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The principles of antenatal care |
Antenatal care ideally consists of:
- Pre-conception counselling
- Assessment of risk factors (including maternal health)
- Ongoing assessment of fetal well-being
- Ongoing assessment of complications
- Education about normal discomforts of pregnancy, emotional aspects
(including post-natal depression), local antenatal classes, reducing risk
of SIDS, parenting issues (including child-proofing the house and coping
with crying infants)
- Discussion of birthing care options
Risk factors
Assessment of risk factors largely occurs at the first visit. If it is not
possible to prolong the appointment confirming the pregnancy, it is as well
to re-book the woman for a double appointment. The date of onset of LMP
should be noted, but also the pattern of menses preceding this, as irregular
cycles or OCP withdrawal bleeds will make dating the pregnancy unreliable.
(If doubt exists then an ultrasound can be performed - the earlier the scan
the more accurate it is for dating the conceptus but the less accurate for
fetal morphology.) Also a full history and examination, including breast
& thyroid, and a Pap smear if not done recently.
Detailed history
As GPs we are ideally suited to obtain details of the woman's medical history
and examination, but also any financial and social aspects that may have
a bearing on the pregnancy. For example, previous history, or her personality
and lack of family supports, may put her at increased risk of post-natal
depression; in which case early involvement of social workers and mothercraft
services may avert a crisis.
Self-medication
A history of smoking, alcohol, and drug intake should be taken and
women advised not to self-medicate without checking first for safety. It
is worth specifically mentioning vitamin and herbal therapies as
some of these are to be limited in pregnancy, eg. Vitamin A>2500 I.U.
daily (>2 capsules) may cause birth defects; or avoided, eg. Golden Seal
which increases miscarriage rates. I would also recommend advising minimising
chemical and infection exposure in general - which includes occupational
exposure.
Diet
Dietary advice should focus on a well-balanced and varied diet with an emphasis
on complex carbohydrates and protein, and with adequate daily folate
(0.5mg, or 5mg if high NTD risk), iron (15mg), calcium (1200mg)
and fluids (2-3L). Foods likely to be contaminated with listeria
should be avoided eg. raw meat, raw seafood, soft cheeses. Many first trimester
women can minimise nausea by frequent small meals rich in B group vitamins
and low in spice and fat. Severe caloric restriction can result in reduced
fetal growth, so as a general policy weight reduction is best deferred to
post-natally.
Exercise
Exercise is commonly restricted to non-contact sports after 16 weeks,
and exercise intensity should be reduced by 25%, always followed by a cool-down
period. Core temperature should not exceed 38*C and HR 140/min, so ideally,
strenuous exercise should be limited to 15-20 minutes. Further, walking
more than five hours a day increases preterm labour risk by 1.4 compared
to les than two hours a day. (References available)
Ante-natal visits
Visits are usually monthly to 28 weeks, fortnightly to 36 weeks, then weekly
to delivery. Each visit should involved checks on maternal and fetal well-being.
As these are usually in a share-care capacity, a joint record card should
be carried by the woman to each visit. Cards can be obtained through any
public hospital stationery department and will record:
- Weight gain (12-15 kg in total, with 3kg in first 20 weeks)
- BP (a diastolic pressure>90, or increase of >20 from first visit
is significant)
- Urinalysis (watch for protein, glucose, and UTIs)
- Fetal movements
- Uterine size in accordance with dates and ultrasound
- Fetal lie, presentation, and engagement, especially after 36 weeks
Pathology tests
Certain pathology tests are routinely performed at intervals and the
current recommendations are:
- First visit: FBC, Blood group and antibody screen (BG), TPHA/RPR,
Rubella, MSU, Hep B and C, Pap smear if nil recent, and offer HIV screening
after counselling (NSW Health circular 95/44-A13866). Reinforce BSE.
- 10-12 weeks: Chorionic villous sampling if needed
- 15-18 weeks: Ultrasound, with serum AFP (or "triple
test" if considered appropriate). Amniocentesis if needed.
- 28 weeks: Hb and differential, BG, ferritin, modified GTT,
and low vaginal swab to exclude Group B strep. (Requiring intrapartum
antibiotic treatment to reduce neonatal morbidity)
- 36 weeks: Hb and differential, BG
(Other tests may also be indicated eg. TSH if goitre or Hb EPG
if thalassaemia suspected by low MCV.)
It is common to refer the woman for obstetric care after the 15-18 week
ultrasound has confirmed dates and fetal morphology, and thereafter care
is shared as dictated by the conditions of the pregnancy and the experience
of the GP concerned.
Common discomforts of pregnancy
These are worth mentioning and include:
- Pelvic pains, especially if lateral and referring to the upper thighs,
are usually due to ligamentous stretch. They require reassurance
only. Pain is reproduced by gentle sideways traction on an otherwise non-tender
and soft womb. Maximal 13 & 16 weeks.
- Urinary frequency is common but should be investigated as 8% of pregnant
women will have otherwise asymptomatic UTIs.
- Ankle oedema may relate to compression of inferior vena cava and to
vasodilatation due to increased hormones. If no associated proteinuria or
hypertension, it is best treated by rest with leg elevation, or natural
diuretics such as celery or Vitamin B6.
- Varicosities occur for the same reasons, and relief after confinement
can be dramatic. Once recognised, the early use of support stockings is
wise; while the short term use of pelvic elevation and ice packs can ease
the symptoms of vulval varicosities.
- Heartburn is due to gastro-oesophogeal reflux combined with increased
abdominal pressure. Postural and dietary advice with the use of antacids
settles most, but occasionally H2 antagonists (category B in pregnancy)
are required.
- Constipation can occur early so at least in part is due to hormones,
but is aggravated by enlarging pelvic contents. With the vasodilatation
and compression of pelvic veins this may result in haemorrhoids. Women should
be advised to increase their fluid and fibre intake, and if laxatives are
needed they should be of the fibre based type, eg. Metamucil or Fybogel.
- Low back pain is common due to altered posture; but also to the affects
of the hormone relaxin on ligaments, allowing excessive movement of sacro-iliac
and apophyseal joints. A regular exercise program, preferably swimming,
with physiotherapy as required, complements postural back care. Some women
develop symphysis-pubis pain, especially. If coexistent scoliosis, and may
require a s-p. Corset, obtainable through physiotherapy departments.
- Dental decay and periodontal disease accelerates in pregnancy and
should be reviewed by a dentist as early as possible.
- Skin changes include chloasma and spider naevi, which commonly disappear
after the pregnancy. The increased production of melanin in pregnancy may
lead to the diagnosis of pre-existent melanomas.
- Itch occurs in 17% gravid women. Interestingly, 50% women with atopic
dermatitis improve during pregnancy. If no rash, consider iron deficiency,
or the potentially more serious cholestasis of pregnancy. Antihistamines
may be helpful.
- Stretch marks may occur when growth has been rapid. The dryness and
irritation may be eased by vegetable oil or Vitamin E cream and soap avoidance.
Sue Page is a general practioner obstetrician in Lennox Head, NSW, Australia.
This page was last built on 10/01/03. It was originally posted on 12/4/98; 8:40:22 AM.
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