IB WCS 10
PERINATAL MEDICINE, ANTENATAL CARE & PRE-PREGNANCY COUNSELLING
T Lao & B Lam
O&G + Paediatrics
Thu 29-08-02
PERINATAL MEDICINE
Current Concepts
Early identification of risk factors and abnormalities or underlying diseases
Anticipation of complications
Maternal and infant mortality and morbidity can be reduced and the likelihood of an optimal pregnancy outcome is enhanced
Eg. Gestational diabetes: insulin - prevent effect of diabetes on mother and baby - eg. Birth trauma
This has therefore extended beyond the traditional confines of the labour and delivery period.
The care provided at different stages of pregnancy is described below.
Identification of Risk Factors
- Demographics: advanced age, obesity, short stature
- Post obstetric history: previous foetal loss
- Family Hx: medical disorders, inheritable disorders
- Marriage: consanguineous - eg. Married cousins - risk of autosomal recessive traits increased
- History of sub-fertility: polycystic ovarian syndrome, adequate Tx may help Pt to become pregnant, but increased risk for complications
- Past health: pelvic infection?
Abnormal Features of Pregnancy
- XS morning sickness: hyperemesis gravidaum ® sign of thyroid dysfunction, underlying uterine infection?
- Bleeding in 2nd trimester: not normal finding, increased risk of pre-term labour
- XS or poor wt gain: XS due to fluid retention (DM); Poor: growth restriction and pre-term labour
- Marked oedema
- Glycosuria: heavy or recurrent - suggests DM, increased in pregnancy due to lowered glucose threshold
- Proteinuria: exclude UTI, onset of HT in preclampsia
- Uterine size and date discrepancy: larger or smaller than date, clinical palpation can detect (US not always necessary), if persists, something is wrong. Different observers may find differences in recording size of uterus in record. Could indicate growth problem, leakage of fluid
- Multiple pregnancy
Features of Underlying Diseases
- High BP in early pregnancy
- Abnormal urinary findings: polycystic kidneys
- Abnormal physical signs on general examination - eg. Heart murmur (very common in pregnancy - RHD very uncommon therefore more murmur due to functional murmur)
- Neurofibroma: potential candidate for phaeochromocytoma, may develop HT
- Skin lesions
- Abnormal screening tests - eg. +ve VDRL (syphilis, or could be antiphospholipid syndrome - may be true or false positive test - therefore need to repeat tests and order further tests)
Pre-Pregnancy Counselling
- Interview with women and spouses before conceptions
- Arrangement by referral to special clinic: counselling takes 1/2 hour or longer
- Usually with specific questions
- Pre-existing medical disorders eg. DM (poorly controlled DM in pregnancy can cause increased risk for congenital disorders)
- Family Hx or personal Hx of genetic or chromosomal disorders (eg. Muscular dystrophy transferred to offspring - organise later prenatal diagnosis or advise against pregnancy)
- Previous children affected with hereditary disorders (offer prenatal Dx at early stage, offers option for termination)
- Previous bad obstetrics Hx (damaged cervix, uterine abnormalities)
AIMS
- Optimise control of underlying condition
- Prognostic assessment - eg. Chance of offspring affected by an inherited condition
- Advise on timing and preparation for conception - eg. Peri-conceptional folate supplement
- Further Ix - eg. Ab screening
- Commence Tx for disorders identified (eg. Aspirin for antiphospholipid syndrome)
- Arrangement for early prenatal Dx (eg. Previous child with haemophilia - offer counselling for current pregnancy)
ANTENATAL CARE
Care of the pregnant woman up to time of delivery
- Antenatal clinic visits
- Day centre / Hospital for Ix / monitoring
- In-Pt monitoring / Tx (eg. DM: need to start insulin Tx as in-Pt to monitor response to dose)
- Should commence in 1st trimester (does not have to be obstetrician, can be family physician)
- 4-6w visits up to 28w
- 2-4w visits up to 36w
- 1-2w visits up to 40w
- Weekly visits after 40w (at least)
- Normally not allowed to carry on past 42 w of gestation
Objectives
- General screening
- Risk factors
- Maternal disease
- Establish baseline for future comparison: Wt , BP
- Confirm gestational age and exclude foetal anomalies
- ID anomalies and complications: Eg. Static wt, increased BP
- Monitor maternal progress and foetal growth / wellbeing
- Decision for timing and mode of delivery: Eg. Breech baby - elective C section needs to be booked ahead of time (vaginal delivery not safe)
® usually assessed in last 2w of pregnancy (sometimes earlier if risk of pre-term labour)
Screening
ROUTINE
- Hb, MCV (for thalassaemia trait carriers)
- Blood group (ABO, Rh)
- VDRL
- HBsAg
- Rubella
- Cervical smear
- Urine for protein and glucose
Optional: HIV screening (need Pt's permission)
ADDITIONAL
- Renal and liver function
- OGTT
- Autoimm Ab
- MSU for culture and microscopy
- Vaginal / endocervical / rectal swabs for culture
- Thyroid function
- Coagulation function
- Complete blood picture and platelet count
Consultation / Referral
- Prenatal diagnostic team
- Anaesthetist: eg. C section
- Physician
- Paediatrician
- Paediatric surgeon: eg. Foetal anomalies that are operable - diaphragmatic hernia
- Psychiatrist
- Social worker: employment, divorce, accommodation, domestic abuse
- Physiotherapist: sciatica, pain, carpal tunnel
- Dietician
Components
- Medical assessment and Tx
- Educational classes
- Antenatal exercise (eg. Protect jt, enhance performance during labour)
- Nutritional advice and supplementation
- Social support - eg. Single mother, recent separation from spouse, eviction from home
- Psychological support - eg. Martial problem
Intervention
- Continuous assessment, revise previous decision if necessary
- Uncomplicated: allow spontaneous labour unless > 41w
- Complicated: terminate pregnancy if
- Deterioration in maternal condition
- Deterioration in foetal condition
- Both
- Delivery before foetal distress
- Delivery under planned and controlled circumstances
Provision
- Obstetrician
- Family physicians
- Midwives (not properly trained in HK yet, used more commonly in West)
- Hospital clinics
- Maternal Child Health Clinics (currently DH, will be taken up by HA)
INTRAPARTUM CARE
Background
Intrapartum course is critical for the final infant outcome (most complications occur in the peripartum period)
All low risk pregnancies can develop intrapartum complications (most obstetrics complications occur in low risk pregnancies)
Many post partum complications are related to intrapartum events / complications / Mx (Eg. Prolonged labour: if not Mx sufficiency, mother has change of profound haemorrhage)
Objectives
- ID compromised features, esp. in early labour, for prompt delivery
- ID the development of foetal distress for intervention
- Final assessment of the feasibility of vaginal delivery
- Minimise risk of trauma and asphyxia in the new-born
- Prevention and Tx of maternal complications
Previously many multiparous women
\ could compare current delivery to previous to see if she can delivery vaginally. Now, women usually have 1-2 babies \ no comparison
No scans of pelvis due to fear of radioactivity - cannot tell if pelvis will allow baby through
In addition, babies getting bigger due to better nutrition
These factors
® obstructed labour. However, C-section cannot always be performed: surgery, blood loss
Management
MATERNAL
- Manage as for ICU and monitor maternal vital signs
- Analgesia - Pethidine, epidural analgesia (pain tolerance decreased these days?)
- Hydration - IV fluid (labour strenuous + mother usually fasted ® ¯ risk aspiration pneumonia)
- Ensure adequate power and good progress
- Augmentation of labour (with oxytoxin)
- Partogram (dilatation of cervix, foetal path)
- Vaginal examination
- Set time limit for intervention for each stage
FOETAL
- Assess wellbeing at onset of labour
- Electronic foetal heart monitoring (admission test)
- State of amniotic fluid - clear, meconium-stained, blood-stained or nil (if nil, a bad sign - placenta not working properly)
- Continuous monitoring
- Auscultation for 1 min after contraction
- Continuous electronic monitoring: external transducer, scalp electrode
- Scalp blood sampling for pH (metabolic acidosis?)
Progress of Labour
- Uterine contractions
- Pelvic size / shape
- ST obstruction
- Eg. Distended UB
- Foetal size / engagement
- Cephalic presentation - position, flexion, asynclitism (increased diameter so labour is obstructed), moulding and caput
- Breech - extended / flexed / footling
INTERVENTION
- When foetus cannot tolerate stress of labour
- When spontaneous delivery is unlikely
- Before foetal distress / compromised
- Evidence of disproportion
- Maternal distress
- Means
- C section (minimise trauma to foetus, therefore used more than instrumental delivery)
- Instrumental delivery (if fully dilated) (increased change of damage to foetal skull / scalp)
NEW-BORN CARE
Resuscitation
Transition at birth is the most vulnerable period
Effective resuscitation of infants is extremely important because of the serious consequences of asphyxia
Anticipation of resuscitation
- Planned attendance by personnel skilled in neonatal resuscitation at high risk deliveries is essential for effective resuscitation
- All attendants in labour room should be equipped with basic skills of new-born resuscitation (all medical and nursing staff attend course every year - course run every 3m)
- Policy outline stand-by criteria and resuscitation plan is essential (also radiant heater- transfer from 37 degrees inside uterus to 20-something degrees outside, will shut down baby's peripheral circulation and won't be able to breathe)
- Clear aw
- Expansion and vent of lungs
- Ensure adequate CO
- Minimising oxygen consumption by preventing heat loss
- Baby wet due to amniotic fluid
- Therefore must dry baby first, then wrap in warm towel
- Overview of resuscitation in the delivery room
- Assessment (Apgar score)
- Aw suction
- Ventilation (bay and mask, intubation and ventilation)
- External chest compression
- Drug administration
- Maintenance of temperature
Screening
- ID of disease among the new-born by simple sensitive tests to sort out babies at risk from those are not affected
- Important aspect of preventative paediatrics
- Physical and biochemical screening
PHYSICAL
- Ensure neonate is in good health
- Take health growth measurements and to assess the appropriateness for the assessed gestational age
- Detect congenital malformations that require early medical attention - eg. CHD, congenital dislocation of hip, CNS abnormalities
- Give mother a chance to ask about her neonate and explain normal variation present, to assess the parental competence in baby care (eg. Birth mark, extra digits)
BIOCHEMICAL (in HK)
(a) GDPD Deficiency
- Incidence 4.42% male 0.45% female
- Prevalent in southern Chinese
- Clinical syndrome
- Drug induced haemolysis
- Severe neonatal jaundice
- Infection induced haemolysis
- Favism
- Chronic non-spherocytic haemolytic anaemia
- Cord blood - metHb reduction of micro-assay method for enzyme activities (can ID heterozygous with extreme lyonisation)
(b) Congenital hypothyroidism
- Preventable cause of MR
- Biochemical screening enable early Dx and prompt Tx to prevent MR
- Incidence in HK - 1:3200
- Reported incidence varies from 1:4500 to 1:6300
- Method
- Cord blood for TSH
- Elevated TSH, repeat T4 and TSH
- Cord blood TSH screening may miss thyroxin binding globulin deficiency, hypothalamic-pituitary hypothyroidism, low T4 with delayed rise in TSH
- These formed by paediatric endocrinologist
New-Born Care
- Promotion of baby-maternal bonding: decreases child abuse later in life
- Breast feeding: GIT protection, gastro-enteritis, reduce allergies and asthma
- Rooming-in for normal infants
- Temp control
- Wt change: baby loses some water after birth, oedematous
- Observation of vital signs
- Bowel and bladder activities: Hirschsprungs disease - patent anus but cannot pass stool
Parental Counselling & Support
- Establish good rapport with parent
- Open sensitive and information communication (make sure mother is coping OK, otherwise chance of post-natal depression)
- Advise on infant care - eg. Cleaning of umbilical cord, new-born sleeping pattern and position (avoid SIDS), sneezing, hiccup etc
- Reassurance and positive reinforcement
Disease Prevention
- Eye disease prevention
- Vitamin K prophylaxis against haemorrhagic disease of new-born
- Immunisation (first doses given before discharge; each mother given card with vaccination history to complete course)
- Hepatitis B vaccination: doses
- Hep B Ig
- BCG
- OPV: before baby leaves hospital
- Prevention of cross-infection in nursery
SUMMARY
Pre-pregnancy Counselling
This refers to one or more interviews with the potential mothers, and their spouses where necessary, before their attempts to conceive. The reason for such interviews are usually some pre-existing diseases such as diabetes mellitus, genetic or chromosomal disorders affecting the parents or previous children, and poor obstetric history. The aims are to optimise control of the underlying condition, to give a prognostic assessment, to advise on the best timing of conception, and to offer early prenatal diagnosis and intervention where necessary.
Antenatal Care
In the majority of women, there is no relevant medical history or family history. Regular and frequent visits to the antenatal clinic, ideally starting from the first trimester, will allow the obstetricians to screen for maternal diseases such as infections, to identify pregnancy-related complications at the earliest opportunity and hence to instigate appropriate treatment, to screen for foetal anomalies and confirm gestational age, to monitor maternal progress and foetal growth, and to decide on the best timing and mode of delivery where indicated. The routine antenatal screening tests include haemoglobin and mean cell volume (for thalassaemia traits), ABO and Rh blood groups, VDRL, Hepatitis B, rubella and HIV status, and cervical smear. Additional tests are performed for women with various risk factors or relevant past history or family history, such as the OGTT, autoimmune antibodies, vaginal swab and urine cultures etc. For women at high risk of operative delivery and/or anaesthetic procedures, consultation with the anaesthesiologist is arranged in the third trimester.
Intrapartum Care
The intrapartum period is managed as in the case of a patient in intensive care. Close maternal and foetal monitoring are adopted for both the low-risk and high-risk pregnancies, because the majority of obstetric complications in fact occur in low-risk pregnancies. Even in the absence of maternal or foetal distress, a time limit is usually set for the duration of the different stages of labour so that appropriate interventions will be undertaken when indicated.
Neonatal Care
The newborn is cared for immediately after birth, and in the case of suspected foetal distress or high-risk conditions such as pre-term labour, a paediatrician will stand-by for resuscitation at the time of delivery. New-borns requiring observation or special care are admitted into the neonatal unit for management. All new-borns are routinely screened for hypothyroidism and G6PD deficiency. They are examined daily after delivery and are checked by the paediatricians again before discharge so that abnormalities can be detected and early medical attention be given. The new-borns are roomed-in with their mothers and breast-feeding is encouraged