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From time to time I give the local General Practitioners a question and answer session where we spend a few hours discussing problems that they may come across in their day to day work.

It is always fascinating to see that we all have similar problems with certain conditions. The standard of general practice in New Zealand is extremely high so when they have a problem you can be sure it is challenging for me to provide an adequate answer.

One of the most taxing day to day problems is that of a “Chemical Pregnancy”.

Now, what does that mean? In essence, it is a very early pregnancy.

When fertilization takes place the fertilized egg then makes it way down the fallopian tube into the uterus. Once there it implants and stars producing a hormone Human Chorionic Hormone or HCG. This can then be measured. Technology is so good now that even the most minute amounts are measurable. This is where we run into trouble. The test becomes positive and is quantitated early on when the levels are very low. Sometimes just too early. This is what is understood as being a chemical pregnancy.

As we know a large number of pregnancies fail and these very early ones fail the most. Often the HCG is measured even before a period is missed.

So one can understand the disappointment and frustration that emerges when in fact the pregnancy was doomed to fail anyway and if one waited for just a wee while longer then a period would ensue and we would all be none the wiser.

I don’t quite know what the answer is other than when an HCG is measured that early on one should be prepared for the possibility of a pregnancy failure.

As pregnancy is a dynamic event if one wants to know the pattern of progress HCG testing should be done about twice a week. Normally the level should double every 2 and a bit days until a level of somewhere around 30,000 is reached and then it plateaus or may even fall. By this time, however, a fetal heartbeat should be detected on ultrasound. If the pattern is not going up appropriately then the pregnancy may fail.

The HCG measurements do not obviously improve outcome but definitely, give us guidance as to how it is progressing until such time that the fetal heartbeat is seen ( somewhere around 6 to 6  and a half weeks.)

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