Pregnancy – antenatal care

Introduction

• Much of the follow-up of pregnant women is carried out in the community, by midwifes at primary health care centres. The risk of death from pregnancy in the UK is roughly 1 in 20 000
• There are important screening and other investigations to be undertaken in the early stages of pregnancy – typically done by the general practitioner
• Antenatal care is also important for educating women and their families about pregnancy, childbirth and child care
• Most pregnancies are medically uneventful
• The degree of medical intervention in pregnancy varies quite widely between countries
• The exact measures will differ between NHS trusts, but below is a general outline of the type of care provided in pregnancy

Planning and pre-conception care

Assess Family plan

• What is the woman plan for her family?
• Any previous children?
• <18 months or >59 months between pregnancies is associated with worse outcomes, including pre-term birth, low weight, small size

Diet

The recommended diet is well-balanced, with plenty of fresh fruit and vegetables, starchy carbohydrates (e.g. bread, pasta, rice), dairy products and protein (including oily fish 2x per week, eggs and lentils).
Foods to avoid:

• Unpasteurised milk, soft cheese (and cheese with mould) , pate – can contain Listeria monocytogenes which may only cause a slight fu-like illness in the mother, but can result in miscarriage and still-births
• Raw eggs
• Pate of all kinds
• Uncooked (or undercooked) meat or fish and cold meat (and contact with cat litter) – can result in the contraction of Toxoplasmosis which can cause neurological defects
  • Salmonella is not known to cause any long term effects
• Vitamin A – see below
• Unwashed fruit and vegetables
• Tuna – is ok is small amounts (<4 tins per week), but it contains mercury which is teratogenic
• Too much fish – although fish is recommended, you should have no more than two portions per week – as many fish can contain pollutants, and eating too much can concentrate these molecules. Some sea foods are not risky, notably – shellfish and prawns.
  • Avoid shark, marlin and swordfish due to high mercury levels
  • Avoid uncooked shellfish

General advice on food preparation – wash all foods thoroughly, and cook all meat thoroughly, including cooking ready-prepared chilled meat.

• Listeria is a bacteria found on food
  • In pregnancy it has a 30-50% fetal mortality rate
  • Found particularly in unpasteurised diary, soft cheeses, cold meats, raw seafood, pate, ready to eat chilled-foods and raw egg
• Toxoplasmosis
  • Typically carried by cats
  • Avoid cleaning out litter trays – delegate to another member of the household
  • If litter trays are in the house, wash them daily with boiling water after emptying

Weight gain

• Typical weight gain is about 12kgs
• Some mothers gain up to 20kg without adverse effects
• Weight gain is slow in the first half of pregnancy – up to 20 weeks it is typically only 3kgs
• From 20 weeks onwards, average weight gain is about 0.5kg/week
• From 36 weeks weight is often stable

Exercise

Exercise guidelines are no different fro pregnancy than for the general population. Recommended exercise should be moderate intensity exercise for at least 150 minutes per week – e.g. 30 minutes per day on at least 5 days per week of brisk walking or similar.

• Contact sports and scuba diving (decompression) should be avoided

Supplements

• FOLIC ACID – advised to be taken for 1 month prior to pregnancy pregnancy, and for the first 13 weeks after conception (500 mcg/day). It prevents neural tube defects (NTDs) and cleft lip and palate.
  • High risk mothers – previous NTD babies or FHx of NTDs / diabetic mothers / mothers on antiepileptcis / BMI >30 / mothers in whom administration does not begin until after conception – mothers should take 5mg of folic acid per day
• Iodine – women who are pregnant, breast feeding or considering pregnancy should take 150 mcg/day of iodine
  • Typically iodine and folic acid supplements come in combination products designed for pregnancy
• Vitamin A can impair folic acid absorption – and the two should not be taken in a combined supplement. High levels can also cause birth defects. Avoid too much vitamin A – check supplements, and avoid fish liver oil, avoid eating animal liver.  Max 700mg/day.
• VITAMIN D supplements are also recommended
  • In UK – for all women – 10mcg (400 units) daily
  • In UK – for those with dark skin – 40mcg (1000 units) daily
  • In Australia – those with dark skin Our limited sun exposure – 40mcg (1000 units) daily
• Many pregnant women also become iron deficient – thus recommending foods high in iron (e.g. read meat, breakfast cereals (fortified) green veg, bread (fortified).
  • Vitamin C can help the absorption of iron
  • Tea and coffee impair iron absorption and should be avoided at meal times
  • Iron supplements are not recommended for all pregnant women, as they can cause side effects (notably constipation), but many women do take them, either self-prescribing or through a clinician.
  • Women ARE encouraged to take iron in the run up to delivery to negate blood loss, and reduce maternal morbidity.
• Free vitamin supplements are available to some women (in UK) from low socioeconomic backgrounds. Consider offering on booking visit

Sex

• Not shown to cause any harm in pregnancy
• Some advise to avoid sex in placenta praevia and history of preterm rupture of membranes but there is no evidence that this alters the outcome

Alcohol

Alcohol can easily cross the placenta. Prolonged and excessive alcohol intake can result in foetal alcohol syndrome (FAS) – where the child suffers from intellectual and behavioural problems later in life. Advise to avoid alcohol completely – particularly in the first 3 months of pregnancy.

• Binge drinking >5U/per session– is particularly harmful
  • Not all women who drink heavily in pregnancy have babies with FAS
• It is not known how much alcohol is safe (if any)
• Even just a single exposure to alcohol during pregnancy has been associated with foetal alcohol syndrome

Caffeine

Excess caffeine should be avoided, but you don’t have to cut out caffeine completely. Excess caffeine is associated with low birth weight. The max recommended is 200mg / day (roughly equal to 1 bar of chocolate and 1 cup of instant coffee, or two cups of instant coffee, or two cups of tea. Filter coffee has up to 150mg per cup).

Peanuts

There is not clear evidence as to whether eating peanuts in pregnancy or during breastfeeding alters the risk of allergy at all. Previous advice was to avoid peanuts.

Smoking

Advise smoking cessation. In approximately 25% of pregnancies, the mother is a smoker. Smoking increases the risk of:

• Placental abruption
• Perinatal mortality
• Preterm delivery
• Premature rupture of membranes
• Placenta praevia
• Low birthweight
• Risk of miscarriage is doubled
• Reduction in the child’s reading age (under the age of 11)
• In women who do not want to or are unable to stop smoking, there are still benefits to a reduction in the number of cigarettes of smoked, as this decreases the amount of nicotine that crosses the placenta, and increases birthweight.
• Only about 17% of smokers will stop during pregnancy.

TORCH infections

The TORCH diseases are associated with adverse outcomes in pregnancy and efforts should be made to minimise risk of infection

• T – Toxoplasmosis
  • Avoid cat litter, garden soil, wash all fruits and vegetables, avoid undercooked and uncooked meat, avoid unpasteurised milk products
• O – Other – HIV, syphilis, varicella, mumps, listeria)
  • For listeria, avoid soft cheeses, pre-packaged salads, deli meats, and chilled or smoked seafoods
• R – Rubella
  • Check serology. If pre-pregnancy can vaccinate. If already pregnant – vaccine contraindicated (live vaccine)
  • Also consider checking varicella serology. The same vaccine recommendations apply as for rubella
• C – Cytomegalovirus
  • Also included in this category is parvovirus B19 – which causes fifth disease / aka slapped cheek syndrome. If high risk – e.g. young children at home or a childcare or healthcare worker encourage frequent washing of hands and wearing of gloves when changing nappies
• H – Herpes Simplex

Examination

• BP
• Cardiovascular examination
•  Weight and height for BMI calculation
• Cervical screening – ensure this is up to date

Vaccination

Consider the following in the pre-pregnancy period, if these are not up to date.

• Rubella
• Varicella
• MMR
• Influenza
• Diphtheria, tetanus, pertussis

Other Advice

• Reduce weight if obese – it is important to emphasise the benefits of doing this before attempting pregnancy. If obese at booking, thromboprophylaxis may be advisable. Weight loss during pregnancy should not be advised – it increases the risks of a small baby (which itself is a risk factor for obesity later in the child’s life) and increases the risks of post-natal complications.
• Control diabetes – advise patients that HbA1C should be <6.1
• Control hypertension
• Control other conditions
  • Hypothyroidism – is particularly important. The fetus doesn’t produce endogenous thyroxine until it is 12 weeks old, and a lack can result in neurological defects
• Check all medications – for teratogenic effects. Common examples include:
  • Paroxetine – SSRI – fetal heart defects (particularly in first trimester)
  • Lithium – Mood stabiliser – used mainly in bipolar disorder – also associated with heart defects (Ebstein’s abnormality – tricuspid valve leaflets stuck to walls ofventricle)
  • Warfarin
  • Retinoids – structurally similar to vitamin A
• Counselling
  • E.g. if known to be at high risk of birth defects (e.g. sickle cell disease) then counselling should be advised as to the possibly outcomes, tests and options (e.g. termination)
  • Always remember, when advising for a test, always make sure that the patient understands what the results will mean, and, the implications of positive and negative results.
• Recreational drugs have serious implications for development and should be avoided
• Work – some types of employment are associated with poorer outcomes. For example a job that involves prolonged periods of standing can increase the risk of prematurity, hypertension and pre-eclampsia.

Timetable

• 10 for nulliparus women
• 7 for parus women
• More for those with diabetes

• BP and urine dipstick for ketones and glucose – for pre-eclampsia
• Offer the patient to ask about any questions and concerns
• Ask about any special arrangements for the birth – e.g. who would she like to be present, home birth, etc
• For most normal pregnancies, standard appointments are in the community, usually with the midwife

The combined screening test

There are typically two (and sometimes three) ultrasounds performed during in pregnancy

• Dating scan – typically 8-9 weeks – if dates are uncertain (NIPT usually performed)
• Combined screening test – USS and blood test performed between 11 and 13 weeks
• Fetal structural abnormality scan – performed at 18-20 weeks
  • Scan repeated at 32 weeks if placenta covers the cervical os

The combined screening test should be offered to all pregnancy women. This is a test performed around 12 weeks of gestation (quoted ins one places as between 11 weeks and 2 days and 13 weeks and 6 days) and screens for:

• Down Syndrome – trisomy 21
• Edward’s syndrome – trisomy 18
• Patau’s syndrome – trisomy 13
• False positive rate – <5% (I.e. specificity of >95%)
• Sensitivity – 85%

• The results are given as “1 in X” chance of the abnormality
• If the risk is greater than 1 in 250 – then the woman is offered further screening and ultimately may be offered the option of termination of pregnancy

The quadruple test – can only be done between 15 weeks 0 days, and 20 weeks 0 days – i.e. – in the second trimester. Looks at:

• Alpha FP
• Unconjugated estradiol
• BetaHCG
• Inhibin A – not widely available in the UK
• Woman’s age
• The test is not widely used in the UK, but can be useful for pregnancies presenting in the second trimester.

• Women should understand that the value calculated is only a risk. Even those with a low risk score could still have a Down’s baby. Those with a high risk score can still have a normal baby.
  • If the mother would not consider termination, even if the baby had Down’s, then consider if the test is actually any use
• Remember, it can cause a lot of anxiety in a lot of normal pregnancies!
  • The vast majority of those with a high risk combined test will have a NORMAL pregnancy

Chorionic villus sampling – if 10-13 weeks gestation

• In this procedure, a sample of the placenta is obtained, either by USS guided needle through the abdominal wall, or transvaginally.
• Complications
  • Miscarriage rate = 1-2%
  • Amniotic fluid leakage (<1%)
  • Sepsis (rare)
• Should not be performed before 10 weeks due to increased incidence of limb deficiencies
• Accuracy – diagnosis can be made in about 97% of cases
• Transabdominal procedure is easier, and yields better results than transvaginal

Amniocentesis – if >15 weeks gestation

• In this procedure, a needle is passed, usually under USS guidance, into the amniotic fluid, and roughly 10-20ml of fluid is aspirated (1ml for every week of gestation)
• Contains samples from fetal skin, urinary tract and lungs
• Rhesus prophylaxis should be considered
• Complications
• Miscarriage rate = 0.5-1%
• Amniotic fluid leakage – 3%
• Uterine bleeding – 2%
•  Maternal rhesus sensitisation
• Sepsis (rare)
• If amniocentesis is performed in the first trimester, miscarriage risk is 5% – hence the use of CVS in this period
• Diagnosis is quicker in CVS than in amniocentesis, but CVS is slightly less accurate
• Amniocentesis is safer than CVS – but can only be safely performed in the second trimester
• Cell culture in amniocentesis takes 3 weeks – thus any future termination date may be late! Results obtained sooner in CVS.

NIPT

Non-invasive Prenatal Testing

• A newer test, which uses a maternal blood sample to check fragments of fetal DNA (free fetal DNA)
• Like the traditional combined screening test, it test for trisomies 13, 18 and 21, and can also test for sex chromosome abnormalities
  • Chromosome abnormality tests also require a buccal screen from the father and are more expensive
• It is typically believed to be more accurate than traditional combined screening
  • Sensitivity and specificity >99%
• The test can be performed from 10 weeks gestation. There is no upper gestation limit
• It cannot be used in twin (or other multiple), donor eggs or embryos or women with previous bone marrow transfer pregnancies
• It is not a replacement for traditional combined screening
• It also gives a risk score – similar to the combined screening test – and like that test – it requires invasive testing to confirm the diagnosis (if suspected)
• In Australia it is sometimes advised for use in high risk pregnancies (typically risk greater than 1 in 300) to further stratify risk
  • It may help to reduce the need for amniocentesis – for example if a pregnancy is deemed high risk from a traditional combined screening test, and then found to be negative from a NIPT test, then amniocentesis could be avoided
  • It costs about $400AUD in 2019 but the cost is falling quickly
  • There are no formal guidelines on when it should be used. It might typically be used when the risk from a combined screening test is between 1 in 10 (these are very high risk and should be offered to proceed directly to invasive testing), and 1 in 250-300 (which is considered high risk). Those with a risk of less than 1 in 300 can be considered low risk
  • Some parents choose to pay privately for the test in low risk pregnancies also. This might particularly be the case in borderline high risk cases
  • I am unsure about its availability in the UK

Immunisations during pregnancy

• Influenza vaccine – can be given at any stage
• Pertussis booster – recommended after 28 weeks
• Typically both are given together around 28 weeks

Follow-up visits

A common follow-up schedule might include:

• The initial consultation at approximately 8-10 weeks
• Follow-up every 4-6 weeks until 28 weeks
  • e.g. 16 weeks, 22 weeks, 28 weeks
• Every 2 weeks until 36 weeks
  • e.g. 30 weeks, 32 weeks, 34 weeks, 36 weeks
• Weekly until delivery

The average number of visits in the UK is 10 for first time pregnancies and 7 for subsequent pregnancies. In Australia it is 12, however, there is a trend to fewer visit in recent years. Studies have found no difference in the detection of pre-eclampsia, UTI, low birthweight or maternal mortality between 6 and 12 prenatal visits

Each visit should include:

• Maternal weight
• BP
• Assessment of fundal height
  • Uterus remains in the pelvis until 12 weeks
  • Reaches the level of the umbilicus around 20-22 weeks
  • Reaches xiphisternum around 36-40 weeks
• Fetal heart
  • Detectable by stethoscope at 25 weeks
  • By Doppler at 18-20 weeks
• Fetal movements
  • Typically being around 16-20 weeks
  • Earlier in this period in subsequent pregnancies, often later in this period in first pregnancy
• Lie of the foetus (third trimester)
• Presence of oedema
• Urine for protein and glucose

Spontaneous miscarriage

• Occurs in about 10-15% of women aged 20-40.
• Occurs in 75% of women >45
• Overall average is about 15%
• It is not clinically significant unless a woman has 3 or more
  • If a woman has had 3 or more miscarriages, the risk of another is 45% (nullips under 35), or 35% for parous women.

Vaginal bleeding in early pregnancy

• Occurs in about 10% of healthy pregnancies
• However, is often also a sign of miscarriage
• Assesment:
  • <6 weeks – serial serum B-hCG. Should double every 2 days
  • If not rising at the rate – suggests a non-viable pregnancy (including ectopic pregnancy)
  • USS may visualise the gestation sac if B-hCG is >1500
  • 6-8 weeks – USS should be used to confirm pregnancy and rule out ectopic
  • >8 weeks – USS. Miscarriage rate after 8 weeks is <3%, UNLESS accompanied by a large amount of blood

Nausea and vomiting in pregnancy

• Affects more than 50% of women
• Typically goes away by the end of the first trimester
• Hyperemesis gravidarum refers to severe nausea and vomiting which may required admission to hospital for IV rehydration
  • Occurs in about 1% of pregnancies
  • Can cause electrolyte imbalances
  • More common with multiple pregnancies

Management

Lifestyle factors

• Small frequent meals
• Ginger
• Dry crackers first thing in the morning
• Carbonated drinks may alleviate symptoms
• Ensure sufficient hydration – sticks of water, sucking ice chips if necessary
• Avoid cooking smells
• Fatigue may worsen symptoms

Medical management

Proceed in a stepwise fashion with he list below. Additional agents can be added to the region of previously used medications

• Pyridoxine (vitamin B6)
  • 12.5mg morning and lunch, 25mg at night
• Doxylamine
  • 25mg at night initially (sedating)
  • Increase to 12.mg morning and lunch and 25mg at night (same dose as pyridoxine)
• Metoclopramide 10mg TDS
• Ondansetron 4-8mg TDS

Gastro-oesophageal reflux in pregnancy

• Particularly common in the third trimester
• Advise small meals frequently
• Consider elevated the head of the bed at least 15cm (e.g. with bricks or books)
• Regular antacids – e.g. Gaviscon – liquid may be more effective than sold preparations
• H2-receptor antagonists (e.g. ranitidine) are first line
  • PPIs are now also considered safe for pregnancy

Maternity leave in the UK

Women in the UK are entitle to statutory maternity leave of 52 weeks, if:

• They have been employed for 26 weeks by the same employer before they give notice of their maternity
• They earn >£95/week (roughly equal to >2 ½ full days per week on min. wage)

Statutory Maternity pay (SMP) is usually available for 39 weeks. Many employers offer their own benefits above this legal guarantee. The amount paid is:

• 90% of your wage for the first 6 weeks
• 90% of your wage, or about £125 (whichever is lower) for 33 weeks
• You should give 15 weeks’ notice – but the exact date can be changed with 28 days notice
• Maternity leave can begin from 11 weeks before the due date
• Compulsory Maternity leave – you don’t have to take all the 52 weeks, but you do have to take:
  • 2 weeks after the baby is born (most jobs)
  • 4 weeks after the birth if you work in a factory

Problems with the pregnancy – you can still take the statutory maternity leave if:

• Your child is stillborn after 24 weeks gestation
• Your child is a live-birth at any age, but subsequently dies

Working during Maternity leave – you can work for up to 10 days during maternity leave to help keep up to date with your job skills. If you work more than this, you lose your maternity pay for the week in which you worked.

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