Pregnancy pathophyisology Flashcards
What are some common pregnancy disorders?
- Preterm birth (preterm labour, preterm premature rupture of
membranes — PPROM) - Placenta-mediated diseases
- Pre-eclampsia
- Intrauterine growth restriction (IUGR)
- Miscarriage
- Haemorrhage (antepartum, postpartum)
- Dystocia
- Metabolic conditions - Diabetes, hypertensive disease, obesity, thyroid
What is the link between birthweight and survival?
- Birthweight recorded globally
- Useful indicator of health
- Positively correlated with infant surviaval in the first year of life
- Low birthweight is associated with infant mortalitty
- Fetal growth charts
What is Preterm Birth?
- Leading cause of perinatal mortality/morbidity
- Incidence = 6-15%
- Delivery before 37 completed weeks gestation
- Global :
- 15 million babies born too soon
- 1 million deaths annually
- India, China, Nigeria, Pakistan, USA - currently 10% (2016)
- Societal cost = ~ £1 billion
What are some PTB complications?
- Respiratory disorders :
Lungs - lack of surfactant may cause tiny air sacs to collapse - A tube in the brain can reduce swelling and relieve pressure
- Artificial surfactant and air-delivery devices can help keep airways open
- Visual problems :
- EYES - Abnormal blood-vessel growth in the eye can lead to blindness = laser surgery can halt the vessel growth and preserve vision
- Retinopathy of prematurity
- Hearing difficulties
- Impaired neurocognition
- Periventricylar leukomalacia
- Neonatal sepsis
- SKIN - little fat, skin is thin and more transparent. May be yellow from jaundice . Incubators help babies who are born without a protective fat layer stay warm.
- GUT - intestinal tissue can die without beneficial mucus and bacteria. Intravenous nutrition bypasses the gut until it’s stronger
- Long term follow up - may face developmental delays later.,
What can cause PTB?
- Intrauterine infections :
- Mostly gram +ve bacteria :
- Ureaplasma parvum
- Ureoplasma urealyticum
- Streptococci
- Salmonella typhirium
- Gardenerella vaginalis (BV)
- Toxoplasma gondii
- Plasmodium falciparum (malaria)
- Candida albicans
- Adenovirus
- Bacteria infections can break away amniotic cavity
What are the inflammatory pathways that induce labour?
- Proinflammatory cytokines (TNF-a, IL-6) - raised in amniotic fluid/ cord blood
- Periodontal disease
- BV
- Ureaplasma ureakyticum, E.coli
- Any infection in the body has the capacity to induce PTB
How is Preterm Labour managed/ treated?
- Tocolysis - relaxing uterus
- Calcium channel blockers
- Atosiban (OTR antagonist)
- COX-2 inhibitors
- Nitric oxide donors
Prevention :
- Progesterone
- Cervical cerclage (stitches)
- Antibiotics
- Other channel modulators
CONS:
- No proven benefits for neonatal outcome
- None of the treatments have been developed for PTB
What is Preterm Premature Rupture of Membranes (PPROM)?
- Spontaneous membrane rupture before onset labour
- ~ 3% of pregnancies
- > 50% women with PPROM will deliver within a week
- Risk of intramniotic infection
- Fetal compromise caused by oligohydraminos and associated with a higher rate of C section
- Risk factors : choriodecidual inflammation, uterine distensionm smoking, cervical cerclage
- Detection/ diagnosis : positive fetal fibronectin test, short cervix
- Treatment : Antibiotics, antenatal corticosteroids
What is dystocia?
Dystocia
000/0 of all deliveries ( ‘v50% of CS)
Uterine dysfunction — incoordinate,
insufficient; inadequate muscle effort in
the second stage of labour — cervical
effacement and dilations, fetal descent
not achieved.
Abnormal fetal presentation, position
e.g. breech, transverse lie
Abnormalities of the maternal bony
pelvis e.g. cephalopelvic disproportion
Poor uterine activity may be stimulated
with oxytocin infusion
Dystocia leading cause of augmentation,
CS, instrumental delivery
Shoulder dystocia is more common in
fetal macrosomia, diabetes, maternal
obesity
What is pre-eclamspia?
- Persistently high BP arising from the start of pregnancy
- ~ 5–8% of pregnancies affected
- Distinct from pregnancy-induced hypertension (PIH)
- Multisystem disorder
- Hypertension - often proteinnuria and/or underlying renal function
- Early (<34 w) or late (>34 wk) onset. Latter less severe
Other symptoms : Oedema, epigastric pain, thrombocytopoenia, pulmonary oedema
- HELLP : Haemolysis, elevated liver enzymes, low platelets (thrombocytopenia)
What is the aetiology of pre-eclampsia?
- Poor invasion by cytotrophoblast
- Poor response to vasodilators
- Endothelial dysfunction
- Arteries do not dilate fully
- Endothelial damage
- ROS-lipid peroxidation
- May progress to eclampsia (‘lightning’)
- Risk factors : high BMI, new partner, first pregnancy, mother/sister had PE, preexistinf renal of cardiovascular disease
What is the treatment/ management of Preeclampsia?
- Low dose aspirin prohylactically
- Vitamins in pregnancy : no benefit with supplementation
- Magnesium sulphate for severe PE
- Delivery of placenta resolves PE
Future risk :
- Increased risk of stroke in pre-eclamptic mothers
What is fetal (Intrauterine) Growth restriction?
- The failure of the fetus to acheive growth potential
- Growth below tenth centike
- Small for gestational age babies
- Growth is normal or slows/ serial growth scans
- May coexist with PE (early onset)
- Shares aetiology with PE
- Symmetrical (chromosomal abnormalities, congenital infections, maternal drug use) vs Asymmetrical growth (Maternal hypertension, PE, Maternal vascular disease)
- Ethnicity smoking
- Difficulty in diagnosing
- ToRCH : Toxoplasma, Rubella, CMV can lead to IUGR
What is gestational diabetes?
- Glucose intolerance with onset pregnancy (16%, Diabetes UK)
- Insulin resistance (hormornal, fetal growth)
- Identified through antental screening
- Management (metformin)
- Macrosomia-increased glucose transport
- Increased maternal risk of type II diabetes
What are some risks of obesity in pregnancy?
Insulin resistance:
- Gestational diabetes
- Lifetime maternal diabetes
- Fetus = hyperglycaemia
- Birth injury
- C section
- Childhood obesity
- Vascualr injury
- CV disease
- Preeclampsia
- PTB
Inflammation
- cytokines
- adipokines
- lipids
- oxidative stress
