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A.Hyperemesis gravidarum is the medical name for a very severe form of morning sickness. It is uncommon occurring in less than 1 in a 100 pregnancies. It usually starts between six and eight weeks from the last menstrual period and tends to continue until about 20 weeks. Occasionally it can last throughout the pregnancy. Morning sickness becomes hyperemesis when the mother has persistent nausea with vomiting several times a day leading to dehydration, with a biochemical upset in her body and inadequate nutrition leading to weight loss. It tends to recur in subsequent pregnancies, so if a mother has had it once she is likely to have it again. Sometimes there is also a mild upset of liver function. Doctors don’t yet know why hyperemesis occurs. However, it is known that there is a relationship between high levels of a substance called HCG, which is produced by the afterbirth (this is the hormone that a pregnancy test detects). This may be why hyperemesis is more common in twin pregnancies as with two placentas the level of HCG will be much higher than with a single baby. High levels of HCG occur in the first 3 months of pregnancy then levels start to decline. Morning sickness and hyperemesis occur over this same period. These high levels of HCG in the blood can cause the thyroid gland to become slightly overactive on a temporary basis and this might be one of the ways that nausea and vomiting is produced. Another possible cause is stomach infection with the bacteria called Helicobacter pylori, which causes stomach ulcers. A psychological component to hyperemesis has also been proposed.

Hyperemesis gravidarum can be a very serious condition if not adequately treated. Complications such as deficiency of B vitamins, dehydration and malnutrition can occur. There is a higher risk of blood clots in the veins with bedrest and dehydration associated with severe vomiting in pregnancy. Such complications can be dangerous for the mother. Despite the severe metabolic upset that can occur with hyperemesis gravidarum, there is no evidence that this will lead to an increased risk of abnormality in the developing baby. However, in very severe cases where women lose more than 5% of their bodyweight, there is a higher chance of the baby being small compared to uncomplicated pregnancies or pregnancies with mild morning sickness. Women with hyperemesis gravidarum are usually admitted to hospital. Treatment includes fluids given through a vein to rehydrate the mother, vitamin supplements and medication to reduce the nausea and vomiting. Steroid medication has been shown to be effective in severe cases. Occasionally intravenous feeding is required. Medication can also be given to reduce the risk of blood clots. If you have severe morning sickness or think that you have hyperemesis gravidarum you should seek advice from your doctor or midwife as treatment can improve the situation and will reduce the risk of complications.

Don’t smoke if you want a boy!

It is known that men and women who smoke are more likely to take longer to conceive when trying for a baby, but new research suggests that smoking may also influence the sex of the baby!

The number of boys relative to the number of girls born has fallen in many Western countries. A Scandinavian study investigated whether parental smoking might be a factor that could influence this. They assessed the smoking habits around the time of conception in the parents of almost 12000 children. It was found that the more cigarettes that were smoked by the mothers and fathers, the lower the likelihood of them having a boy. The ratio of boys to girls born was just over 1.2 in couples who had never smoked compared to around 0.8 when both parents smoked more than 20 cigarettes a day. The reason for this is not clear. Chronic exposure to toxic substances in the environment has been linked to fertility problems in men, but the link between smoking and the sex of the baby is found with both men and women smokers. This effect may be due to the sperm cells that carry a Y chromosome, which lead to conception of a boy, being more sensitive to the effects of smoking than sperm cells that carry an X chromosome, which lead to conception of a girl.

*Reference: Fukuda et al. Lancet 2002; 359:1407-8.