When implantation occurs, but the pregnancy fails to develop properly, it is called a chemical pregnancy. That's because you were technically pregnant (you produced the chemical HCG), but a normal pregnancy did not result. You see it as a regular period, or a period that is a few days late.

A chemical pregnancy is the clinical term used for a very early miscarriage. In many cases, the positive pregnancy test was achieved before the woman's period was due but a miscarriage occurred before a heartbeat could be seen on an ultrasound.

With the ultra sensitive pregnancy tests on the market today, it is easier than ever to get a positive result 3 or 4 days before your period is due. It is wonderful for those who NEED to know, but does have it's down side. Early testing shows chemical pregnancies that would not have been detected had the woman waited for her period to arrive.

Chemical pregnancies are unfortunately very common. 50 to 60% of first pregnancies end in miscarriage very early in pregnancy. Most occur without the woman even knowing that she was pregnant.

What causes a chemical pregnancy?

Low hormone levels: Women with lower level of hormones (Progesterone) or due to lack of hormones could find problems in continuing the pregnancy resulting in miscarriage.

Infections: Rubella, toxoplasmosis, Sexually transmitted infections like chlamydia, cytomegalo virus, genital herpes and syphilis can result in a chemical pregnancy. Maternal immune system diseases like lupus is another cause of miscarriage

Thyroid disorders: Thyroid disorders like hypothyroid can cause a chemical pregnancy. Hence a woman with hypothyroidism must check the thyroid hormone levels if planing for a pregnancy.

Luteal phase defects: Luteal phase is the phase between ovulation and periods. Usually the phase would be for 14 days, but varies from 11-17 days. If the phase lasts less than 10 days, it is called a luteal phase defect and thought to be a possible cause of miscarriage.

What are the signs and symptoms of chemical pregnancy?

It would be really difficult to detect the signs of chemical pregnancies as normal pregnancy symptoms occur around 6 weeks at the earliest. Fatigue and nausea are early symptoms but would be known to a woman who has been pregnant before. Symptoms like abdominal pain, blood clots in menses and prolonged or heavy menstruation suggest miscarriage.

Many women do not experience any signs or symptoms associated with this type of pregnancy loss. However, in some cases of chemical pregnancy, miscarriage symptoms can include the following:

* Tender breasts * Morning sickness * Nausea * Fatigue