High blood pressure, or hypertension, during labor is a medical concern that can affect both the birthing parent and the baby. This condition involves blood pressure readings of 140/90 mmHg or higher, confirmed on at least two occasions, and can either pre-exist the pregnancy or develop during it. Management of blood pressure throughout pregnancy and labor is important for a safe delivery and the health of both the mother and baby. It is a common complication, affecting approximately 1 in 12 to 17 pregnant women in the United States.
Types of High Blood Pressure Affecting Labor
High blood pressure disorders during pregnancy are categorized into several types, each influencing labor and delivery. Chronic hypertension is diagnosed when high blood pressure is present before pregnancy or identified within the first 20 weeks of gestation. This condition persists for more than 12 weeks after delivery.
Gestational hypertension develops after 20 weeks of pregnancy in individuals who previously had normal blood pressure. It is characterized by high blood pressure, without signs of organ damage or excess protein in the urine. While often resolving after delivery, about half of those diagnosed with gestational hypertension may later develop preeclampsia.
Preeclampsia is a more severe condition that arises after 20 weeks of pregnancy, involving new-onset high blood pressure along with signs of organ dysfunction, such as high protein levels in urine. Preeclampsia can also be superimposed on chronic hypertension, meaning individuals with pre-existing high blood pressure develop worsening hypertension accompanied by new signs of organ damage.
Risks for Mother and Baby
High blood pressure during labor poses several risks for both the birthing parent and the baby. For the mother, complications can include eclampsia, which involves life-threatening seizures. Another risk is HELLP syndrome, a severe form of preeclampsia characterized by hemolysis (red blood cell breakdown), elevated liver enzymes, and low platelet count.
Other maternal risks include stroke, placental abruption where the placenta separates from the uterine wall prematurely, and damage to organs such as the kidneys, liver, brain, and lungs. These complications can lead to a need for labor induction or a Cesarean section. High blood pressure can also cause fluid to accumulate in the lungs, leading to shortness of breath.
For the baby, high blood pressure can reduce blood flow to the placenta, limiting the oxygen and nutrients received. This can result in complications such as preterm birth, occurring before 37 weeks of pregnancy, and fetal growth restriction, leading to low birth weight (less than 5 pounds, 8 ounces). Babies born early may experience breathing problems and an increased risk of infection. In severe instances, high blood pressure can lead to fetal distress, requiring admission to the neonatal intensive care unit (NICU), or stillbirth.
Managing Blood Pressure During Labor
Managing high blood pressure during labor involves continuous monitoring and specific medical interventions to ensure the safety of both mother and baby. Healthcare providers will closely track blood pressure, often hourly for those with hypertension, and every 15 to 30 minutes for severe cases.
Antihypertensive medications are administered to lower blood pressure. Commonly used drugs include labetalol, hydralazine, and nifedipine, which can be given intravenously or orally as needed. These medications work to gradually reduce blood pressure.
Magnesium sulfate is another medication used, particularly for individuals with preeclampsia, to prevent seizures. This medication is given intravenously and continued for at least 24 hours after delivery. During magnesium sulfate administration, staff will monitor knee reflexes, as a loss of reflexes can indicate elevated magnesium levels, which requires immediate attention. Fluid management is also adjusted to avoid excessive fluid accumulation, which can worsen blood pressure.
Decisions regarding the timing and method of delivery are also influenced by the severity of the high blood pressure. If preeclampsia is severe or progresses, delivery of the baby and placenta is recommended as the definitive treatment. This may involve inducing labor with medications like oxytocin or performing a Cesarean section.
After Delivery: Continued Care
Monitoring for high blood pressure does not end with delivery, as complications can still arise in the postpartum period. Blood pressure peaks three to six days after birth, even in individuals who had normal blood pressure during pregnancy. Postpartum hypertension can occur up to six weeks after delivery, and preeclampsia can even develop for the first time or worsen during this period.
Healthcare providers will continue to monitor blood pressure closely, recommending checks within 7 to 10 days after delivery for those with a history of hypertensive disorders. If blood pressure remains elevated, medication may be continued or initiated to manage the condition. Oral medications such as nifedipine XL or labetalol are prescribed for outpatient management of mild to moderate postpartum hypertension.
The goal is for blood pressure to normalize within days to weeks after delivery. However, individuals with a history of high blood pressure during pregnancy, especially preeclampsia, may have an increased risk of developing high blood pressure and heart disease later in life. Continued follow-up care with a healthcare provider is important to monitor long-term cardiovascular health and address any persistent issues.