OBS - Chronic Conditions & Infections

Question 1

Chronic Conditions/Medications in Pregnancy

Hypothyroidism
Hypertension
Epilepsy
Rheumatoid Arthritis

Answer 1

1. ) Hypothyroidism
   - levothyroxine crosses the placenta so need to increase the dosage by 25-50mcg based on the TSH (should be <2.5 in pregnancy) to prevent:
   - anaemia, SGA, pre-eclampsia, miscarriage
2. ) Hypertension - medications may need changing
   - teratogenic/contraindicated: ACEi, ARBs, (thiazide)-like diuretics
   - safe: labetalol, CCBs (e.g. nifedipine), alpha-blockers
   - other beta-blockers disrupt placental blood flow which can cause FGR, hypoglycaemia, bradycardia
   - ACEi/ARBs can cross the placenta and reach the fetus’ kidneys to reduce urine production –> oligohydramnios
   - this can also lead to renal failure and hypotension
   - also causes hypocalvaria, miscarriage or stillbirth
3. ) Epilepsy
   - increased risk of folate deficiency so should all take 5mg of folic acid daily from before conception
   - seizure control may worsen (↑stress, hormones) but seizures are not harmful to the pregnancy
   - ideally, should only be on 1 AED before pregnancy
   - safe: levetiracetam, lamotrigine and carbamazepine
   - all the AEDs are safe during breastfeeding
   - sodium valproate causes neural tube defects and developmental delay and absolutely contraindicated
4. ) Rheumatoid Arthritis
   - ideally should be well controlled for at least 3mths before becoming pregnant
   - mother and father must have stopped methotrexate for at least 6 months before trying to conceive
   - sx often improves during pregnancy, worsens after
   - safe: hydroxychloroquine (1°), sulfasalazine

Question 2

Other Medications During Pregnancy

~~~
NSAIDs
Opiates
Warfarin
Lithium
SSRIs
Other Contraindicated Drugs
Drugs Contraindicated Whilst Breastfeeding

Answer 2

1. ) NSAIDs - avoid unless really necessary e.g. RA
   - avoid especially in 3rd trimester as they can cause premature closure of the ductus arteriosus in the fetus
   - can also delay labour (inhibits prostaglandins)
   - aspirin is contraindicated whilst breastfeeding due to the risk of Reye’s syndrome
2. ) Opiates - can lead to neonatal abstinence syndrome (NAS) which is withdrawal sx in the neonate after birth
   - NAS presents 3-72hrs after birth with irritability, tachypnoea, high temperatures and poor feeding
   - codeine is contraindicated whilst breastfeeding
3. ) Warfarin - teratogenic and contraindicated
   - fetal loss, congenital malformations (craniofacial)
   - bleeding: PPH, fetal haemorrhage, intracranial bleed
4. ) Lithium - avoid unless antipsychotics have failed
   - particularly avoid in T1: linked with congenital cardiac abnormalities, especially Ebstein’s anomaly
   - if used, monitor levels every 4w (weekly from 36w)
   - toxic in breast milk so avoid breastfeeding
5. ) SSRIs - commonly used in pregnancy, risks are balanced against the benefits of the treatment
   - crosses the placenta, effect depends on trimester:
   - T1: congenital heart defects, ↑risk w/ paroxetine
   - T3: persistent pulmonary hypertension in the neonate
   - neonates can experience mild withdrawal symptoms

6.) Other Contraindicated Drugs
- statins, sulfonylureas (gliclazide), retinoids (inc topical) cytotoxic agents
- antibiotics: tetracyclines (Doxy), aminoglycosides (gentamycin), trimethoprim, sulphonamides (Co-trimoxazole)

7.) Drugs Contraindicated Whilst Breastfeeding
- antibiotics: ciprofloxacin, tetracycline, chloramphenicol, sulphonamides
- aspirin (Reye syndrome), sulfonylureas (hypoglycaemia)
- teratogenic: methotrexate and cytotoxic drugs
- affects CNS: lithium, benzodiazepines
- affects thyroid: carbimazole (hypo), amiodarone (hyper/hypothyroidism)

Question 3

Cytomegalovirus (CMV)

Clinical Features
Investigations
Management
Congenital Cytomegalovirus

Answer 3

1. ) Clinical Features - mostly spread via the infected saliva or urine of asymptomatic children
   - usually asymptomatic in immunocompetent patients
   - can occasionally produce a mild flu-like illness
   - some may develop a mononucleosis syndrome –> fever, splenomegaly and impaired liver function
2. ) Investigations - if maternal CMV is suspected:
   - viral serology: CMV specific IgM and IgG
   - presence of IgG in mother previously seronegative
   - the presence of IgM and low IgG avidity (<30%)
   - amniocentesis: used to diagnose CMV in the fetus, only after 21wks (functioning kidneys required)
3. ) Management - refer to fetal medicine specialist
   - maternal: nothing, if immunocompetent, anti-CMV drugs are teratogenic and toxic so, is contraindicated
   - fetal: no therapies and TOP can be offered, if declined will need serial USS to assess problems
4. ) Congenital Cytomegalovirus - problems include:
   - IUGR, microencephaly, chorioretinitis
   - hepatosplenomegaly, TTP, jaundice, DIC
   - if symptomatic –> high risk of mortality (20-30%)
   - if asymptomatic, there’s 10-15% risk of sequelae:
   - sensorineural hearing loss, visual impairment, and psychomotor developmental delay, seizures

Question 4

Parvovirus B19

Clinical Features
Investigations 
Management 
Complications
Fetal Hydrops

Answer 4

1. ) Clinical Features - transmitted by respiratory droplets or blood, often from kids with slapped cheek syndrome
   - usually asymptomatic in adults, may have symmetrical arthralgia (often PIPJs and/or knees)
   - in children: URTI, malaise, headaches, low fever
2. ) Investigations - viral serology when the mother has potentially come into contact with parvovirus B19
   - IgM antibodies indicate a recent infection
   - IgG antibodies indicate past infection/immunity
3. ) Management - refer to fetal medicine specialist
   - maternal: self-limiting, antipyretics and analgesia
   - maternal pre-eclampsia like syndrome: HTN + proteinuria w/ fetal hydrops and oedema
   - fetal: serial USS+doppler starting 4wks post-infection or at 16w repeated every 1-2w until 30w gestation, refer to a tertiary centre if evidence of fetal hydrops for intrauterine erythrocyte transfusion
4. ) Complications
   - increased risk of miscarriage and fetal death
   - fetal hydrops: abnormal accumulation of fluid in 2+ fetal compartments –> fetal heart failure and anaemia
   - mirror syndrome (maternal): HTN + proteinuria with fetal hydrops, placental oedema, maternal oedema
5. ) Fetal Hydrops - occurs when PB19 replicates within the erythroid progenitor cells of the liver and bone marrow causing faulty production of RBCs causing:
   - severe anaemia which leads to cardiac failure
   - ↑erythropoiesis –> portal HTN and hypoproteinaemia which causes the oedema
   - USS features: ascites, pleural/pericardial effusion, subcutaneous or scalp oedema, polyhydramnios

Question 5

Rubella

Clinical Features
Investigations
Management
Fetal Management

Answer 5

1. ) Clinical Features - transmit via airborne droplets in close contacts, the incubation period is 14-21 days
   - often asymptomatic, if not, may have vague sx:
   - malaise, headache, coryza and lymphadenopathy, diffuse fine maculopapular rash
2. ) Investigations - when suspected
   - viral serology: IgM = acute, IgG = immunity
   - amniocentesis: diagnosis of fetal rubella between weeks 12-20wks
3. ) Management - refer to a fetal medicine specialist
   - discuss with the local Health Protection Unit
   - women planning on getting pregnant should have had MMR vaccine, can test for immunity if unsure
   - maternal infection is self-limiting, infectious from 7 days prior to the onset of symptoms to 4 days after
   - the risk of vertical transmission to the fetus, and the likelihood of congenital rubella depends on gestation
4. ) Fetal Management
   - <12w: 90% risk of transmission and 90% risk of congenital rubella, it is reasonable to consider TOP
   - 12-20w: 45-55% transmission, 20% congenital rubella, consider TOP or USS surveillance of abnormalities
   - >20w: 45% risk of transmission but no additional risk of developing congenital rubella syndrome

Question 6

Congenital Rubella Syndrome

Present at Birth Features
Late-Onset Features

Answer 6

1. ) Present at Birth Features
   - CNS: learning disabilities, microencephaly
   - auditory: sensorineural deafness
   - ophthalmic: retinopathy, congenital cataracts
   - cardiac: pulmonary stenosis, PDA, VSD
   - haematological: thrombocytopenia, blueberry muffin appearance
2. ) Late-Onset Features
   - thyroiditis, DM, growth hormone abnormalities, behavioural disorders

Question 7

Chicken Pox (Varicella Zoster)

Clinical Features
Investigations
Management of Suspected Varicella Contact
Management of Maternal Chickenpox

Answer 7

1. ) Clinical Features - incubation period is 10-21d and infectious 48hrs before rash until crusted vesicles
   - fever, malaise and a pruritic maculopapular rash
   - rash becomes vesicular and crusts before healing
2. ) Investigations
   - chickenpox is a clinical diagnosis but if in doubt:
   - immunofluorescence of basal epithelial cells scraped from vesicle or PCR for varicella-zoster DNA
   - viral serology to determine immunity status
3. ) Management of Suspected Varicella Contact
   - IgG testing to confirm immunity status if there is no hx of a previous chickenpox infection (or unsure)
   - Tx: IV-VZIG OR Aciclovir: if not immune, give IV V-Z immunoglobulin (VZIG) within 10d of contact, and before any rash appears OR you can give oral acyclovir 7-14 days post-exposure
   - manage these women as infectious from 8-28days
   - varicella-zoster vaccine is contraindicated in pregnancy because it is a live-attenuated vaccine
4. ) Management of Maternal Chickenpox
   - PO aciclovir (800mg 5tds) if presenting within 24hrs of rash onset and at >20 weeks gestation
   - consider aciclovir prescription in mothers <20wks
   - safety netting for pneumonia, neurological signs and a haematological rash
   - refer to a fetal medicine specialist with serial USS from 5wks post-infection to identify fetal abnormalities

Question 8

Complications of Antenatal Chickenpox

Maternal Complications
Varicella of the Newborn
Fetal Varicella Syndrome

Answer 8

1. ) Maternal Complications - ↑mortality and morbidity
   - chickenpox infection is also associated with pneumonia, hepatitis, and encephalitis,
2. ) Varicella of the Newborn
   - significant risk if maternal chickenpox occurs within the last 4 wks of pregnancy (may be asymptomatic)
   - routes of infection: transplacental, vaginal, direct contact after birth
   - newborns have passive immunity for chickenpox if the mother has varicella antibodies so are unlikely to develop chickenpox from sibilings
   - treatment: VZIG +/- aciclovir
3. ) Fetal Varicella Syndrome - due to reactivation of the virus in utero as herpes zoster, only occurs if the fetus was infected before 20/28wks gestation
   - still, only 1-2% are affected, characteristics are:
   - skin scarring in a dermatomal distribution
   - eye defects: microphthalmia (small eyes), cataracts, chorioretinitis (choroid inflammation), optic atrophy
   - neuro: microcephaly, cortical and spinal cord atrophy, seizures, Horner’s syndrome
   - fetal growth restriction, hypoplasia of the limbs

Question 9

Group B Streptococcus (GBS) Colonisation

Pathophysiology
Clinical Features
Investigations
Prevention

Answer 9

1. ) Pathophysiology - GBS is a commensal found in the vagina or rectum of 25% of pregnant women
   - pathogen in GBS is Streptococcus agalactiae which is a g+ve chained coccus and facultative anaerobe
   - can cause GBS disease in the newborn as well as chorioamnionitis or endometritis in the mother
   - usually asymptomatic but in the presence of certain risk factors, can lead to infection in the newborn
   - risk factors: GBS in previous baby, prematurity (<37w), ruptured membranes >24hrs before delivery, pyrexia during labour, UTI caused by GBS in pregnancy
2. ) Clinical Features - sx if become infected
   - UTI: frequency, urgency, dysuria
   - chorioamnionitis: fevers, lower abdo/uterine pain, foul discharge, maternal/fetal tachycardia (intrapartum)
   - endometritis: fever, lower abdo pain, intermenstrual bleeding, foul discharge (occurs postpartum)
   - neonatal infection: pyrexia, cyanosis, difficulty breathing and feeding, and floppiness
3. ) Investigations
   - vaginal or rectal swabs
   - urine cultures if the woman has a UTI
   - screening: only for high-risk patients e.g. sx of UTI or chorioamnionitis during pregnancy, previous GBS baby, STI sx before pregnancy

4.) Prevention
- intrapartum IV benzylpenicillin (or clindamycin/vanc) at the onset of labour then 4 hourly until delivery if at high risk of GBS colonisation:
- GBS positive swabs, UTI caused by GBS, previous GBS baby, pyrexia during labour, premature labour, rupture of membranes >18hrs
- antibiotics are not needed in planned C-sections as
it is the rupture of membranes that exposes the baby