? 2.weight,from 13w increases by 350g per week,about 12.5Kg
during the entire pregnancy.
? 3.metabolism of carbohydrate
? (1)fasting-sugar lower due to higher insulin-secretion
? (2)insulin-resistant factors
? 4.fat metabolism
? Deposit of fat increasing charaterized by a
hyperlipemia and a tendency to ketosis.
? 5.protein metabolism:positive nitrogen balance
? 6.water metabolism:water-retention of about 7L
? 7.mineral metabolism:in the late months of
gestation→
? calcium and iron supplying→to avoid deficiency of
calcium and iron.
? (十一 )bone,joint and ligament
? 1.bone:no changes normally.
? 2.joint and ligament:relaxin→loosening of joints and
ligaments→the birth canal widened.
thanks
Hegar
? pregnancy,the condition of being with child or
gravid,is the process of embryo and fetus growing
and developing in the uterus,From the fertilization
to the expelling of the fetus with placenta and
membranes.
? Sec.1 fertilization,development,transport and
implantation of fertilized ovum.
? Sec.2 the formation and function of fetal attachment.
? Sec.3 the maternal changes during pregnancy.
Sec.1 fertilization,development,transport and
implantation of fertilized ovum
? 1.fertilization:semen enters vagina →
spermatozoons contact with endometrium,the
α-/β-amylase remove the decapacitation factor
on spermatozoons’ acrosomal enzyme,then the
spermatozoons with the ability of fertilization
(capacitation) in uterus and fallopian tubes,the
spermatozoons meet the ovum at the ampulla →
acrosome rupture → acrosomal enzyme
released (acrosome reaction) → the
spermatozoons penetrate the radiate corona and
zone pellucida → Fusion
? 2.implantation,fertilized ovum→vitelline sphere
(early blastosphere) →into uterine cavity→late
blastosphere→implantation including
apposition,adhesion,penetration.
? The necessary factors:
? (1)the zone pellucida disappear.
? (2)the syncytiotrophoblastic cells appear.
? (3)synchronic development of blastosphere and
endometrium.
? (4)enough progesterone.
? 3.decidua formation,thicker,more vascular and
edematous than premenstrual endometrium.
implantation
Decidua change
True basal
capsular
Embryo and fetus characteristics
? 1,Embryo,the first 8 weeks from
pregnancy
? 2,Fetus,after 9 weeks from pregnancy
? Fetal length,<20 weeks M2
? >20 weeks M X 5
Fetus physiological
characteristics
? 1 Circulatory system
– (1) anatomy,1 umbilical vein; 2 umbilical
arteries; ductus arteriosus; foramen ovale;
ductus venosus
– (2) circulatory characteristics
Fetus physiological
characteristics
2,Fetal blood
hemopoiesis,3 weeks after fertilization,
york sac,liver and bone marrow
fetal blood volume,125mL/kg of the
fetus at term
Fetus physiological
characteristics
3,Fetal respiratory system
the timetable of lung maturation and
identification of biochemical indices of
functional fetal lung maturity are important to
the obstetrician.
a sufficient amount of surface-active
materials in the amniotic fluid is evidence of
fetal lung maturity.
Surfactant,produced by type II cells of the
lung alveoli; active component is a specific
lecithin or dipalmitoylphosphatidylcholine,
Fetus physiological
caracteristics
4,Gastrointestinal tract
swallowing begins at 10-12 weeks,16
weeks,gastrointestinal function is
established,
5,Liver,Hepatic enzyme is lack during
fetal period,a very limite capacity for
converting free bilirubin to conjugating
bilirubin
Fetus physiological
caracteristics
? Urinary system
– The fetal kidneys start producing urine at
12 weeks’ gestation,7-14mL/day by 18
weeks,27mL/hr or 650 mL/day at term.
? Genital system
– Genital organ is developed from 9 weeks of
pregnancy (male); 11-12 weeks (female).
Placenta
? 1,Organization of placenta
? Amniotic membrane
? Chorion frondosum
? Basal decidua
– Size and weight of placenta
? Weight,450 – 650g
? Diameter,16-20cm
? Thickness,1-3cm
Placenta
? Function of placenta
? Transfer oxygen and nutrients from the mother
to the fetus and conversely the transfer of
carbon dioxide and other metabolic wastes
from fetus to mother
? Method of transfer,simple diffusion; facilitate
diffusion; active transport
Function of placenta
? 1,gas exchange
? 2,Transfer nutrient
? 3,Remove fetal catabolism
? 4,Defense function
? 5,Synthesize function,HCG,HPL,
Estrogen,pregensterone,oxytocinase,
HSAP( heat stable alkaline phosphatase)
Fetal membrane,umbilical
cord and amniotic fluid
? Fetal membrane,chorion and amnion
? Umbilical cord,extends from the fetal
umbilicus to the fetal surface of the placenta,
length,30-100cm (55cm) diameter,0.8-
2.0cm
? Amniotic fluid,50mL at 12 weeks; 400mL at
midpregnancy; 1000mL at term.
– Resource of amniotic fluid,an ultrafiltrate of
maternal plasma in early pregnancy; fetal urine
after 20 weeks
Function of amnionic fluid
? 1,Serve to cushion the fetus,allowing
musculoskeletal development and
protecting it from trauma.
? 2,Maintains temperature and has a
minimal nutritive function
? 3,Promote the normal growth and
development of the lungs and
gastrointestinal tract.
? Sec.3 changes during pregnancy
? (一 )changes of reproductive tract.
? 1.uterus
? (1)corpus,a increase in size (7*5*3 →
35*22*25cm),the capacity (10→5000ml),the
weight (70→1100g),the thickness (1→2.0-
2.5cm→ 0.5-1cm); the rate of the hypertrophy
of different parts varies (fundus→inferior
portion→cervix) so that the contractility
decreases from fundus to cervix,the fetus is
delivered.
? Hypertrophy of the uterine muscular cell
? with the pregnant weeks,more vascular(450-650ml/min)
? (2)isthmus:softer and longer(1→7-10cm),lower segment
? (3)cervix,increased vascularity,edema of the entire cervix,
hyperplasia of cervical glands.
? 2.ovary,enlarged,ovulation and new follicle is stopped.
luteum produces E and P from 7 weeks of pregnancy; but
start to atrophy after 10 weeks of pregnancy,the fuction is
replaced by placenta.
? 3.fallopian tubes, is prolonged but not hypertrophy
? 4.vagina,violet coloration;desquamation of epithelium with
more glycogen↑→acidity↑.
? 5.vulva:pigmentation.
Uterine contraction
? Braxton Hicks contraction- contraction
without pain
– Rare,irregular,and asymmetric
– Intrauterine pressure,5-25mmHg,duration
< 30s
? (二 )breasts
? An increase in size and a nodular sensation due to the
hypertrophy of the mammary alveoli,the nipples soon
become larger,more deeply pigmented and more
erectile.scattered around the areola are some roundish
nodules called Montgomery tubercles which result from the
hypertrophy of the sebaceous glands.
? 三,circulatory system
? 1.heart:the growing uterus pushes the diaphragm
upward,with the result that the heart is displaced to the
left,upward and somewhat in the direction of the anterior
chest wall.a certain degree of rotation is believed to take
place.the capacity increases by 10%,the heart rate
increases by 10-15bpm.
? 2.output:increases from 10weeks,the peak at 32-34w.
? 3.Bp.:few changes if any,
? 4.venous pressure:increased vp,in the legs is
demonstrable in later months of pregnancy,which
contributes to the ankle edema,varicose veins in the legs
and vulva during gestation.
? Supine hypotension syndrom,supine position for a long
time → inferior vene cava compressed → back-
volume↓→ output↓→Bp↓→ cm,of hypotension.
? (四 )blood system
? 1.volume:increasing from 6-8w,peak at 32-34w,about
1500ml (1000ml of plasma,500ml of erythrocytes →
hemodilution)
? 2.composition,RBC→3.6*1012/L,Hemoglobin→110g/L,
WBC → 10*109-12*109/L,coagulating factors → most
inceasing → hyper-coagulation,plasmal protein
decreases mildly due to hemodilution.
? (五 ) urinary system
? both RPF,and GFR.increase by about 35% and 50%
respectively,the metabolites of the gravida /fetus can be
excreted.under the influence of progesterone,a condition of
atonia in relaxation or loss of irritability not only of
uterus,but also of the ureters,large bowel and bile
ducts→dilatation of ureters and renal pelvis associated with
stasis of urine → acute nephropyelitis especially in the right
side.
? (六 ) respiratory system:in a word,the ventilation volume
increases;the immunologic competence↓.
? (七 ) digestive sys:estrogen→gingiva-hyperplasia
progesterone→atonia of stomach and bowel→ heart
burn,vomit,constipation
? (八 )skin
? 1.the pigmentation of the areola,linea alba,vulva,occasionally
irregularly shaped,brownish patches of varying size appear on
the face and neck,the cloasma or the mask of pregnancy,which
fortunately usually disappears after delivery.
? 2.during late months of pregnancy,reddish,slightly depressed
streaks often develop in the skin of abdomen,and sometimes
also in the skin covering the breasts and the thighs.these striae
gravidarum occur in about 1/2 of all pregnancies.
? (九 )endocrine changes
? 1.pituitary gland:the anterior lobe hyperplasia
? (1)high level of E and P→inhibites Gn releasing
? (2)PRL:increases from 7w,peak ante-delivery
? 2.adrenalin cortex:the level cortisol and aldosterone increases
by 3 and 4 times respectively
Striea gravidarum
? 3.thyroid gland,the enlargement usually concomitant with
normal pregnancy due to hypertrophy of adenomatous tissue,to
an increase blood supply and to the formation of new
follicles.but most thyroxin is connected with thyroxin binding
globulin,so no hyperthyroidism occurs.
? (十 )metabolic changes
? 1.BMR:mildly rising,
? 2.weight,from 13w increases by 350g per week,about 12.5Kg
during the entire pregnancy.
? 3.metabolism of carbohydrate
? (1)fasting-sugar lower due to higher insulin-secretion
? (2)insulin-resistant factors
? 4.fat metabolism
? Deposit of fat increasing charaterized by a
hyperlipemia and a tendency to ketosis.
? 5.protein metabolism:positive nitrogen balance
? 6.water metabolism:water-retention of about 7L
? 7.mineral metabolism:in the late months of
gestation→
? calcium and iron supplying→to avoid deficiency of
calcium and iron.
? (十一 )bone,joint and ligament
? 1.bone:no changes normally.
? 2.joint and ligament:relaxin→loosening of joints and
ligaments→the birth canal widened.
thanks
Hegar
