Hypertension, also known as high blood pressure, occurs when blood pressure reaches or exceeds 140/90. Hypertension affects 10 percent of pregnancies, according to OBGYN.net. While it can be dangerous for the mother and may necessitate bed rest and prescription medications to control, it can also be dangerous for the unborn baby.
Premature Placental Aging
Hypertension in the mother can cause the placenta to age more quickly than in a normal pregnancy. Placental aging occurs when high blood pressure damages blood vessels in the placenta. Nutrition and oxygen supply to the baby can become compromised when the placenta ages too quickly, according to Baby Zone.
Decreased Placental Blood Flow and Fetal Growth Restriction
According to the Mayo Clinic, high blood pressure decreases the amount of blood that is able to circulate through the placenta. Decreased placental blood flow limits nutrients that are able to travel through the placenta, leading to fetal growth restriction and possibly causing low birth weight.
Fetal Hypotension and Low Amniotic Fluid
Low blood pressure, or hypotension, in an unborn baby can occur when the mother has hypertension. GYNOB.com explains that decreased blood flow from the placenta results in low blood pressure in the baby. Decreased amniotic fluid can occur because the baby's kidneys do not create sufficient urine because blood pressure is too low. Fetal urine output contributes to a large portion of the amniotic fluid; therefore if urine output is low, amniotic fluid levels can also be low.
Increased Risk of Diseases
When hypertension occurs during pregnancy, the unborn baby can be affected for the rest of its life. Dr. Alicia M. Lapidus of OBGYN.net says that the risk of being diagnosed with disorders such as coronary artery disease and diabetes increase in individuals whose mothers had hypertension during pregnancy.
Placenta Abruption
In cases of severe hypertension, it is possible for the placenta to detach from the uterus. This condition can be fatal if not urgently treated because hemorrhage, or excessive bleeding, can occur. Placental abruption also prohibits the baby from receiving adequate oxygen and nutrients for survival.
