LEC49: Late Fetal Period & Twins Flashcards Preview

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Flashcards in LEC49: Late Fetal Period & Twins Deck (66)
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1
Q

fragment of time OBGYNs measure trimesters by

A

weeks, not months

2
Q

1st trimester time pd

A

weeks 1-13

3
Q

2nd trimester time pd

A

weeks 14-27

4
Q

3rd trimester time pd

A

weeks 28-40

5
Q

what occurs during 1st trimester

A

major organ systems form

6
Q

what occurs during 2nd trimester

A

fetal growth, differentiation- organ systems develop ability to take on roles, fxns as they should in a born baby

7
Q

ultrasound fxn

A

allows to visualize fetus, see anomalies

8
Q

when is fetus viable

A

24 weeks from LMP, end of 2nd trimester

9
Q

when is fetus peri-viable?

A

23 weeks

may survive

10
Q

what occurs during 3rd trimester

A

continued growth, maturation, development of embryo

11
Q

why is it important to accurate date pregnancy?

A

many things occur at very specific times during pregnancy so must know accurately how old fetus is

12
Q

when can visualize fetal heart beat on U/S?

A

6 weeks from LMP, 4 weeks since conception

13
Q

what are carnegie stages?

A

why to visualize embryonic pd of fetal development - til 8 weeks, 10 weeks from LMP
visualize by morpholgy, not just by age

14
Q

CRL

A

crown-rump length: measure from crown of head to rump- accurate for dating fetus within 3-5 days

15
Q

when can use CRL?

A

7-13 weeks

16
Q

weeks 9-12 features

A

1) head = 1/2 CRL of fetus
2) eyes fused
3) ears low
4) see some ossification cts appear in skeleton

17
Q

when do primary ossification cts appear?

A

end of 12th week

18
Q

weeks 13-16 highlights

A

1) coordinated limb movements
2) ossification of skeleton active
3) scalp hair patterning determined
4) genetalia recognizable
5) eyes anterior

19
Q

17-20 week highlights

A

1) mother feels movement
2) skin covered w/ vernix
3) fine lanugo hair present
4) brown fat forms- heat production
5) anatomy US routinely performed

20
Q

what is vernix

A

waxy white protection over skin

appears weeks 17-20

21
Q

why might baby at 24 weeks have trouble w/ heat production

A

brown fat hasn’t formed

22
Q

when is uterus at level of umbilicus/bellybutton?

A

20 weeks since LMP

1 cm from pubic symphysis=1 week

23
Q

21-24 weeks features

A

1) skin wrinkled, translucent
2) beginning of surfactant production
3) viability est

24
Q

26-29 weeks features

A

1) lungs more developed
2) CNS can control rhythmic breathing, body temp
3) eyelids open at 26 weeks
4) subcutaneous fat

25
Q

30-34 weeks features

A

1) skin pink, smooth
2) 32 weeks decreased risk of bleed in brain
3) majority survive

26
Q

when do eyelids open

A

26 weeks

27
Q

when is preterm

A

< 27 weeks

28
Q

when is early term

A

37-38+6 weeks

29
Q

when is full term

A

39-40+6 weeks

30
Q

when is post term

A

42+ weeks

31
Q

biggest risk factor for having a preterm birth?

A

if mom has prior hx of having preterm birth

32
Q

all risk factors for preterm birth?

A

1) prior preterm birth
2) uterine anomaly
3) multiple gestation
4) excess amniotic fluid
5) cigarettes/drug use
6) intrauterine infection

33
Q

how to treat woman who has had prior preterm birth?

A

progesterone-like injections

34
Q

diabetes effect on fetal growth?

A

if mom has diabetes, excess sugar stimulates fetus to create growth factor; can get fetus that’s TOO BIG or too SMALL

35
Q

what factors might restrict fetal growth?

A

1) vascular disease
2) hypertension
3) cigarettes
4) genetic disorders
5) anti-phospholipid antibody syndrome

36
Q

possible post-term issues?

A

1) increase in mortality
2) dry parchment-like skin, long nails, decreased vernix
3) meconium aspiration

37
Q

spontaneous incidence of multiple gestations in US?

A

twins: 1/80
triplets: 1/8,000

38
Q

why increase in multiple births nationwide?

A

use of ART, increase in maternal age

39
Q

what are dizygotic twins

A

twins from 2 diff eggs; each forms own amnion, chorion

40
Q

which type of twinning is familiar

A

dizygotic

41
Q

percentage of twins that’re dizygotic

A

2/3 twins

42
Q

is dizogytic twins maternal or paternal inheritance

A

maternal

43
Q

what is monozygotic twins

A

1 embryo that splits
if 4-8 day split, 1 placenta w/ 2 sacs
if 8-13 day split, 1 sac - risk for fetal death

44
Q

when do conjoined twins occur

A

after day 13, monozygotic twins

45
Q

is monozygotic twins inherited

A

no

46
Q

which has better outcome- dizogytic or or monozogytic twins

A

dizogytic twins

47
Q

hw might monozygotic twins present

A

2 separate amnions; 1 placenta w/ 2 diff sacs OR if split before day 4, 2 placentas w/ 2 sacs

48
Q

day 3-5 twin type

A

di/di

49
Q

day 5-8 twin type

A

mc/di

50
Q

day 8-13 twin type

A

mc/ma

51
Q

day 13+ twin type

A

conjoined twins

52
Q

what are monochorionic twins risk for?

A

1) fetal growth restriction
2) twin-twin transfusion syndrome
3) congenital anomalies
4) miscarriage
5) preterm birth

53
Q

degree of risk, least to greatest, re: twin type?

A

dizygotic
di and mono
mono mono

54
Q

complications of multiple births for baby?

A

1) preterm brith
2) low birth weight
3) neonatal morbidity and morality
4) congenital anomalies
5) chromosomal abnormalities
6) spontaneous fetal loss

55
Q

complications of multiple births for mom?

A

1) gestational diabetes
2) preeclampsia
3) cesarean delivery
4) maternal hemorrhage
5) acute fatty liver
6) placenta previa

56
Q

when did rate of twins peak in USA

A

1998

57
Q

when do singletons deliver

A

39-40 weeks

58
Q

when do twins deliver

A

35-36 weeks

59
Q

when do triplets deliver

A

33 weeks

60
Q

when do quads deliver

A

30 weeks

61
Q

what delivers earlier- multiple births or singleton?

A

multiple births

62
Q

complications of prematurity

A

1) hypothermia
2) patent ductus arteriosus
3) intracranial hemorrhage
4) hypoglycemia
5) respiratory abnormalities
6) necrotizing enterocolitis
7) infection
8) retinopathy of prematurity
9) learning disabilities, developmental delays, cerebral palsy

63
Q

risk of CP in multiple birth?

A

twins: 5x increased risk
triplets: 17x increased risk

64
Q

what factors increase perinatal morbidity, mortality?

A

fetal growth restriction and discordant growth

65
Q

why do dizygotic twins have great risk of chromosomal anomalies?

A

each twin has independent risk, whereas monozygotic twins have genetically identical risk
so 2x age related risk for dz twins

66
Q

what about ART might increase risk of chromosomal abnormalities?

A

sperm from subfertile men/women may increase risk of chromosomal and gene abnormalities w/ ART