Wednesday, November 07, 2007

Need to know - Miscarriage

Gynaecologist Dr Roy Farquharson answers Dr Tonia Myers’ questions on miscarriage

1. What are the risks of first miscarriage? After a miscarriage, what are the odds of a further miscarriage/full term healthy pregnancy?

The risk of miscarriage is about 15% for each pregnancy. A further miscarriage is still 15% so the chance of two consecutive losses is 3%. Age-related effect is significant, especially over the age of 40 when the miscarriage increases year by year.

2. Can you read any significance into the timing of the miscarriage, for example is a loss at six weeks different from one at 12 weeks?

The type of pregnancy loss is important and has recently undergone revised classification according to gestational age and ultrasound findings. For instance a repeat fetal loss at 12 weeks gestation is more likely to be associated with maternal thrombophilia, for example antiphospholipid syndrome (APS).

3. What percentage of women who bleed in early pregnancy go on to miscarry? How is that figure altered by the detection of a fetal heart on ultrasound scan?

Vaginal bleeding of any description is common in early pregnancy. Overall, about 30% of all women in early pregnancy suffer vaginal bleeding which is not followed by miscarriage. Another 15% will miscarry in association with vaginal bleeding. The detection of fetal heart (FH) activity on scan is extremely important to the patient. At eight weeks the presence of FH activity is associated with a 95% success rate. By 10 weeks the success rate has risen to 98%.

4. Do all women who ‘spot’ or bleed in early pregnancy need their rhesus status assessing and, if rhesus negative, do they require anti D prophylaxis?

The present recommendations are provided on the Association of Early Pregnancy Units website at as well as the RCOG at .

In essence anti-D prophylaxis is not required with early pregnancy spotting unless heavy vaginal bleeding is present around or after 12 weeks’ gestation.
5. Current practice seems to be to moving towards allowing natural miscarriage rather than early ERPC for incomplete or missed abortion. What are the pros and cons for medical rather than surgical management?

The choice of management is driven largely by patient choice. It is a set standard that all cases of early pregnancy loss be diagnosed and managed within the early pregnancy unit (EPU) setting.

The MIST trial was an RCT comparing medical and expectant management with surgical management of first trimester miscarriage. Its results have provided a clear evidence base to support surgical, medical or conservative management and details can again be seen at the AEPU website.

Ideally a well-constructed and balanced patient information leaflet supported by empathic counselling will help the decision making process. PILS can be downloaded from the Miscarriage Association – see useful websites opposite.

6. After a silent miscarriage – previously called missed abortion – women sometimes request an early scan in their next pregnancy for reassurance. This clearly does not guarantee a positive outcome. How would you suggest we counsel these women?

For women with previous pregnancy loss, easy access to their local EPU is paramount in coping with the anxiety generated by a positive urine pregnancy test – although seeking help from a GP to organise an early scan shouldn’t be discouraged. All patients can locate their nearest EPU by logging on to the AEPU website home page.

7. In view of the psychological impact of miscarriage, along with the importance of dating a pregnancy, how long do you advise couples to ‘wait’ after a miscarriage before trying for a further pregnancy?

There is no set physical time limit. It is more a question of going through an appropriate bereavement process before contemplating the hazard of a future pregnancy and the associated anxieties. This can take three months or longer depending on personal circumstances and adaptation to the loss.

It’s not always best advice to say ‘wait for a normal period’.

8. What is your follow-up policy of a second trimester miscarriage?

Second trimester loss is a highly significant event. Many authorities recommend referral to a specialist regional miscarriage clinic for preconceptual assessment to exclude known causes such as cervical weakness, bacterial vaginosis and APS. About 10% of all late pregnancy losses will have two of these causes found.

9. Traditionally, it has not been policy to refer for investigation until after a third miscarriage. Knowing how distressing a second miscarriage can be, and with the advances in knowledge about causes and treatment of recurrent miscarriage, is this still appropriate?

The type of pregnancy loss is important in understanding what is an appropriate referral. In summary, one second trimester loss or two consecutive fetal losses before 12 weeks or three early losses before eight weeks reflects a reasonable consensus.

Following investigation more than 60% of couples show no abnormality on testing. However, couples with idiopathic recurring miscarriage (RM) should be encouraged as this is the best diagnostic group to be in for future pregnancy success compared with other causal diagnostic groups.

10. Can you tell me a bit about antiphospholipid syndrome? I understand the tests can be difficult to interpret.

Antiphospholipid syndrome (APS) is a well-known condition strongly associated with recurring miscarriage. Historically there was a simple thought that APS provoked placental thrombosis and hence fetal loss. It now transpires that a more complex and sophisticated process is in operation that affects the proliferation and differentiation of trophoblast (placental) tissue.

There are three tests that are used for diagnosis, one clotting test and two antibody tests.

The Dilute Russell Viper Venom Time (DRVVT) and/or anticardilipin antibody IgG and IgM fractions must be positive on two occasions more than six weeks apart for diagnosis confirmation.

All of these tests can be prone to quality control problems in their measurement. Consensus and accurate reporting between laboratories has been tackled but some concerns are still evident.

11. What do you tell women placed on antithrombotic agents about the bone risk?

The bone risk with heparin use has been studied in treatment and control groups. It would seem that pregnancy itself starts an immediate bone resorption phase which is slowly followed after 20 weeks’ gestation by a bone formation phase. This results in a ‘physiological’ bone loss of about 3% of the lumbar spine bone mineral density (BMD).

In association with heparin use another 1.5% is lost. Added to the average 6% bone loss associated with postnatal breast-feeding, there is a significant attrition to the maternal skeleton in genetically susceptible individuals who often have a strong family history of osteoporosis.

Before starting heparin in pregnancy a preconceptual BMD is advised in these individuals. The good news is that all mothers regain the bone loss over 12 to 18 months on average after delivery.

Roy Farquharson is a consultant gynaecologist at Liverpool Women’s NHS Foundation Trust


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