It can be incredibly frustrating to be able to fall pregnant but then miscarry. It is a drain psychologically and emotionally, as well as having a significant physical strain often needing hospital admissions and surgery. But perhaps even more important is the time it all takes. A pregnancy that results in a miscarriage at 8 weeks can take 3 or 4 months of precious reproductive time. As a woman gets older, this is almost like ‘time lost’ as egg numbers and egg quality are declining.
Overall, one in six of all pregnancies end in miscarriage, but this increases as a woman gets older (over 35). By age 45, the risk is 1 in 2. The vast majority of miscarriages are due to a genetic (chromosomal) abnormality in the embryo and is part of nature’s way of screening out potentially unhealthy babies. These cannot be prevented by diet, lifestyle modification or drug therapy.
Up to 3% of couples experience 3 or more miscarriages. This is called ‘recurrent miscarriage’ and may indicate other predisposing causes. A comprehensive investigation list would include:
- Male and female karyotype
- AMH LH, FSH, oestradiol
- TSH Prolactin, Testosterone
- FBC
- Cardiolipin antibodies, Lupus anticoagulant
- Protein C, Protein S, anti-thrombin III
- APCR
- Factor V Leiden
- Prothrombin gene mutation
- MTHFR mutation
- Fasting glucose, insulin, homocysteine
- Thyroid antibodies
- Peripheral blood activated natural killer cells
- Uterine natural killer cells and other endometrial pathology
- Pelvic ultrasound scan
- Hysteroscopy (and sometimes laparoscopy)
- Semen analysis and sperm DNA fragmentation
It is important to remember that this list of investigations would pick up an abnormality in about 50% of couples. In those in whom all tests are normal, the chance of next pregnancy being successful is high (60-70%), so those couples should still be very reassured by the normal results.
It is also worth noting that investigation is probably worth doing in women who have had 2 miscarriages and are over age 35 (as their time is diminishing), or one miscarriage in the context of IVF (given the significant costs and efforts involved in that), and also in anyone who is particularly anxious.
All couples suffering recurrent miscarriage should have early pregnancy monitoring in their next pregnancy (frequent blood tests and early scans) and progesterone support. Investigation abnormalities may indicate potential benefit from other therapies such as aspirin, clexane, high dose folate, metformin, prednisolone, thyroxine, menevit, DHEA, pelvic surgery, or IVF.
The IVF approach can be used to achieve a pregnancy more rapidly, to coordinate hormone and immune therapies more effectively, to assess embryo quality, or to screen for chromosomal abnormalities in embryos before implantation (PGD).