Pregnancy

From Ganfyd

Pregnancy impacts on all forms of medical practice, if only from a which comes first - a chicken or egg viewpoint

Staying Not Pregnant

Getting Pregnant

Before

The UK diet is short of folate, which is required for proper folding of the developing embryo. A supplement of 400mcg of Folate is advised, from before conception (a month is suggested) until the 12th week. Certain women should take a larger dose - 5mg.

Likelihood

(Also regarded as the risk of pregnancy in relation to Unprotected sexual intercourse (UPSI) and Post coital contraception (PCC)).

Conventionally stated as about a 25% chance of one act of UPSI between a fertile couple around the time of ovulation resulting in pregnancy.

If pregnancy has not occurred after 2 years it is generally agreed investigation is appropriate. The also general view that this should wait only until 1 year in the less fertile group of older women is pragmatically sensible and kind, but suggests the longer wait for the younger is a rationing principle.

See also Infertility and Assisted conception

After a miscarriage

Our research shows that it is unnecessary for women to delay conception after a miscarriage. As such the current WHO guidelines may need to be reconsidered. In accordance with our results, women wanting to become pregnant soon after a miscarriage should not be discouraged. There may be cases where a delay is desirable, for example if there are signs of infection, and women should be advised appropriately. Also, in a molar pregnancy, current guidelines advise delaying the next pregnancy for at least one year after treatment - Love et al.^[1]

During Pregnancy

Haemoglobin and Iron

The circulating blood volume increases during pregnancy. There is a greater increase in plasma volume than in red cell volume. The result is a reduction in measured haemoglobin. If the body stores of Iron are insufficient then a reduction in MCV will occur, and only if this occurs is supplementing the diet with Iron either necessary or useful.

Prescribing iron based on a reduced Hb with a normal MCV indicates a lack of understanding of physiology and pregnancy

Drugs in Pregnancy

The fewer the better as the risk of teratogenicity is unknown for many drugs.^[2]. In the UK, clinicians can contact the National Teratology Information Service (0191 232 1525) for the most up to date information on this subject.

Information about drugs and lactation is also available, e.g. at NHS Medicines Information website.)

Infections in pregnancy

Infections may cause problems in pregnancy.^[3]For example:

Rubella infection during pregnancy is teratogenic
Parvovirus B19 infection may cause foetal loss or hydrops foetalis
Herpes Varicella Zoster (chickenpox) can cause intrauterine infection, or serious neonatal disease

See HPA Guidelines "Guidance on the management of, and exposure to, rash illness in pregnancy".

Hepatitis B

At least 95% of children born to mothers infected develop chronic hepatitis B. Babies born to infected mothers should be immunised with hepatitis B vaccine. The baby should also receive hepatitis B immunoglobulin if the mother is positive for HBeAg or suffers acute HBV infection during pregnancy. These interventions should take place as soon as possible (within 24 hours). Additional vaccinations should take place at 1, 2 and 12 months of age. This vaccination schedule prevents infection in over 90% of cases. If the baby receives the first dose of vaccine at birth and completes the course, they can be breastfed.^[4]

Vaccination in pregnancy

Live attenuated virus and live bacterial vaccines (such as MMR and BCG respectively) should be avoided in pregnancy; but vaccination with other vaccines is safe and in some cases recommended.

In the UK influenza vaccination is recommended for all pregnant women, as early as possible in the flu season (and repeated in subsequent pregnancies/flu seasons); and, since 1 October 2012 a temporary programme has been in place to vaccinate pregnant women against whooping cough. (The programme is currently described as a temporary programme; it is possible that it will become permanent; but the barriers to bringing in a temporary programme, in response to an epidemic, are considerably lower than the barriers to adding a new vaccine to the routine schedule on a permanent basis.)

Tetanus is a relatively common and serious complication of pregnancy in which vaccination is not the norm, so women who have not received tetanus vaccine prior to pregnancy should be offered vaccination against this. (This is included in the vaccine used for the "temporary" pertussis vaccination campaign referred to above.)

Maternal hypertension

NICE guideline: Hypertension in pregnancy August 2010

There is a high risk of pre-eclampsia with:

Essential hypertension
Hypertensive disease during a previous pregnancy
Chronic kidney disease
Systemic diseases such as SLE or antiphospholipid syndrome
Diabetes mellitus

and a moderate risk with:

Age 40 years or older
Pregnancy interval > 10 years
BMI > 35 kg/m2
Family history of pre-eclampsia
M ultiple pregnancy.

This risk is mitigated by 75 mg of aspirin daily from week 12 until the birth of the baby.

Early Pregnancy

Antenatal Care

Work, maternity leave, and employment in pregnancy

This section needs to be expanded

According to the DirectGov web site:

If you are pregnant... Your employer must make a special assessment of the risks to pregnant mothers and their babies. If there are risks, your employer must protect you and your baby by:
adjusting your working conditions and/or hours of work
offering you other suitable work if there is any
suspending you from work for as long as necessary

If you are suspended you are entitled to full pay, including any bonuses you would have been paid. Your suspension should last until the risk to you or your baby has been removed.

There can be extra risks to the health of pregnant night workers. If you have a medical certificate saying that there's a risk you should be offered suitable day work. If none is available you can be suspended until the risk to health has passed. If you refuse reasonable alternative work your employer doesn't have to pay you.

(This DirectGov page referred to above has links to a lot of other information on pay, suspension from work, risk assessment, and so forth when pregnant.)

According to this DirectGov page:

When you tell your employer that you are pregnant your employer should review their risk assessment for your specific work and identify any changes that are necessary to protect you and your unborn baby's health. Your employer should involve you in the process and continue to review the assessment as your pregnancy progresses to see if any adjustments are necessary.

These risks might be caused by:

lifting or carrying heavy loads
standing or sitting for long periods
exposure to toxic substances
long working hours

Your employer must then either remove the risk or remove you from being exposed to it (for example, by offering you suitable alternative work). If neither of these is possible, your employer should suspend you from work on full pay.

Unsuspected Pregnancy

1:80 in one series of American adolescents^[5] and 1:300 in another series of pre-operative testing.^[6]

References

[0] Love ER, Bhattacharya S, Smith NC, Bhattacharya S. Effect of interpregnancy interval on outcomes of pregnancy after miscarriage: retrospective analysis of hospital episode statistics in Scotland. BMJ 2010;341:c3967

[1] BNF list to avoid

[2] Macmahon E. Investigating the pregnant woman exposed to a child with a rash. BMJ (Clinical research ed.). 2012; 344:e1790.(Epub)

[3] British Liver Trust Report on Hepatitis

[4] Azzam FJ, Padda GS, DeBoard JW, Krock JL, Kolterman SM. Preoperative pregnancy testing in adolescents. Anesthesia and analgesia. 1996 Jan; 82(1):4-7.

[5] Manley S, de Kelaita G, Joseph NJ, Salem MR, Heyman HJ. Preoperative pregnancy testing in ambulatory surgery. Incidence and impact of positive results. Anesthesiology. 1995 Oct; 83(4):690-3.

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