Specialista in Ginecologia e Ostetricia
 |  |  |  |
|---|
HAVING A SMALL BABY
An unborn baby is small if, at that stage of pregnancy, his estimated weight on the ultrasound scan is in the lowest 10% of babies.
Baby’s weight is affected by many factors such as:
-
Parent’s height and weight: taller, heavier women tend to have heavier babies
-
Parent’s ethnicity: for instance, South Asian women tend to have smaller babies
-
Baby’s gender: boys tend to be heavier.
A baby could be small because of a combination of the factors above. If this is the case, he is likely to be healthy because he is meant to be small.
However, sometimes babies are small because they do not grow as well as expected. This is called being ‘growth-restricted’.
Causes of growth restriction include:
-
The placenta not working as well as it should which could be due to medical problems such as pre-eclampsia (high blood pressure in pregnancy associated with other complications). Other factors that might affect placental function are smoking, using drugs or being very anemic.
-
An infection during pregnancy that affects the baby
-
Baby with a developmental or genetic problem
-
Age over 40
-
Maternal kidney problems
-
Diabetes complications.
-
Having had a small baby in the past also increases your risk.
Some risk factors cannot be changed, but it is possible to quit smoking, do not use recreational drugs, leading a healthy lifestyle and eating healthily
If the baby is small but healthy, he or she is not at increased risk of complications.
If he is growth restricted, there is an increased risk of stillbirth (the baby dying in the womb), serious illness and dying shortly after birth. The earlier in pregnancy and the more severely baby’s growth is affected, the more likely it is that a poor outcome. Babies whose growth is only affected later in pregnancy have a better outcome.
Once a small baby has been identified by a growth scan, extra monitoring is offered to assess his growth and wellbeing. It includes monitoring of umbilical cord blood flow and amniotic fluid measurement.
Later in pregnancy cardiotocograph (CTG) monitoring is offered (a tracing of baby’s heart rate)
The timing of the baby’s delivery depends on how affected his growth is and on the umbilical artery doppler measurements. The scans will help to decide whether it is better for him to be born early or if it is safe to continue the pregnancy until term. If the baby is growing and the Doppler tests are normal, it is usually best to wait until at least 37 weeks.
If there are no other complications, it is possible to have a vaginal birth. The baby will be monitored closely during labor. However, depending on the medical conditions, the possibility of a cesarean section is not to be excluded.
Sources and acknowledgments
Having a small baby. October 2014. RCOG patient leaflet information