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

 Identification of Risk Factors

 Abnormal Features of Pregnancy

 Features of Underlying Diseases

 Pre-Pregnancy Counselling

    1. Pre-existing medical disorders eg. DM (poorly controlled DM in pregnancy can cause increased risk for congenital disorders)
    2. Family Hx or personal Hx of genetic or chromosomal disorders (eg. Muscular dystrophy transferred to offspring - organise later prenatal diagnosis or advise against pregnancy)

 AIMS

 ANTENATAL CARE

Care of the pregnant woman up to time of delivery

    1. Antenatal clinic visits
    2. Day centre / Hospital for Ix / monitoring
    3. In-Pt monitoring / Tx (eg. DM: need to start insulin Tx as in-Pt to monitor response to dose)
    1. Should commence in 1st trimester (does not have to be obstetrician, can be family physician)
    2. 4-6w visits up to 28w
    3. 2-4w visits up to 36w
    4. 1-2w visits up to 40w
    5. Weekly visits after 40w (at least)
    6. Normally not allowed to carry on past 42 w of gestation

Objectives

Screening

ROUTINE

Optional: HIV screening (need Pt's permission)

ADDITIONAL

Consultation / Referral

Components

Intervention

    1. Deterioration in maternal condition
    2. Deterioration in foetal condition
    3. Both
    1. Delivery before foetal distress
    2. Delivery under planned and controlled circumstances

Provision

    1. Obstetrician
    2. Family physicians
    3. Midwives (not properly trained in HK yet, used more commonly in West)
    1. Hospital clinics
    2. Maternal Child Health Clinics (currently DH, will be taken up by HA)

INTRAPARTUM CARE

Background

Objectives

 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

    1. Augmentation of labour (with oxytoxin)
    2. Partogram (dilatation of cervix, foetal path)
    3. Vaginal examination

FOETAL

    1. Auscultation for 1 min after contraction
    2. Continuous electronic monitoring: external transducer, scalp electrode
    3. Scalp blood sampling for pH (metabolic acidosis?)

Progress of Labour

    1. Uterine contractions
    1. Pelvic size / shape
    2. ST obstruction
    3. Eg. Distended UB
    1. Foetal size / engagement
    2. Cephalic presentation - position, flexion, asynclitism (increased diameter so labour is obstructed), moulding and caput
    3. Breech - extended / flexed / footling

INTERVENTION

    1. C section (minimise trauma to foetus, therefore used more than instrumental delivery)
    2. Instrumental delivery (if fully dilated) (increased change of damage to foetal skull / scalp)

NEW-BORN CARE

Resuscitation

    1. Planned attendance by personnel skilled in neonatal resuscitation at high risk deliveries is essential for effective resuscitation
    2. 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)
    3. 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)
    1. Clear aw
    2. Expansion and vent of lungs
    3. Ensure adequate CO
    4. Minimising oxygen consumption by preventing heat loss
    5. Baby wet due to amniotic fluid
    6. Therefore must dry baby first, then wrap in warm towel
    1. Assessment (Apgar score)
    2. Aw suction
    3. Ventilation (bay and mask, intubation and ventilation)
    4. External chest compression
    5. Drug administration
    6. Maintenance of temperature

Screening

PHYSICAL

BIOCHEMICAL (in HK)

(a) GDPD Deficiency

    1. Drug induced haemolysis
    2. Severe neonatal jaundice
    3. Infection induced haemolysis
    4. Favism
    5. Chronic non-spherocytic haemolytic anaemia
    1. Cord blood - metHb reduction of micro-assay method for enzyme activities (can ID heterozygous with extreme lyonisation)

(b) Congenital hypothyroidism

    1. Cord blood for TSH
    2. Elevated TSH, repeat T4 and TSH
    3. Cord blood TSH screening may miss thyroxin binding globulin deficiency, hypothalamic-pituitary hypothyroidism, low T4 with delayed rise in TSH
    4. These formed by paediatric endocrinologist

New-Born Care

Parental Counselling & Support

Disease Prevention

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