Obstetric random stats

Question 1

Risk of cord prolapse

Answer 1

• 0.1/0.6%

- 1% in breech presentation

Question 2

Risk of placenta praevia

Answer 2

1:200

Question 3

Risk of caesarean hysterectomy in VBAC

Answer 3

0.06%

Question 4

Perinatal mortality in cord prolapse

Answer 4

91/1000

Question 5

Risk of PET in general population

Answer 5

2-3%

1.6 - 10 : 10 000

Question 6

Risk of Eclampsia

Answer 6

• 38% antepartum
• 18% intrapartum
• 44% postpartum

Question 7

Balanced translocation (13,14,15,22) stats

Answer 7

• In mother 1 : 8
• In father 1 : 40
• If either parent has “21” translocation the risk of Downs will be 100%

Question 8

Recurrence of neural tube defect

Answer 8

• 2 - 3 %

- Spina bifida: 1 - 5 %

Question 9

Fetal alcohol syndrome %

Answer 9

• 1 -2 : 1000

- 30 - 33 % women who drink > 18 units per week

Question 10

Congenital heart disease risk

Answer 10

• If you have one child: 1.5 - 5 %
• if mother has it: 2.5 - 18 % ( average 6 - 7%)
• If father has it: 1.5 - 3 %
• Mothers with ASD have a risk of 5-10% of their fetuses having the same
• Mother having aortic stenosis have 18-20% chance of their baby developing it

Question 11

Incidence of tetralogy of fallot

Answer 11

0.4 : 1000

Question 12

Incidence of Klinefelter

Answer 12

1 : 1000

Question 13

Incidence of trisomy 18

Answer 13

1 : 8000

Question 14

Risk of AFE

Answer 14

1 : 80 000 deliveries

Question 15

GDM recurrence

Answer 15

66%

Question 16

Peripartum cardiomiopathy incidence

Answer 16

1 : 1500 to 1 : 15 000

Question 17

Incidence of CAH

Answer 17

1 : 10 000 to 1 : 20 000

Question 18

Incidence of vit D rickets

Answer 18

1 : 20 000

Question 19

Congenital diaphragmatic hernia stats

Answer 19

• Mortality 40 - 62%

- Survival > 80%

Question 20

% velamentous insertion of the cord

Answer 20

1:100

Question 21

% pregnant population to have invasive testing

Answer 21

5%

30 000 women

Question 22

% complication of bloody tap during amnio

Answer 22

25:1000

Question 23

Maximum size needle for amnio at 15 weeks

Answer 23

20G

Question 24

Typical result of triple test for Down’s syndrome

Answer 24

• Reduced AFP
• Reduced oestradiol
• Increased hCG

Question 25

NSAIDS given in 3rd trimester gives what risk

Answer 25

Premature ductus arteriosus closure and pulmonary hypertension

Question 26

Mean corposcular volume which would need testing at booking

Question 27

Appendicitis surgery and fetal loss

Answer 27

- Strightforward appendicectomy: 1.5 % - With generalised peritonitis 6% - If the appendix perforates as high as 36% - Up to 35% of laparotomies may be negative

Question 28

Anaesthetic risks in pregnancy

Answer 28

- General anaesthetic carries a 17-fold higher risk of complications to the pregnant woman than regional anaesthesia - Failed intubation (in 3.3% due to pregnancy induced oedema, short neck, engorged large breasts) - Aspiration of gastric contents (Mendelssohn syndrome) - Hypoxia - Pregnant women desaturate far quicker than nonpregnant women (3 minutes as opposed to 9 minutes)

Question 29

% risk of enchephalopaty with pH

Answer 29

2.95 %