Q. Why do I have pregnancy sickness?
Medical research has shown an association between the pregnancy hormone human chorionic gonadotrophin (hCG) and pregnancy, although this association only holds true when several women are grouped together in the investigation, rather than for each individual pregnant woman. In addition, high maternal blood levels of this hormone occur in twin pregnancies and twin pregnancies are generally associated with increased pregnancy sickness. A rare condition in the Western World is a Hydatidiform Mole, in which the afterbirth is abnormal, but more significantly, there is no normal baby present. This condition is also known to be associated with a high maternal human chorionic gonadotrophin blood levels and increased pregnancy sickness. As there is no baby present, the sickness cannot arise from the baby. There is one other pregnancy related condition in which high blood levels of hCG occur in the woman’s blood, but this condition is not associated of itself with any sickness. Therefore, neither the baby nor hCG itself can be the cause of pregnancy sickness. HCG can be considered to be associated with nausea and vomiting of pregnancy (N.V.P.) but not its actual cause.
It is remarkable that the hormone hCG has, by electrophoresis, been shown to occur in at least 5 different isoforms or ‘types’. In very early pregnancy, the type with an ‘acidic basis’ is more prominent, whereas, after 11-15 weeks of pregnancy the more ‘basic’ type of hCG becomes the more prominent of the isoforms. It has been shown that the acidic type of hormone is the most active form of the hormone, but it is more quickly broken down to become ‘inactive’ than the basic type. This active acidic type of hCG has been shown to be present in higher quantities in women who have hyperemesis gravidarum (the most severe form of pregnancy sickness) than in normal pregnancy.
If hCG itself is not causing pregnancy sickness, though associated with the condition, perhaps because the maternal blood level of hCG is rising rapidly in early pregnancy, some other hormone which stimulates hCG production in early pregnancy, may cause pregnancy sickness. At present, we know of eleven locally acting hormones which stimulate the secretion and release of hCG from afterbirth cells. The only two of them known to cause sickness in pregnancy are called Prostaglandin E2 and F2alpha. One further investigation has shown that more Prostaglandin E2 is present in maternal blood when pregnant women are feeling sick than when they are not feeling sick on the same day. Obviously, more investigation is needed into this under-funded and under-researched condition before we can be definite about the association of acidic hCG and Prostaglandin E2 with pregnancy sickness. It may be that we have been able to show there is grounds for believing pregnancy sickness is a physical hormone based condition, rather than purely a somatic or mind over matter reaction to a stressful condition.