Morning sickness, characterized by nausea and sometimes vomiting, is common in pregnancy. It can occur at any time of day, despite its name, and is a normal part of early pregnancy. The hormone Human Chorionic Gonadotropin (HCG) is often associated with this symptom.
Understanding HCG in Pregnancy
Human Chorionic Gonadotropin (HCG) is a hormone produced by the placenta after a fertilized egg implants. It is detected by pregnancy tests and indicates early pregnancy. HCG supports the corpus luteum, which produces progesterone and estrogen to thicken the uterine lining and maintain the pregnancy. HCG levels rise rapidly, nearly doubling every two to three days, throughout the first eight to ten weeks of gestation. This increase signals the body to halt menstruation and prepare for fetal development.
HCG Levels and Morning Sickness Onset
Morning sickness correlates with rising HCG levels in early pregnancy. Symptoms emerge around weeks five or six, coinciding with HCG’s rapid ascent. Morning sickness peaks between weeks eight and ten, when HCG levels are highest. While no specific HCG level universally triggers morning sickness, high concentrations of this hormone may contribute to nausea. Symptoms often diminish as HCG levels decline after the first trimester, usually around weeks 11 to 15.
Factors Influencing Morning Sickness Severity
While HCG levels are linked to morning sickness, other factors influence its intensity. Individuals carrying multiple fetuses often experience more severe morning sickness due to higher HCG levels. Genetic predisposition can also play a role, as some individuals have increased sensitivity to hormonal changes. Other hormones like estrogen, also rising during pregnancy, have been associated with more severe symptoms. Lifestyle factors, including stress, diet, and metabolic variations, can influence nausea and vomiting.
When to Seek Medical Advice
While morning sickness is common, certain signs warrant medical attention. Individuals should consult a healthcare provider if they are unable to keep food or fluids down for 24 hours, experience weight loss, or show signs of dehydration. Dehydration symptoms include very dark urine, reduced urination, dizziness, or lightheadedness. Persistent nausea and vomiting beyond the first trimester, or worsening symptoms, warrant a medical evaluation. Severe cases, known as hyperemesis gravidarum, require care to prevent complications like electrolyte imbalances and malnutrition.