Intrauterine growth restriction (IUGR) refers to a fetus with a birth weight below the 10th percentile or two standard deviations below the average weight for its gestational age. If gestational age reaches 37 weeks and the newborn weighs less than 2.5 kilograms, it is also classified as IUGR. Fetal growth restriction is a concern for many expectant mothers.
Causes of fetal growth restriction include:
1. Maternal factors: 40% of fetal weight variation stems from genetic inheritance from both parents, with maternal genetics having a greater influence. This relates to the mother's pre-pregnancy weight, gestational age at delivery, and parity. For instance, pre-pregnancy weight below 54kg, excessive or insufficient weight gain during pregnancy, and increased risk of fetal growth restriction.Maternal malnutrition, particularly insufficient protein and energy intake, chronic hypoxemia or impaired oxygen transport capacity, pregnancy-associated kidney disease, severe anemia, severe heart disease, preeclampsia, chronic hypertension, and other chronic vascular diseases can all impair uterine and placental blood flow and function, leading to fetal malnutrition. Additionally, immune disorders, endocrine disorders, and infectious diseases can all affect fetal growth and development.
Additionally, adverse maternal habits such as smoking, alcohol abuse, or drug misuse, coupled with poor socioeconomic status, further elevate the risk of fetal growth restriction.
2. Fetal factors: Fetal genetic disorders or chromosomal abnormalities often manifest earlier in intrauterine growth restriction. Common examples include chromosomal number and structural abnormalities such as trisomy 21, 18, or 13, and Turner syndrome.Infection by pathogenic microorganisms such as bacteria or viruses—including rubella virus, cytomegalovirus, herpes simplex virus, Toxoplasma gondii, and Treponema pallidum—can cause fetal growth restriction. Twin pregnancies may also lead to this condition.
3. Placental and umbilical cord factors: Placental infarction, inflammation, or dysfunction, along with an excessively long, thin, knotted, or twisted umbilical cord, can impair fetal nutrient acquisition and contribute to intrauterine growth restriction.
How is fetal growth restriction treated?
1. Rest in a left lateral position. Follow a high-protein diet to enhance nutrition.
2. Intermittent oxygen therapy: 1 hour per session, 2–3 times daily.
3. Pharmacological treatment:
(1) Salbutamol 2.4mg orally, 3 times daily. One course of treatment is 7 days.
(2) Intravenous drip of 500ml low-molecular-weight dextran and 8-16ml Salvia miltiorrhiza injection in 250ml 5% glucose solution, once daily. A 7-day course is recommended. This aims to improve microcirculation and placental function.
(3) Intravenous injection of 100ml compound amino acid solution, once daily. A 7-day course is recommended.
4. Enhanced Monitoring
(1) Observe fetal movements 3 times daily.
(2) Fetal monitoring: Perform NST at least weekly. For NST non-reactive patterns, conduct OCT. Terminate pregnancy as appropriate for positive OCT results.
(3) Ultrasound monitoring: Assess amniotic fluid index or maximum amniotic fluid pocket depth weekly.
(4) Urinary E3 or E/C ratio measurement: Weekly.
5. Obstetric Management
(1) If fetal growth and placental function remain favorable after treatment, pregnancy may continue but must not exceed the estimated due date.
(2) If treatment is ineffective and fetal-placental function tests show abnormalities, administer prednisone or dexamethasone 1–2 days before delivery to promote fetal lung maturation, followed by prompt termination of pregnancy.
(3) Immediate cesarean delivery is indicated in the following situations:
① Non-reactive NST with positive CST.
② Ultrasound-detected oligohydramnios with meconium staining grade II or higher.
③ Mothers with fetal growth restriction complicated by other high-risk factors, severe disease, or obstetric abnormalities.
6. Management of Intrauterine Growth Restriction (IUGR) Newborns
(1) Prepare all emergency measures before delivery.
(2) Immediately after delivery, thoroughly clear amniotic fluid and meconium from the airway via endotracheal intubation to prevent respiratory distress syndrome (RDS).
(3) Maintain body warmth.
(4) Initiate glucose solution or breast milk feeding as early as possible.
Friendly Reminder: Fetal growth restriction is often caused by maternal factors. Expectant mothers should pay special attention during pregnancy, ensuring adequate nutrition throughout all stages, attending regular prenatal checkups, and carefully monitoring their physical condition to deliver a healthy baby. Seek medical attention promptly at the first sign of discomfort.