Nausea and vomiting in pregnancy--a contribution to its epidemiology.

Nausea in pregnancy is very common but it is astonishing that so little data are available concerning the cause and course of this disorder. A questionnaire was mailed to all women who had given birth to at least 3 children, the last delivered in 1980 or 1981 in our department. 244 (75%) responded, mean age 33 years, range 23-45. A total of 948 pregnancies resulted in 855 children, 56 spontaneous and 25 legal abortions, 8 twins and 4 ectopics. 70% of all pregnancies were associated with nausea and 52% of the patients always experienced nausea during their pregnancies, while 17% never and 31% only occasionally felt sick. For 91% of the cases, the onset of nausea was during the first 3 months. There was no difference concerning intensity, 'peak nausea' or onset, whereas duration decreased with subsequent pregnancies. 7 of 8 women with twin pregnancies complained of nausea, contrasting to 50% with spontaneous and 80% with legal abortions. Age, smoking or 'pregnancy complications' did not correlate with nausea. There were, however, correlations (p less than 0.05) between nausea and gallbladder disease, gastritis and allergy. All patients with gallbladder disease had nausea and so had 90% of those with allergy and gastritis. There was also a strong correlation (p less than 0.001) between nausea in pregnancy and 'intolerance' of oral contraceptives, as 98% of these women experienced nausea. The data obtained do not support a correlation between HCG and emesis gravidarum, but rather suggest an association with steroidal hormones and liver function.