Pregnancy Overview

Question 1

what is a full term pregnancy?

Answer 1

40 weeks of gestation
actually 38 weeks since fertilisation

Question 2

when does the blastocyst implant into the endometrium?

Answer 2

around day 5-7

Question 3

which cells help invade into the endometrium?

Answer 3

trophoblast

Question 4

which hormones increase with pregnancy?

Answer 4

human chorionic gonadotrophin
oestrogen and progesterone

Question 5

what is the function of hCG?

Answer 5

maintains integrity of corpus luteum (mimics LH) to promote continued progesterone and oestrogen secretion and prevent menstruation

Question 6

where is hCG produced?

Answer 6

syncytiotrophoblast following implantation of the blastocyst

Question 7

when do the levels of hCG decline?

Answer 7

once the placenta is established

Question 8

when is the fetal period?

Answer 8

from 9 weeks to birth
represents rapid growth and physical maturation of organ systems

Question 9

what is the process of lung maturation?

Answer 9

-are not involved with gas exchange
-filled with fluid
-breathing movements are made which is expulsion of fluid into the amniotic sac via the trachea

Question 10

where is pulmonary surfactant secreted from?

Answer 10

type II pneumocystis from 24 weeks of gestation

Question 11

what is the function of pulmonary surfactant?

Answer 11

it facilitates lung expansion at birth and reduces surface tension

Question 12

what can be administered to stimulate lung maturation for preterm infants?

Answer 12

<34 weeks
glucocorticoids
synthetic surfactant can also be administered after birth

Question 13

what is the process of renal system maturation?

Answer 13

new nephrons formed until 36 weeks of gestation
-kidneys produce dilute urine but otherwise minimal function (placental fulfils role)
-fetus swallows 7ml- amniotic fluid per hour and produces 300mm/kg of urine per day
-oligohydraminos (too little amniotic fluid) associated with poor renal function

Question 13

what is the process of digestive tract maturation?

Answer 13

-not fully functional in foetus due to placenta but maturation of enzymes for digestion and absorption occurs
-Crypts and villi develop during weeks 8-24 of gestation then elongate with gestational age

Question 14

what is meconium?

Answer 14

-greenish mixture of shed interstitial cells, langur mucous and amniotic fluid
-babys first poo
-can get meconium in amniotic fluid due to detail distress - risk of aspiration by the foetus

Question 15

what is the process of fetal circulation maturation?

Answer 15

-haemopoeisis in the fella liver becomes dominant during the 2nd trimester
-most erythrocytes contain fetal Hb which has greater affinity for oxygen that adult Hb

Question 16

what is the ductus arteriosus?

Answer 16

During fetal life, the ductus arteriosus connects the pulmonary artery to the aortic arch but closes minutes after birth

Question 17

what is the foreman ovale?

Answer 17

The foramen ovale is a hole between the left and right atrium and takes several months to close after birth
These allowing most of the blood to bypass the fetal lungs where it is not needed (placenta fulfils gaseous transport)

Question 18

when do the endocrine glands start producing hormones?

Answer 18

second trimester
contributes to fetal development and labour

Question 19

what is the endocrine function during pregnancy?

Answer 19

Before birth, fetus has a very large adrenal cortexAdrenal gland produces steroid precursor for oestrogen biosynthesis by the placenta
fetal posterior pituitary gland secretes oxytocin from second trimester and levels rise during labour

Question 20

what hormone is secreted during labour which initiates contractions?

Answer 20

oxytocin

Question 21

where is oxytocin secreted from?

Answer 21

fetal posterior pituitary gland

Question 22

what are some maternal adaptations to pregnancy?

Answer 22

-resp volume and total volume increases
-maternal blood volume increases by 50%
-nutrient requirement increases
-glomerular filtration rate increases by 50%

Question 23

why does maternal blood volume increase?

Answer 23

Placenta removes blood from systemic circulation, erythropoietin/renin production induced to increase blood volume

Question 24

why does glomerular filtration rate increase?

Answer 24

Due to increased blood volume Accelerates excretion of fetal metabolic waste

Question 25

where is oestrogen produced during pregnancy?

Answer 25

fetal adrenal gland and placenta

Question 26

what is the function of oestrogen during pregnancy?

Answer 26

At end of third trimester oestrogen helps with stimulating labour/birth. Human fetus and placenta cooperate to produce oestrogens – fetal adrenal gland secretes androgens > converted to oestrogens by placenta

Question 27

what is the function of progesterone in pregnancy?

Answer 27

Essential for the continuation of pregnancy Also has a role in breast development

Question 28

what is the function of hCG in pregnancy?

Answer 28

Functionally resembles LH = maintains integrity of corpus luteum, promoting continued secretion of progesterone

Question 29

what are the functions of placental hormones in pregnancy?

Answer 29

Maintaining the pregnancy Fetal growth Breast maturation

Question 30

what is the function of Human placental lactogen (hPL) or human chorionic somatomammotropin?

Answer 30

Polypeptide hormone. Promotes growth and differentiation of mammary gland tissue for lactation Stimulatory function on maternal tissues (like growth hormone (GH)) – ensures glucose and protein available to fetus

Question 31

what is the function of relaxin?

Answer 31

Peptide hormone. Increases pubic symphysis flexibility and cervix dilation Suppresses release of oxytocin by hypothalamus and delays onset of labour contractions

Question 32

what is the function of placental growth hormone?

Answer 32

Suppresses/replaces maternal GH Enhances nutrient availability to fetus by stimulating lipolysis and gluconeogenesis (glucose production)

Question 33

how do hormones stimulate breast maturation?

Answer 33

Oestrogen promotes growth and branching of the ductal system Progesterone promotes development of lobules and alveolar cells to proliferate, enlarge and become secretory But no secretion = requires pituitary hormones postnatally

Question 34

what is parturition?

Answer 34

childbirth occurs through a series of strong rhythmic uterine contractions

Question 35

what is the maternal and fetal endocrine coordination during childbirth?

Answer 35

Progesterone levels reduce towards term Fetal pituitary secretes oxytocin which enters the maternal blood stream via placenta Maternal pituitary also secretes oxytocin Prostaglandin production by fetal membranes on top of oestrogen and maternal oxytocin

Question 36

what happens during the dilation stage of parturition?

Answer 36

-cervical ripening (softening) and dilation -frequency of myometrial contractions increases steadily -amniochorionic membrane ruptures and water breaks -by the end of stage 1 cervix is fully dilated to 10cm -longest phase, hours to days

Question 36

what is the positive feedback that occurs during labour?

Answer 36

Contractions begin at superior portion of uterus towards cervix and increase in force and frequency Stretching of cervix further stimulates oxytocin release

Question 37

what happens during stage 2, expulsion stage?

Answer 37

-Contractions strong and frequent -Mother feels urge to push baby out -May need episiotomy cut in perineum to prevent perineal tear -Minutes to 3 hours -Neonatal health assessed by Apgar score

Question 38

what is an Apgar score?

Answer 38

evaluates a baby condition at birth and response to resus: gives a clinical score depending on; -appearance (colour) -pulse -grimace (reflex irritability) -activity (muscle tone) -resp effort

Question 39

what is considered a normal Apgar score?

Answer 39

7-10

Question 40

what happens during stage 3 (placental stage)?

Answer 40

Active or physiological management (see NICE guidelines: Delivering the placenta) Active management = oxytocin injection and removal by midwife. Lower risk of haemorrhage. Physiological management = delivery up to 1 hour postpartum via contractions.