Nausea during pregnancy:
(1) is common (affecting 50-80% of pregnancies; 67% in current study)
(2) usually starts during the first trimester (early onset)
(3) prevalence peaks between months 2 and 5 of the pregnancy
Risk factors for nausea during pregnancy:
(1) younger age (risk decreases with increasing age; adjusted odds ratio highest when <= 25 years of age, lowest when > 40)
(2) increased gravidity (including miscarriages and abortions)
(3) multiple gestation (twins, triplets, etc.)
Risk factors for onset of nausea after the first trimester (late onset):
(1) Black race
(2) lower level of education
(3) lower income level
Other factors associated with slightly increased risk (Tables 1 and 2)
(1) stopping smoking
(2) presence of a urinary tract infection
(3) presence of pre-eclampsia
(4) presence of oral or genital herpes
(5) presence of vaginal bleeding
(6) presence of obesity
Other factors associated with slightly decreased risk (Tables 1 and 2)
(1) continued smoking during pregnancy
(2) Blacks and Native Americans had lower risk than other racial groups
(3) presence of diabetes
(4) presence of seizures
