Common pathologies in pregnancy

Question 1

Physiology of pregnancy and fertilisation

Answer 1

• If an egg is fertilised then the progesterone continues to rise
• Progesterone triggers thickening of the lining
• Progesterone turns the endometrium into decidua – increased vascularity
• Stromal cells enlarge and become procoagulant and stop bleeding
• Outer edge of chorion = trophoblast cells on the outside of fertilised eggs
• Trophoblasts produce B-hCG (beta-human Chorionic Gonadotrophin)
o Used in pregnancy tests
• B-hCG stimulates the ovary to produce progesterone throughout pregnancy and stops the decidua from shedding
• The fertilised egg burrows into the decidua

Question 2

Case 1 - MISCARRIAGE

Answer 2

Woman, 26 yrs, Missed period, Pregnancy test positive, Vaginal bleeding 7 weeks after missed period
Investigations - US scan = no fetus present, membranes and decidua lining of uterus is still there = miscarriage, Remaining tissue removed by obstetrician, B-hCG returns to normal (0)
Causes of Miscarriage: Unknown = very common, Chromosomal abnormality, Infection, Maternal issues, Ill-health, Trauma, Hormonal problems

Question 3

Case 2 - ECTOPIC PREGNANCY

Answer 3

Woman, 32 yrs, Missed period, 8 weeks pregnant – small amount of bleeding per vagina
Investigations - B-hCG raised, US scan = thickened lining of endometrial cavity, expanded fallopian tube on 1 side = ectopic pregnancy
Considered methotrexate, Opted for operative removal of fallopian tube.

Question 4

Case 3 = Ruptured Ectopic Pregnancy

Answer 4

Woman 23 yrs, Sudden severe abdominal pain, Collapse, Admission to A&E – pulse fast + BP low
Emergency Laparotomy - Several litres of blood in abdomen, Blood flowing from fallopian tube area, Microscopy = blood, fragments of fallopian tube and occasional chorionic villi = confirms pregnancy

Question 5

Ectopic Pregnancy

Answer 5

• Pregnancy in the wrong anatomical site, Most common in fallopian tube, Lack of proper decidual layer and small size of tube, Predisposes to haemorrhage and rupture - Early presentation, woman may not even know she is pregnant.

Question 6

Case 4 = DM in pregnancy

Answer 6

28 yrs mother, Poorly controlled diabetes mellitus, Pregnancy doing well until 36 weeks – baby stops kicking
Scan - No fetal heart movement = IUD, IUD = Intrauterine Death, Stillbirth
Postmortem = Huge baby with broad shoulders, ‘Diabetic cherub’
Why is the Baby Big?
• Increased glucose in the mother – glucose crosses the placenta
• Insulin in baby increases but can’t reduce blood glucose because it keeps coming from the mother
• Longterm high insulin + high glucose = massive growth

Question 7

Diabetes in Pregnancy

Answer 7

Malformations, Huge babies that obstruct labour, Intrauterine death, Neonatal hypoglycaemia – high blood insulin and sudden cut off from glucose supply, Need good glucose control before conception and all the way through conception

Question 8

Case 5 = Mother infection

Answer 8

33 yrs, Well throughout pregnancy, 38 weeks spontaneous labour (normal), Labour progresses well but mother develops fever, Baby born distressed with poor Apgar score – transferred to neonatal unit, Baby resuscitated, well after 5 days, no malformations
Ascending Infection - Perineal or perianal flora, Ascend vagina and get into the amniotic sac
Examination of Placenta- Acute inflammation = neutrophils present in membranes, cord and fetal plate of placenta
Presentation of Ascending Infection - Mother ill = has fever and raised neutrophils in blood, Mother well = no kicking of baby on, no heart beat on scan, Baby unwell = ill in first few days of life, Baby well at birth = cerebral palsy later in life
Effect on Ascending Infection on the Baby - Neutrophils produce cytokine storm, Activates brain cells which get damaged during the normal hypoxia of labour