Outcomes We Study

Preterm birth is birth before 37 weeks of pregnancy. The expected length of a pregnancy is 40 weeks, and births that are 3 weeks early or more are considered preterm. Preterm birth is a primary area of investigation within the consortium. 

Preterm birth is the leading cause of infant mortality in the world and is associated with both short-term and long-term illness and disability. The earlier a child is born, the greater the likelihood of death and illness there is across their lifetimes. Little is known about what causes a person to go into labor early. Known risk factors include hypertension, diabetes, and smoking. Social factors also play a major role in driving risk for preterm birth.

Given how common and devastating preterm birth can be, it is closely associated with many of exposures and adverse pregnancy and infant outcomes studied as part of the consortium including as part of the HOPE COVID-19 study and as part of other ongoing studies including the California Prediction of Poor Outcomes of Pregnancy (CPPOP) study, the PRedicting Maturity, MOrtality and Morbidity in PreTerm Newborns (PROMPT) study, the Cancer and Pregnancy Outcomes study, and the Social Determinants of Heart Defects study. 

Small for gestational age and intrauterine growth restriction refer to a baby that is not growing appropriately, and is consequently smaller than we would expect based on the length of pregnancy. 

Small for gestational age babies usually have a birthweight below the 10th percentile for babies the same gestational age (delivered at the same week of pregnancy). 

A baby may be small because they did not receive necessary nutrients and oxygen needed for proper growth and development during pregnancy. This can cause problems for the baby during pregnancy, delivery, or afterwards. 

Babies born small for gestational age may have any of the following problems after birth: 

·       Decreased oxygen levels

·       Low Apgar scores (an assessment that helps identify babies with difficulty adapting after delivery)

·       Meconium aspiration (inhalation of the first stools passed in utero) which can lead to difficulty breathing

·       Hypoglycemia (low blood sugar)

·       Difficulty maintaining normal body temperature

·       Polycythemia (too many red blood cells) 

* See CHOP: Small for Gestational Age for more information.

Pregnancy factors that contribute to small for gestational age birth and outcomes of babies born small for gestational age are studied as part of several consortium studies including as part of the HOPE COVID-19 study and as part of other ongoing studies including CPPOP, PROMPT, Cancer and Pregnancy Outcomes, and Social Determinants of Heart Defects.

Preeclampsia is a pregnancy complication characterized by high blood pressure and signs of damage to another organ system, most often the liver and kidneys. Left untreated, preeclampsia can lead to serious, even fatal, complications for both mother and baby. 

Complications include:

·       Intrauterine growth restriction (link to SGA/IUGR) 

·       Preterm birth

·       Placental abruption

·       HELLP syndrome (which stands for hemolysis (the destruction of red blood cells), elevated liver enzymes and low platelet count — syndrome)) is a more severe form of preeclampsia, and can rapidly become life-threatening for both mother and baby

• Eclampsia. When preeclampsia isn't controlled, eclampsia — which is essentially preeclampsia plus seizures — can develop. It is very difficult to predict which patients will have preeclampsia that is severe enough to result in eclampsia.
• Other organ damage. Preeclampsia may result in damage to the kidneys, liver, lung, heart, or eyes, and may cause a stroke or other brain injury. The amount of injury to other organs depends on the severity of preeclampsia.
• Cardiovascular disease. Having preeclampsia may increase the risk of future heart and blood vessel (cardiovascular) disease. The risk is even greater for women who have had preeclampsia more than once or have had a preterm delivery. 

* See Mayo Clinic: Preeclampsia for more information.

The placenta is an organ that develops in the uterus during pregnancy. It provides oxygen and nutrients to the growing baby and removes waste products from the baby's blood. The placenta attaches to the wall of the uterus, and the baby's umbilical cord arises from it. 

Problems with the placenta can be dangerous for mother or baby. During pregnancy, possible placental problems include placental abruption, placenta previa and placenta accreta. These conditions can cause potentially heavy vaginal bleeding. 

• Placental abruption. If the placenta peels away from the inner wall of the uterus before delivery — either partially or completely — a condition known as placental abruption develops. This can deprive the baby of oxygen and nutrients and cause a pregnant person to bleed heavily. Placenta abruption could result in an emergency situation requiring early delivery. 
• Placenta previa. This condition occurs when the placenta partially or totally covers the cervix — the outlet for the uterus. Placenta previa is more common early in pregnancy and might resolve as the uterus grows. Placenta previa can cause severe vaginal bleeding during pregnancy or delivery. The management of this condition depends on the amount of bleeding, whether the bleeding stops, how far along the pregnancy is, the position of the placenta, and the mother and baby's health. 
• Placenta accreta. Typically, the placenta detaches from the uterine wall after childbirth. With placenta accreta, part or all of the placenta remains firmly attached to the uterus. This condition occurs when the blood vessels and other parts of the placenta grow too deeply into the uterine wall. This can cause severe blood loss during delivery. In aggressive cases, the placenta invades the muscles of the uterus or grows through the uterine wall. 

* See Mayo Clinic: Placenta for more information.

Infant death is when an infant dies in the first year of life. The leading causes of infant death in the US are birth defects, preterm birth and low birth weight, and maternal pregnancy complications. 

* See CDC: Infant Mortality for more information.

Pregnancy and infant factors that contribute to infant mortality are studied as part of several consortium studies including as part of the HOPE COVID-19 study and as part of other ongoing studies including CPPOP, PROMPT, Cancer and Pregnancy Outcomes, Geographic Patterning of Birth Outcomes, and Social Determinants of Heart Defects.

Preterm babies may have more health problems (morbidities) or need to stay in the hospital longer than babies born on time. Some of the problems a preterm baby develops can cause long-term health impacts. Impacts are sometimes observed with respect to: 

• Brain function and Neurodevelopment  -  Premature birth can lead to long-term intellectual and developmental disabilities for babies. These difficulties can cause a person to have trouble or delays in physical development, learning, communicating with others, getting along with others, and taking care of him/herself;
  • Some long-term cognitive disabilities caused by premature birth include: 
    •  Behavior problems, including attention deficit hyperactivity disorder (also called ADHD) and anxiety;
    • Neurological disorders, like cerebral palsy, that affect the brain, spinal cord and nerves throughout the body;
• Lung function -  Preterm birth can lead to both short- and long-term difficulties with breathing and lung function. This includes an increased liklihood of being diagnosed with bronchopulmonary dysplasia (also called BPD). This is a chronic lung disease that causes the lungs to grow abnormally or to be inflamed. Over time, the lungs usually get better, but a premature baby may have anthma or asthma-like symptoms (e.g. difficulty getting enough air, wheezing) throughout his/her life;
• Intestinal problems - Preterm birth can also cause difficulties with intestinal function. A disease that sometimes affects babies born preterm is called necrotizing enterocolitis (also called NEC). This disease affects a baby’s intestines. Intestines help your body break down (digest) food. While most babies with NEC get better, some may have intestinal problems later in life. For example, scarring may cause the intestine to become blocked. And some babies who’ve had surgery to remove part of the intestine may have trouble later getting nutrients from food;
• Vision problems - Children born prematurely are more likely than children born on time to have vision problems. This may include retinopathy of prematurity (ROP) which can cuase blindess.

* See March of Dimes: Preterm Birth for more information.

Pregnancy and infant factors that lead to complications of prematurity are studied as part of several consortium studies including as part of the HOPE COVID-19 study and as part of other ongoing studies including CPPOP, PROMPT, Cancer and Pregnancy Outcomes, and Geographic Patterning of Birth Outcomes.

Chromosomal and Structural birth defects are health conditions that are present at birth. They result from genetic abnormalities and from abnormalities in fetal development.

Birth defects can cause problems in overall health including in how the body develops or how the body works. Common chromosomal birth defects include trisomy 21 (Down syndrome) which results from three copies of chromosome 21, trisomy 18 (Edward syndrome) which results from three copies of chromosome 18, and trimsomy 13 (Patau sundrome) which results from three copies of chromosome 13. Common structural defects include cleft lip and cleft palate, spina bifida, and heart defects. 

* See March of Dimes: Birth Defects for more information.

Pregnancy factors that contribute to placental abnormalties are studied as part of several consortium studies including as part of the HOPE COVID-19 study and other ongoing studies including CPPOP, Cancer and Pregnancy Outcomes, and Social Determinants of Heart Defects.