There are numerous theories regarding the cause of<unk> , but the cause remains controversial. It is thought that<unk>  is due to a combination of factors which may vary between women and include genetics. Women with family members who had<unk>  are more likely to develop the disease. One factor is an adverse reaction to the hormonal changes of pregnancy, in particular, elevated levels of beta human chorionic gonadotropin (β-hCG). This theory would also explain why<unk>  is most frequently encountered in the first trimester (often around 8–12 weeks of gestation), as β-hCG levels are highest at that time and decline afterward. Another postulated cause of<unk>  is an increase in maternal levels of estrogens (decreasing intestinal motility and gastric emptying leading to nausea/vomiting). More recently, another cause of<unk>  was discovered: "Evidence suggests abnormal levels of the hormone GDF15 are associated with<unk> . The validation of a second risk variant, rs1054221, provides further support for GDF15's role in the etiology of<unk> . Additionally, maternal genes appear to play a more significant role than paternal DNA in contributing to the severity of NVP."
Hyperemesis gravidarum
Hyperthyroidism
Postpartum blues
Urinary tract infection
Placenta praevia
Morning sickness  Morning sickness  1
Eclampsia
Puppy pregnancy syndrome